/* * Driver for Atmel AT91 / AT32 Serial ports * Copyright (C) 2003 Rick Bronson * * Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd. * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * * DMA support added by Chip Coldwell. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define PDC_BUFFER_SIZE 512 /* Revisit: We should calculate this based on the actual port settings */ #define PDC_RX_TIMEOUT (3 * 10) /* 3 bytes */ #if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) #define SUPPORT_SYSRQ #endif #include #include "serial_mctrl_gpio.h" static void atmel_start_rx(struct uart_port *port); static void atmel_stop_rx(struct uart_port *port); #ifdef CONFIG_SERIAL_ATMEL_TTYAT /* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we * should coexist with the 8250 driver, such as if we have an external 16C550 * UART. */ #define SERIAL_ATMEL_MAJOR 204 #define MINOR_START 154 #define ATMEL_DEVICENAME "ttyAT" #else /* Use device name ttyS, major 4, minor 64-68. This is the usual serial port * name, but it is legally reserved for the 8250 driver. */ #define SERIAL_ATMEL_MAJOR TTY_MAJOR #define MINOR_START 64 #define ATMEL_DEVICENAME "ttyS" #endif #define ATMEL_ISR_PASS_LIMIT 256 /* UART registers. CR is write-only, hence no GET macro */ #define UART_PUT_CR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_CR) #define UART_GET_MR(port) __raw_readl((port)->membase + ATMEL_US_MR) #define UART_PUT_MR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_MR) #define UART_PUT_IER(port,v) __raw_writel(v, (port)->membase + ATMEL_US_IER) #define UART_PUT_IDR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_IDR) #define UART_GET_IMR(port) __raw_readl((port)->membase + ATMEL_US_IMR) #define UART_GET_CSR(port) __raw_readl((port)->membase + ATMEL_US_CSR) #define UART_GET_CHAR(port) __raw_readl((port)->membase + ATMEL_US_RHR) #define UART_PUT_CHAR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_THR) #define UART_GET_BRGR(port) __raw_readl((port)->membase + ATMEL_US_BRGR) #define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR) #define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR) #define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_TTGR) #define UART_GET_IP_NAME(port) __raw_readl((port)->membase + ATMEL_US_NAME) #define UART_GET_IP_VERSION(port) __raw_readl((port)->membase + ATMEL_US_VERSION) /* PDC registers */ #define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR) #define UART_GET_PTSR(port) __raw_readl((port)->membase + ATMEL_PDC_PTSR) #define UART_PUT_RPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RPR) #define UART_GET_RPR(port) __raw_readl((port)->membase + ATMEL_PDC_RPR) #define UART_PUT_RCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RCR) #define UART_PUT_RNPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNPR) #define UART_PUT_RNCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNCR) #define UART_PUT_TPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_TPR) #define UART_PUT_TCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_TCR) #define UART_GET_TCR(port) __raw_readl((port)->membase + ATMEL_PDC_TCR) struct atmel_dma_buffer { unsigned char *buf; dma_addr_t dma_addr; unsigned int dma_size; unsigned int ofs; }; struct atmel_uart_char { u16 status; u16 ch; }; #define ATMEL_SERIAL_RINGSIZE 1024 /* * We wrap our port structure around the generic uart_port. */ struct atmel_uart_port { struct uart_port uart; /* uart */ struct clk *clk; /* uart clock */ int may_wakeup; /* cached value of device_may_wakeup for times we need to disable it */ u32 backup_imr; /* IMR saved during suspend */ int break_active; /* break being received */ bool use_dma_rx; /* enable DMA receiver */ bool use_pdc_rx; /* enable PDC receiver */ short pdc_rx_idx; /* current PDC RX buffer */ struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */ bool use_dma_tx; /* enable DMA transmitter */ bool use_pdc_tx; /* enable PDC transmitter */ struct atmel_dma_buffer pdc_tx; /* PDC transmitter */ spinlock_t lock_tx; /* port lock */ spinlock_t lock_rx; /* port lock */ struct dma_chan *chan_tx; struct dma_chan *chan_rx; struct dma_async_tx_descriptor *desc_tx; struct dma_async_tx_descriptor *desc_rx; dma_cookie_t cookie_tx; dma_cookie_t cookie_rx; struct scatterlist sg_tx; struct scatterlist sg_rx; struct tasklet_struct tasklet; unsigned int irq_status; unsigned int irq_status_prev; struct circ_buf rx_ring; struct serial_rs485 rs485; /* rs485 settings */ struct mctrl_gpios *gpios; unsigned int tx_done_mask; bool is_usart; /* usart or uart */ struct timer_list uart_timer; /* uart timer */ int (*prepare_rx)(struct uart_port *port); int (*prepare_tx)(struct uart_port *port); void (*schedule_rx)(struct uart_port *port); void (*schedule_tx)(struct uart_port *port); void (*release_rx)(struct uart_port *port); void (*release_tx)(struct uart_port *port); }; static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART]; static DECLARE_BITMAP(atmel_ports_in_use, ATMEL_MAX_UART); #ifdef SUPPORT_SYSRQ static struct console atmel_console; #endif #if defined(CONFIG_OF) static const struct of_device_id atmel_serial_dt_ids[] = { { .compatible = "atmel,at91rm9200-usart" }, { .compatible = "atmel,at91sam9260-usart" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, atmel_serial_dt_ids); #endif static inline struct atmel_uart_port * to_atmel_uart_port(struct uart_port *uart) { return container_of(uart, struct atmel_uart_port, uart); } #ifdef CONFIG_SERIAL_ATMEL_PDC static bool atmel_use_pdc_rx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); return atmel_port->use_pdc_rx; } static bool atmel_use_pdc_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); return atmel_port->use_pdc_tx; } #else static bool atmel_use_pdc_rx(struct uart_port *port) { return false; } static bool atmel_use_pdc_tx(struct uart_port *port) { return false; } #endif static bool atmel_use_dma_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); return atmel_port->use_dma_tx; } static bool atmel_use_dma_rx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); return atmel_port->use_dma_rx; } static unsigned int atmel_get_lines_status(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int status, ret = 0; status = UART_GET_CSR(port); mctrl_gpio_get(atmel_port->gpios, &ret); if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))) { if (ret & TIOCM_CTS) status &= ~ATMEL_US_CTS; else status |= ATMEL_US_CTS; } if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))) { if (ret & TIOCM_DSR) status &= ~ATMEL_US_DSR; else status |= ATMEL_US_DSR; } if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))) { if (ret & TIOCM_RI) status &= ~ATMEL_US_RI; else status |= ATMEL_US_RI; } if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))) { if (ret & TIOCM_CD) status &= ~ATMEL_US_DCD; else status |= ATMEL_US_DCD; } return status; } /* Enable or disable the rs485 support */ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int mode; unsigned long flags; spin_lock_irqsave(&port->lock, flags); /* Disable interrupts */ UART_PUT_IDR(port, atmel_port->tx_done_mask); mode = UART_GET_MR(port); /* Resetting serial mode to RS232 (0x0) */ mode &= ~ATMEL_US_USMODE; atmel_port->rs485 = *rs485conf; if (rs485conf->flags & SER_RS485_ENABLED) { dev_dbg(port->dev, "Setting UART to RS485\n"); atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; if ((rs485conf->delay_rts_after_send) > 0) UART_PUT_TTGR(port, rs485conf->delay_rts_after_send); mode |= ATMEL_US_USMODE_RS485; } else { dev_dbg(port->dev, "Setting UART to RS232\n"); if (atmel_use_pdc_tx(port)) atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; else atmel_port->tx_done_mask = ATMEL_US_TXRDY; } UART_PUT_MR(port, mode); /* Enable interrupts */ UART_PUT_IER(port, atmel_port->tx_done_mask); spin_unlock_irqrestore(&port->lock, flags); } /* * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty. */ static u_int atmel_tx_empty(struct uart_port *port) { return (UART_GET_CSR(port) & ATMEL_US_TXEMPTY) ? TIOCSER_TEMT : 0; } /* * Set state of the modem control output lines */ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl) { unsigned int control = 0; unsigned int mode; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (mctrl & TIOCM_RTS) control |= ATMEL_US_RTSEN; else control |= ATMEL_US_RTSDIS; if (mctrl & TIOCM_DTR) control |= ATMEL_US_DTREN; else control |= ATMEL_US_DTRDIS; UART_PUT_CR(port, control); mctrl_gpio_set(atmel_port->gpios, mctrl); /* Local loopback mode? */ mode = UART_GET_MR(port) & ~ATMEL_US_CHMODE; if (mctrl & TIOCM_LOOP) mode |= ATMEL_US_CHMODE_LOC_LOOP; else mode |= ATMEL_US_CHMODE_NORMAL; /* Resetting serial mode to RS232 (0x0) */ mode &= ~ATMEL_US_USMODE; if (atmel_port->rs485.flags & SER_RS485_ENABLED) { dev_dbg(port->dev, "Setting UART to RS485\n"); if ((atmel_port->rs485.delay_rts_after_send) > 0) UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_after_send); mode |= ATMEL_US_USMODE_RS485; } else { dev_dbg(port->dev, "Setting UART to RS232\n"); } UART_PUT_MR(port, mode); } /* * Get state of the modem control input lines */ static u_int atmel_get_mctrl(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int ret = 0, status; status = UART_GET_CSR(port); /* * The control signals are active low. */ if (!(status & ATMEL_US_DCD)) ret |= TIOCM_CD; if (!(status & ATMEL_US_CTS)) ret |= TIOCM_CTS; if (!(status & ATMEL_US_DSR)) ret |= TIOCM_DSR; if (!(status & ATMEL_US_RI)) ret |= TIOCM_RI; return mctrl_gpio_get(atmel_port->gpios, &ret); } /* * Stop transmitting. */ static void atmel_stop_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_use_pdc_tx(port)) { /* disable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS); } /* Disable interrupts */ UART_PUT_IDR(port, atmel_port->tx_done_mask); if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_start_rx(port); } /* * Start transmitting. */ static void atmel_start_tx(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_use_pdc_tx(port)) { if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN) /* The transmitter is already running. Yes, we really need this.*/ return; if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_stop_rx(port); /* re-enable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); } /* Enable interrupts */ UART_PUT_IER(port, atmel_port->tx_done_mask); } /* * start receiving - port is in process of being opened. */ static void atmel_start_rx(struct uart_port *port) { UART_PUT_CR(port, ATMEL_US_RSTSTA); /* reset status and receiver */ UART_PUT_CR(port, ATMEL_US_RXEN); if (atmel_use_pdc_rx(port)) { /* enable PDC controller */ UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | port->read_status_mask); UART_PUT_PTCR(port, ATMEL_PDC_RXTEN); } else { UART_PUT_IER(port, ATMEL_US_RXRDY); } } /* * Stop receiving - port is in process of being closed. */ static void atmel_stop_rx(struct uart_port *port) { UART_PUT_CR(port, ATMEL_US_RXDIS); if (atmel_use_pdc_rx(port)) { /* disable PDC receive */ UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS); UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | port->read_status_mask); } else { UART_PUT_IDR(port, ATMEL_US_RXRDY); } } /* * Enable modem status interrupts */ static void atmel_enable_ms(struct uart_port *port) { UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC | ATMEL_US_CTSIC); } /* * Control the transmission of a break signal */ static void atmel_break_ctl(struct uart_port *port, int break_state) { if (break_state != 0) UART_PUT_CR(port, ATMEL_US_STTBRK); /* start break */ else UART_PUT_CR(port, ATMEL_US_STPBRK); /* stop break */ } /* * Stores the incoming character in the ring buffer */ static void atmel_buffer_rx_char(struct uart_port *port, unsigned int status, unsigned int ch) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct circ_buf *ring = &atmel_port->rx_ring; struct atmel_uart_char *c; if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE)) /* Buffer overflow, ignore char */ return; c = &((struct atmel_uart_char *)ring->buf)[ring->head]; c->status = status; c->ch = ch; /* Make sure the character is stored before we update head. */ smp_wmb(); ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1); } /* * Deal with parity, framing and overrun errors. */ static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status) { /* clear error */ UART_PUT_CR(port, ATMEL_US_RSTSTA); if (status & ATMEL_US_RXBRK) { /* ignore side-effect */ status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); port->icount.brk++; } if (status & ATMEL_US_PARE) port->icount.parity++; if (status & ATMEL_US_FRAME) port->icount.frame++; if (status & ATMEL_US_OVRE) port->icount.overrun++; } /* * Characters received (called from interrupt handler) */ static void atmel_rx_chars(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int status, ch; status = UART_GET_CSR(port); while (status & ATMEL_US_RXRDY) { ch = UART_GET_CHAR(port); /* * note that the error handling code is * out of the main execution path */ if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME | ATMEL_US_OVRE | ATMEL_US_RXBRK) || atmel_port->break_active)) { /* clear error */ UART_PUT_CR(port, ATMEL_US_RSTSTA); if (status & ATMEL_US_RXBRK && !atmel_port->break_active) { atmel_port->break_active = 1; UART_PUT_IER(port, ATMEL_US_RXBRK); } else { /* * This is either the end-of-break * condition or we've received at * least one character without RXBRK * being set. In both cases, the next * RXBRK will indicate start-of-break. */ UART_PUT_IDR(port, ATMEL_US_RXBRK); status &= ~ATMEL_US_RXBRK; atmel_port->break_active = 0; } } atmel_buffer_rx_char(port, status, ch); status = UART_GET_CSR(port); } tasklet_schedule(&atmel_port->tasklet); } /* * Transmit characters (called from tasklet with TXRDY interrupt * disabled) */ static void atmel_tx_chars(struct uart_port *port) { struct circ_buf *xmit = &port->state->xmit; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (port->x_char && UART_GET_CSR(port) & atmel_port->tx_done_mask) { UART_PUT_CHAR(port, port->x_char); port->icount.tx++; port->x_char = 0; } if (uart_circ_empty(xmit) || uart_tx_stopped(port)) return; while (UART_GET_CSR(port) & atmel_port->tx_done_mask) { UART_PUT_CHAR(port, xmit->buf[xmit->tail]); xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; if (uart_circ_empty(xmit)) break; } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); if (!uart_circ_empty(xmit)) /* Enable interrupts */ UART_PUT_IER(port, atmel_port->tx_done_mask); } static void atmel_complete_tx_dma(void *arg) { struct atmel_uart_port *atmel_port = arg; struct uart_port *port = &atmel_port->uart; struct circ_buf *xmit = &port->state->xmit; struct dma_chan *chan = atmel_port->chan_tx; unsigned long flags; spin_lock_irqsave(&port->lock, flags); if (chan) dmaengine_terminate_all(chan); xmit->tail += sg_dma_len(&atmel_port->sg_tx); xmit->tail &= UART_XMIT_SIZE - 1; port->icount.tx += sg_dma_len(&atmel_port->sg_tx); spin_lock_irq(&atmel_port->lock_tx); async_tx_ack(atmel_port->desc_tx); atmel_port->cookie_tx = -EINVAL; atmel_port->desc_tx = NULL; spin_unlock_irq(&atmel_port->lock_tx); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); /* Do we really need this? */ if (!uart_circ_empty(xmit)) tasklet_schedule(&atmel_port->tasklet); spin_unlock_irqrestore(&port->lock, flags); } static void atmel_release_tx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct dma_chan *chan = atmel_port->chan_tx; if (chan) { dmaengine_terminate_all(chan); dma_release_channel(chan); dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1, DMA_MEM_TO_DEV); } atmel_port->desc_tx = NULL; atmel_port->chan_tx = NULL; atmel_port->cookie_tx = -EINVAL; } /* * Called from tasklet with TXRDY interrupt is disabled. */ static void atmel_tx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct circ_buf *xmit = &port->state->xmit; struct dma_chan *chan = atmel_port->chan_tx; struct dma_async_tx_descriptor *desc; struct scatterlist *sg = &atmel_port->sg_tx; /* Make sure we have an idle channel */ if (atmel_port->desc_tx != NULL) return; if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) { /* * DMA is idle now. * Port xmit buffer is already mapped, * and it is one page... Just adjust * offsets and lengths. Since it is a circular buffer, * we have to transmit till the end, and then the rest. * Take the port lock to get a * consistent xmit buffer state. */ sg->offset = xmit->tail & (UART_XMIT_SIZE - 1); sg_dma_address(sg) = (sg_dma_address(sg) & ~(UART_XMIT_SIZE - 1)) + sg->offset; sg_dma_len(sg) = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); BUG_ON(!sg_dma_len(sg)); desc = dmaengine_prep_slave_sg(chan, sg, 1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!desc) { dev_err(port->dev, "Failed to send via dma!\n"); return; } dma_sync_sg_for_device(port->dev, sg, 1, DMA_MEM_TO_DEV); atmel_port->desc_tx = desc; desc->callback = atmel_complete_tx_dma; desc->callback_param = atmel_port; atmel_port->cookie_tx = dmaengine_submit(desc); } else { if (atmel_port->rs485.flags & SER_RS485_ENABLED) { /* DMA done, stop TX, start RX for RS485 */ atmel_start_rx(port); } } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); } static int atmel_prepare_tx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); dma_cap_mask_t mask; struct dma_slave_config config; int ret, nent; dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); atmel_port->chan_tx = dma_request_slave_channel(port->dev, "tx"); if (atmel_port->chan_tx == NULL) goto chan_err; dev_info(port->dev, "using %s for tx DMA transfers\n", dma_chan_name(atmel_port->chan_tx)); spin_lock_init(&atmel_port->lock_tx); sg_init_table(&atmel_port->sg_tx, 1); /* UART circular tx buffer is an aligned page. */ BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK); sg_set_page(&atmel_port->sg_tx, virt_to_page(port->state->xmit.buf), UART_XMIT_SIZE, (int)port->state->xmit.buf & ~PAGE_MASK); nent = dma_map_sg(port->dev, &atmel_port->sg_tx, 1, DMA_MEM_TO_DEV); if (!nent) { dev_dbg(port->dev, "need to release resource of dma\n"); goto chan_err; } else { dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__, sg_dma_len(&atmel_port->sg_tx), port->state->xmit.buf, sg_dma_address(&atmel_port->sg_tx)); } /* Configure the slave DMA */ memset(&config, 0, sizeof(config)); config.direction = DMA_MEM_TO_DEV; config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; config.dst_addr = port->mapbase + ATMEL_US_THR; ret = dmaengine_device_control(atmel_port->chan_tx, DMA_SLAVE_CONFIG, (unsigned long)&config); if (ret) { dev_err(port->dev, "DMA tx slave configuration failed\n"); goto chan_err; } return 0; chan_err: dev_err(port->dev, "TX channel not available, switch to pio\n"); atmel_port->use_dma_tx = 0; if (atmel_port->chan_tx) atmel_release_tx_dma(port); return -EINVAL; } static void atmel_flip_buffer_rx_dma(struct uart_port *port, char *buf, size_t count) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct tty_port *tport = &port->state->port; dma_sync_sg_for_cpu(port->dev, &atmel_port->sg_rx, 1, DMA_DEV_TO_MEM); tty_insert_flip_string(tport, buf, count); dma_sync_sg_for_device(port->dev, &atmel_port->sg_rx, 1, DMA_DEV_TO_MEM); /* * Drop the lock here since it might end up calling * uart_start(), which takes the lock. */ spin_unlock(&port->lock); tty_flip_buffer_push(tport); spin_lock(&port->lock); } static void atmel_complete_rx_dma(void *arg) { struct uart_port *port = arg; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); tasklet_schedule(&atmel_port->tasklet); } static void atmel_release_rx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct dma_chan *chan = atmel_port->chan_rx; if (chan) { dmaengine_terminate_all(chan); dma_release_channel(chan); dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1, DMA_DEV_TO_MEM); } atmel_port->desc_rx = NULL; atmel_port->chan_rx = NULL; atmel_port->cookie_rx = -EINVAL; } static void atmel_rx_from_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct circ_buf *ring = &atmel_port->rx_ring; struct dma_chan *chan = atmel_port->chan_rx; struct dma_tx_state state; enum dma_status dmastat; size_t pending, count; /* Reset the UART timeout early so that we don't miss one */ UART_PUT_CR(port, ATMEL_US_STTTO); dmastat = dmaengine_tx_status(chan, atmel_port->cookie_rx, &state); /* Restart a new tasklet if DMA status is error */ if (dmastat == DMA_ERROR) { dev_dbg(port->dev, "Get residue error, restart tasklet\n"); UART_PUT_IER(port, ATMEL_US_TIMEOUT); tasklet_schedule(&atmel_port->tasklet); return; } /* current transfer size should no larger than dma buffer */ pending = sg_dma_len(&atmel_port->sg_rx) - state.residue; BUG_ON(pending > sg_dma_len(&atmel_port->sg_rx)); /* * This will take the chars we have so far, * ring->head will record the transfer size, only new bytes come * will insert into the framework. */ if (pending > ring->head) { count = pending - ring->head; atmel_flip_buffer_rx_dma(port, ring->buf + ring->head, count); ring->head += count; if (ring->head == sg_dma_len(&atmel_port->sg_rx)) ring->head = 0; port->icount.rx += count; } UART_PUT_IER(port, ATMEL_US_TIMEOUT); } static int atmel_prepare_rx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct dma_async_tx_descriptor *desc; dma_cap_mask_t mask; struct dma_slave_config config; struct circ_buf *ring; int ret, nent; ring = &atmel_port->rx_ring; dma_cap_zero(mask); dma_cap_set(DMA_CYCLIC, mask); atmel_port->chan_rx = dma_request_slave_channel(port->dev, "rx"); if (atmel_port->chan_rx == NULL) goto chan_err; dev_info(port->dev, "using %s for rx DMA transfers\n", dma_chan_name(atmel_port->chan_rx)); spin_lock_init(&atmel_port->lock_rx); sg_init_table(&atmel_port->sg_rx, 1); /* UART circular rx buffer is an aligned page. */ BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK); sg_set_page(&atmel_port->sg_rx, virt_to_page(ring->buf), ATMEL_SERIAL_RINGSIZE, (int)ring->buf & ~PAGE_MASK); nent = dma_map_sg(port->dev, &atmel_port->sg_rx, 1, DMA_DEV_TO_MEM); if (!nent) { dev_dbg(port->dev, "need to release resource of dma\n"); goto chan_err; } else { dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__, sg_dma_len(&atmel_port->sg_rx), ring->buf, sg_dma_address(&atmel_port->sg_rx)); } /* Configure the slave DMA */ memset(&config, 0, sizeof(config)); config.direction = DMA_DEV_TO_MEM; config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; config.src_addr = port->mapbase + ATMEL_US_RHR; ret = dmaengine_device_control(atmel_port->chan_rx, DMA_SLAVE_CONFIG, (unsigned long)&config); if (ret) { dev_err(port->dev, "DMA rx slave configuration failed\n"); goto chan_err; } /* * Prepare a cyclic dma transfer, assign 2 descriptors, * each one is half ring buffer size */ desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx, sg_dma_address(&atmel_port->sg_rx), sg_dma_len(&atmel_port->sg_rx), sg_dma_len(&atmel_port->sg_rx)/2, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); desc->callback = atmel_complete_rx_dma; desc->callback_param = port; atmel_port->desc_rx = desc; atmel_port->cookie_rx = dmaengine_submit(desc); return 0; chan_err: dev_err(port->dev, "RX channel not available, switch to pio\n"); atmel_port->use_dma_rx = 0; if (atmel_port->chan_rx) atmel_release_rx_dma(port); return -EINVAL; } static void atmel_uart_timer_callback(unsigned long data) { struct uart_port *port = (void *)data; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); tasklet_schedule(&atmel_port->tasklet); mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port)); } /* * receive interrupt handler. */ static void atmel_handle_receive(struct uart_port *port, unsigned int pending) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_use_pdc_rx(port)) { /* * PDC receive. Just schedule the tasklet and let it * figure out the details. * * TODO: We're not handling error flags correctly at * the moment. */ if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) { UART_PUT_IDR(port, (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)); tasklet_schedule(&atmel_port->tasklet); } if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE | ATMEL_US_FRAME | ATMEL_US_PARE)) atmel_pdc_rxerr(port, pending); } if (atmel_use_dma_rx(port)) { if (pending & ATMEL_US_TIMEOUT) { UART_PUT_IDR(port, ATMEL_US_TIMEOUT); tasklet_schedule(&atmel_port->tasklet); } } /* Interrupt receive */ if (pending & ATMEL_US_RXRDY) atmel_rx_chars(port); else if (pending & ATMEL_US_RXBRK) { /* * End of break detected. If it came along with a * character, atmel_rx_chars will handle it. */ UART_PUT_CR(port, ATMEL_US_RSTSTA); UART_PUT_IDR(port, ATMEL_US_RXBRK); atmel_port->break_active = 0; } } /* * transmit interrupt handler. (Transmit is IRQF_NODELAY safe) */ static void atmel_handle_transmit(struct uart_port *port, unsigned int pending) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (pending & atmel_port->tx_done_mask) { /* Either PDC or interrupt transmission */ UART_PUT_IDR(port, atmel_port->tx_done_mask); tasklet_schedule(&atmel_port->tasklet); } } /* * status flags interrupt handler. */ static void atmel_handle_status(struct uart_port *port, unsigned int pending, unsigned int status) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC | ATMEL_US_CTSIC)) { atmel_port->irq_status = status; tasklet_schedule(&atmel_port->tasklet); } } /* * Interrupt handler */ static irqreturn_t atmel_interrupt(int irq, void *dev_id) { struct uart_port *port = dev_id; unsigned int status, pending, pass_counter = 0; do { status = atmel_get_lines_status(port); pending = status & UART_GET_IMR(port); if (!pending) break; atmel_handle_receive(port, pending); atmel_handle_status(port, pending, status); atmel_handle_transmit(port, pending); } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT); return pass_counter ? IRQ_HANDLED : IRQ_NONE; } static void atmel_release_tx_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; dma_unmap_single(port->dev, pdc->dma_addr, pdc->dma_size, DMA_TO_DEVICE); } /* * Called from tasklet with ENDTX and TXBUFE interrupts disabled. */ static void atmel_tx_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct circ_buf *xmit = &port->state->xmit; struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; int count; /* nothing left to transmit? */ if (UART_GET_TCR(port)) return; xmit->tail += pdc->ofs; xmit->tail &= UART_XMIT_SIZE - 1; port->icount.tx += pdc->ofs; pdc->ofs = 0; /* more to transmit - setup next transfer */ /* disable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS); if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) { dma_sync_single_for_device(port->dev, pdc->dma_addr, pdc->dma_size, DMA_TO_DEVICE); count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); pdc->ofs = count; UART_PUT_TPR(port, pdc->dma_addr + xmit->tail); UART_PUT_TCR(port, count); /* re-enable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); /* Enable interrupts */ UART_PUT_IER(port, atmel_port->tx_done_mask); } else { if ((atmel_port->rs485.flags & SER_RS485_ENABLED) && !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) { /* DMA done, stop TX, start RX for RS485 */ atmel_start_rx(port); } } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); } static int atmel_prepare_tx_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx; struct circ_buf *xmit = &port->state->xmit; pdc->buf = xmit->buf; pdc->dma_addr = dma_map_single(port->dev, pdc->buf, UART_XMIT_SIZE, DMA_TO_DEVICE); pdc->dma_size = UART_XMIT_SIZE; pdc->ofs = 0; return 0; } static void atmel_rx_from_ring(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct circ_buf *ring = &atmel_port->rx_ring; unsigned int flg; unsigned int status; while (ring->head != ring->tail) { struct atmel_uart_char c; /* Make sure c is loaded after head. */ smp_rmb(); c = ((struct atmel_uart_char *)ring->buf)[ring->tail]; ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1); port->icount.rx++; status = c.status; flg = TTY_NORMAL; /* * note that the error handling code is * out of the main execution path */ if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME | ATMEL_US_OVRE | ATMEL_US_RXBRK))) { if (status & ATMEL_US_RXBRK) { /* ignore side-effect */ status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); port->icount.brk++; if (uart_handle_break(port)) continue; } if (status & ATMEL_US_PARE) port->icount.parity++; if (status & ATMEL_US_FRAME) port->icount.frame++; if (status & ATMEL_US_OVRE) port->icount.overrun++; status &= port->read_status_mask; if (status & ATMEL_US_RXBRK) flg = TTY_BREAK; else if (status & ATMEL_US_PARE) flg = TTY_PARITY; else if (status & ATMEL_US_FRAME) flg = TTY_FRAME; } if (uart_handle_sysrq_char(port, c.ch)) continue; uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg); } /* * Drop the lock here since it might end up calling * uart_start(), which takes the lock. */ spin_unlock(&port->lock); tty_flip_buffer_push(&port->state->port); spin_lock(&port->lock); } static void atmel_release_rx_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); int i; for (i = 0; i < 2; i++) { struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i]; dma_unmap_single(port->dev, pdc->dma_addr, pdc->dma_size, DMA_FROM_DEVICE); kfree(pdc->buf); } } static void atmel_rx_from_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct tty_port *tport = &port->state->port; struct atmel_dma_buffer *pdc; int rx_idx = atmel_port->pdc_rx_idx; unsigned int head; unsigned int tail; unsigned int count; do { /* Reset the UART timeout early so that we don't miss one */ UART_PUT_CR(port, ATMEL_US_STTTO); pdc = &atmel_port->pdc_rx[rx_idx]; head = UART_GET_RPR(port) - pdc->dma_addr; tail = pdc->ofs; /* If the PDC has switched buffers, RPR won't contain * any address within the current buffer. Since head * is unsigned, we just need a one-way comparison to * find out. * * In this case, we just need to consume the entire * buffer and resubmit it for DMA. This will clear the * ENDRX bit as well, so that we can safely re-enable * all interrupts below. */ head = min(head, pdc->dma_size); if (likely(head != tail)) { dma_sync_single_for_cpu(port->dev, pdc->dma_addr, pdc->dma_size, DMA_FROM_DEVICE); /* * head will only wrap around when we recycle * the DMA buffer, and when that happens, we * explicitly set tail to 0. So head will * always be greater than tail. */ count = head - tail; tty_insert_flip_string(tport, pdc->buf + pdc->ofs, count); dma_sync_single_for_device(port->dev, pdc->dma_addr, pdc->dma_size, DMA_FROM_DEVICE); port->icount.rx += count; pdc->ofs = head; } /* * If the current buffer is full, we need to check if * the next one contains any additional data. */ if (head >= pdc->dma_size) { pdc->ofs = 0; UART_PUT_RNPR(port, pdc->dma_addr); UART_PUT_RNCR(port, pdc->dma_size); rx_idx = !rx_idx; atmel_port->pdc_rx_idx = rx_idx; } } while (head >= pdc->dma_size); /* * Drop the lock here since it might end up calling * uart_start(), which takes the lock. */ spin_unlock(&port->lock); tty_flip_buffer_push(tport); spin_lock(&port->lock); UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); } static int atmel_prepare_rx_pdc(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); int i; for (i = 0; i < 2; i++) { struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i]; pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL); if (pdc->buf == NULL) { if (i != 0) { dma_unmap_single(port->dev, atmel_port->pdc_rx[0].dma_addr, PDC_BUFFER_SIZE, DMA_FROM_DEVICE); kfree(atmel_port->pdc_rx[0].buf); } atmel_port->use_pdc_rx = 0; return -ENOMEM; } pdc->dma_addr = dma_map_single(port->dev, pdc->buf, PDC_BUFFER_SIZE, DMA_FROM_DEVICE); pdc->dma_size = PDC_BUFFER_SIZE; pdc->ofs = 0; } atmel_port->pdc_rx_idx = 0; UART_PUT_RPR(port, atmel_port->pdc_rx[0].dma_addr); UART_PUT_RCR(port, PDC_BUFFER_SIZE); UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr); UART_PUT_RNCR(port, PDC_BUFFER_SIZE); return 0; } /* * tasklet handling tty stuff outside the interrupt handler. */ static void atmel_tasklet_func(unsigned long data) { struct uart_port *port = (struct uart_port *)data; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int status; unsigned int status_change; /* The interrupt handler does not take the lock */ spin_lock(&port->lock); atmel_port->schedule_tx(port); status = atmel_port->irq_status; status_change = status ^ atmel_port->irq_status_prev; if (status_change & (ATMEL_US_RI | ATMEL_US_DSR | ATMEL_US_DCD | ATMEL_US_CTS)) { /* TODO: All reads to CSR will clear these interrupts! */ if (status_change & ATMEL_US_RI) port->icount.rng++; if (status_change & ATMEL_US_DSR) port->icount.dsr++; if (status_change & ATMEL_US_DCD) uart_handle_dcd_change(port, !(status & ATMEL_US_DCD)); if (status_change & ATMEL_US_CTS) uart_handle_cts_change(port, !(status & ATMEL_US_CTS)); wake_up_interruptible(&port->state->port.delta_msr_wait); atmel_port->irq_status_prev = status; } atmel_port->schedule_rx(port); spin_unlock(&port->lock); } static int atmel_init_property(struct atmel_uart_port *atmel_port, struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev); if (np) { /* DMA/PDC usage specification */ if (of_get_property(np, "atmel,use-dma-rx", NULL)) { if (of_get_property(np, "dmas", NULL)) { atmel_port->use_dma_rx = true; atmel_port->use_pdc_rx = false; } else { atmel_port->use_dma_rx = false; atmel_port->use_pdc_rx = true; } } else { atmel_port->use_dma_rx = false; atmel_port->use_pdc_rx = false; } if (of_get_property(np, "atmel,use-dma-tx", NULL)) { if (of_get_property(np, "dmas", NULL)) { atmel_port->use_dma_tx = true; atmel_port->use_pdc_tx = false; } else { atmel_port->use_dma_tx = false; atmel_port->use_pdc_tx = true; } } else { atmel_port->use_dma_tx = false; atmel_port->use_pdc_tx = false; } } else { atmel_port->use_pdc_rx = pdata->use_dma_rx; atmel_port->use_pdc_tx = pdata->use_dma_tx; atmel_port->use_dma_rx = false; atmel_port->use_dma_tx = false; } return 0; } static void atmel_init_rs485(struct atmel_uart_port *atmel_port, struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev); if (np) { u32 rs485_delay[2]; /* rs485 properties */ if (of_property_read_u32_array(np, "rs485-rts-delay", rs485_delay, 2) == 0) { struct serial_rs485 *rs485conf = &atmel_port->rs485; rs485conf->delay_rts_before_send = rs485_delay[0]; rs485conf->delay_rts_after_send = rs485_delay[1]; rs485conf->flags = 0; if (of_get_property(np, "rs485-rx-during-tx", NULL)) rs485conf->flags |= SER_RS485_RX_DURING_TX; if (of_get_property(np, "linux,rs485-enabled-at-boot-time", NULL)) rs485conf->flags |= SER_RS485_ENABLED; } } else { atmel_port->rs485 = pdata->rs485; } } static void atmel_set_ops(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_use_dma_rx(port)) { atmel_port->prepare_rx = &atmel_prepare_rx_dma; atmel_port->schedule_rx = &atmel_rx_from_dma; atmel_port->release_rx = &atmel_release_rx_dma; } else if (atmel_use_pdc_rx(port)) { atmel_port->prepare_rx = &atmel_prepare_rx_pdc; atmel_port->schedule_rx = &atmel_rx_from_pdc; atmel_port->release_rx = &atmel_release_rx_pdc; } else { atmel_port->prepare_rx = NULL; atmel_port->schedule_rx = &atmel_rx_from_ring; atmel_port->release_rx = NULL; } if (atmel_use_dma_tx(port)) { atmel_port->prepare_tx = &atmel_prepare_tx_dma; atmel_port->schedule_tx = &atmel_tx_dma; atmel_port->release_tx = &atmel_release_tx_dma; } else if (atmel_use_pdc_tx(port)) { atmel_port->prepare_tx = &atmel_prepare_tx_pdc; atmel_port->schedule_tx = &atmel_tx_pdc; atmel_port->release_tx = &atmel_release_tx_pdc; } else { atmel_port->prepare_tx = NULL; atmel_port->schedule_tx = &atmel_tx_chars; atmel_port->release_tx = NULL; } } /* * Get ip name usart or uart */ static void atmel_get_ip_name(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); int name = UART_GET_IP_NAME(port); u32 version; int usart, uart; /* usart and uart ascii */ usart = 0x55534152; uart = 0x44424755; atmel_port->is_usart = false; if (name == usart) { dev_dbg(port->dev, "This is usart\n"); atmel_port->is_usart = true; } else if (name == uart) { dev_dbg(port->dev, "This is uart\n"); atmel_port->is_usart = false; } else { /* fallback for older SoCs: use version field */ version = UART_GET_IP_VERSION(port); switch (version) { case 0x302: case 0x10213: dev_dbg(port->dev, "This version is usart\n"); atmel_port->is_usart = true; break; case 0x203: case 0x10202: dev_dbg(port->dev, "This version is uart\n"); atmel_port->is_usart = false; break; default: dev_err(port->dev, "Not supported ip name nor version, set to uart\n"); } } } /* * Perform initialization and enable port for reception */ static int atmel_startup(struct uart_port *port) { struct platform_device *pdev = to_platform_device(port->dev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); struct tty_struct *tty = port->state->port.tty; int retval; /* * Ensure that no interrupts are enabled otherwise when * request_irq() is called we could get stuck trying to * handle an unexpected interrupt */ UART_PUT_IDR(port, -1); /* * Allocate the IRQ */ retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED, tty ? tty->name : "atmel_serial", port); if (retval) { dev_err(port->dev, "atmel_startup - Can't get irq\n"); return retval; } /* * Initialize DMA (if necessary) */ atmel_init_property(atmel_port, pdev); if (atmel_port->prepare_rx) { retval = atmel_port->prepare_rx(port); if (retval < 0) atmel_set_ops(port); } if (atmel_port->prepare_tx) { retval = atmel_port->prepare_tx(port); if (retval < 0) atmel_set_ops(port); } /* Save current CSR for comparison in atmel_tasklet_func() */ atmel_port->irq_status_prev = atmel_get_lines_status(port); atmel_port->irq_status = atmel_port->irq_status_prev; /* * Finally, enable the serial port */ UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); /* enable xmit & rcvr */ UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN); setup_timer(&atmel_port->uart_timer, atmel_uart_timer_callback, (unsigned long)port); if (atmel_use_pdc_rx(port)) { /* set UART timeout */ if (!atmel_port->is_usart) { mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port)); /* set USART timeout */ } else { UART_PUT_RTOR(port, PDC_RX_TIMEOUT); UART_PUT_CR(port, ATMEL_US_STTTO); UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); } /* enable PDC controller */ UART_PUT_PTCR(port, ATMEL_PDC_RXTEN); } else if (atmel_use_dma_rx(port)) { /* set UART timeout */ if (!atmel_port->is_usart) { mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port)); /* set USART timeout */ } else { UART_PUT_RTOR(port, PDC_RX_TIMEOUT); UART_PUT_CR(port, ATMEL_US_STTTO); UART_PUT_IER(port, ATMEL_US_TIMEOUT); } } else { /* enable receive only */ UART_PUT_IER(port, ATMEL_US_RXRDY); } return 0; } /* * Disable the port */ static void atmel_shutdown(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); /* * Prevent any tasklets being scheduled during * cleanup */ del_timer_sync(&atmel_port->uart_timer); /* * Clear out any scheduled tasklets before * we destroy the buffers */ tasklet_kill(&atmel_port->tasklet); /* * Ensure everything is stopped and * disable all interrupts, port and break condition. */ atmel_stop_rx(port); atmel_stop_tx(port); UART_PUT_CR(port, ATMEL_US_RSTSTA); UART_PUT_IDR(port, -1); /* * Shut-down the DMA. */ if (atmel_port->release_rx) atmel_port->release_rx(port); if (atmel_port->release_tx) atmel_port->release_tx(port); /* * Reset ring buffer pointers */ atmel_port->rx_ring.head = 0; atmel_port->rx_ring.tail = 0; /* * Free the interrupt */ free_irq(port->irq, port); } /* * Flush any TX data submitted for DMA. Called when the TX circular * buffer is reset. */ static void atmel_flush_buffer(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_use_pdc_tx(port)) { UART_PUT_TCR(port, 0); atmel_port->pdc_tx.ofs = 0; } } /* * Power / Clock management. */ static void atmel_serial_pm(struct uart_port *port, unsigned int state, unsigned int oldstate) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); switch (state) { case 0: /* * Enable the peripheral clock for this serial port. * This is called on uart_open() or a resume event. */ clk_prepare_enable(atmel_port->clk); /* re-enable interrupts if we disabled some on suspend */ UART_PUT_IER(port, atmel_port->backup_imr); break; case 3: /* Back up the interrupt mask and disable all interrupts */ atmel_port->backup_imr = UART_GET_IMR(port); UART_PUT_IDR(port, -1); /* * Disable the peripheral clock for this serial port. * This is called on uart_close() or a suspend event. */ clk_disable_unprepare(atmel_port->clk); break; default: dev_err(port->dev, "atmel_serial: unknown pm %d\n", state); } } /* * Change the port parameters */ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { unsigned long flags; unsigned int mode, imr, quot, baud; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); /* Get current mode register */ mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL | ATMEL_US_NBSTOP | ATMEL_US_PAR | ATMEL_US_USMODE); baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); quot = uart_get_divisor(port, baud); if (quot > 65535) { /* BRGR is 16-bit, so switch to slower clock */ quot /= 8; mode |= ATMEL_US_USCLKS_MCK_DIV8; } /* byte size */ switch (termios->c_cflag & CSIZE) { case CS5: mode |= ATMEL_US_CHRL_5; break; case CS6: mode |= ATMEL_US_CHRL_6; break; case CS7: mode |= ATMEL_US_CHRL_7; break; default: mode |= ATMEL_US_CHRL_8; break; } /* stop bits */ if (termios->c_cflag & CSTOPB) mode |= ATMEL_US_NBSTOP_2; /* parity */ if (termios->c_cflag & PARENB) { /* Mark or Space parity */ if (termios->c_cflag & CMSPAR) { if (termios->c_cflag & PARODD) mode |= ATMEL_US_PAR_MARK; else mode |= ATMEL_US_PAR_SPACE; } else if (termios->c_cflag & PARODD) mode |= ATMEL_US_PAR_ODD; else mode |= ATMEL_US_PAR_EVEN; } else mode |= ATMEL_US_PAR_NONE; /* hardware handshake (RTS/CTS) */ if (termios->c_cflag & CRTSCTS) mode |= ATMEL_US_USMODE_HWHS; else mode |= ATMEL_US_USMODE_NORMAL; spin_lock_irqsave(&port->lock, flags); port->read_status_mask = ATMEL_US_OVRE; if (termios->c_iflag & INPCK) port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE); if (termios->c_iflag & (BRKINT | PARMRK)) port->read_status_mask |= ATMEL_US_RXBRK; if (atmel_use_pdc_rx(port)) /* need to enable error interrupts */ UART_PUT_IER(port, port->read_status_mask); /* * Characters to ignore */ port->ignore_status_mask = 0; if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE); if (termios->c_iflag & IGNBRK) { port->ignore_status_mask |= ATMEL_US_RXBRK; /* * If we're ignoring parity and break indicators, * ignore overruns too (for real raw support). */ if (termios->c_iflag & IGNPAR) port->ignore_status_mask |= ATMEL_US_OVRE; } /* TODO: Ignore all characters if CREAD is set.*/ /* update the per-port timeout */ uart_update_timeout(port, termios->c_cflag, baud); /* * save/disable interrupts. The tty layer will ensure that the * transmitter is empty if requested by the caller, so there's * no need to wait for it here. */ imr = UART_GET_IMR(port); UART_PUT_IDR(port, -1); /* disable receiver and transmitter */ UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS); /* Resetting serial mode to RS232 (0x0) */ mode &= ~ATMEL_US_USMODE; if (atmel_port->rs485.flags & SER_RS485_ENABLED) { if ((atmel_port->rs485.delay_rts_after_send) > 0) UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_after_send); mode |= ATMEL_US_USMODE_RS485; } /* set the parity, stop bits and data size */ UART_PUT_MR(port, mode); /* set the baud rate */ UART_PUT_BRGR(port, quot); UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN); /* restore interrupts */ UART_PUT_IER(port, imr); /* CTS flow-control and modem-status interrupts */ if (UART_ENABLE_MS(port, termios->c_cflag)) port->ops->enable_ms(port); spin_unlock_irqrestore(&port->lock, flags); } static void atmel_set_ldisc(struct uart_port *port, int new) { if (new == N_PPS) { port->flags |= UPF_HARDPPS_CD; atmel_enable_ms(port); } else { port->flags &= ~UPF_HARDPPS_CD; } } /* * Return string describing the specified port */ static const char *atmel_type(struct uart_port *port) { return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL; } /* * Release the memory region(s) being used by 'port'. */ static void atmel_release_port(struct uart_port *port) { struct platform_device *pdev = to_platform_device(port->dev); int size = pdev->resource[0].end - pdev->resource[0].start + 1; release_mem_region(port->mapbase, size); if (port->flags & UPF_IOREMAP) { iounmap(port->membase); port->membase = NULL; } } /* * Request the memory region(s) being used by 'port'. */ static int atmel_request_port(struct uart_port *port) { struct platform_device *pdev = to_platform_device(port->dev); int size = pdev->resource[0].end - pdev->resource[0].start + 1; if (!request_mem_region(port->mapbase, size, "atmel_serial")) return -EBUSY; if (port->flags & UPF_IOREMAP) { port->membase = ioremap(port->mapbase, size); if (port->membase == NULL) { release_mem_region(port->mapbase, size); return -ENOMEM; } } return 0; } /* * Configure/autoconfigure the port. */ static void atmel_config_port(struct uart_port *port, int flags) { if (flags & UART_CONFIG_TYPE) { port->type = PORT_ATMEL; atmel_request_port(port); } } /* * Verify the new serial_struct (for TIOCSSERIAL). */ static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser) { int ret = 0; if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL) ret = -EINVAL; if (port->irq != ser->irq) ret = -EINVAL; if (ser->io_type != SERIAL_IO_MEM) ret = -EINVAL; if (port->uartclk / 16 != ser->baud_base) ret = -EINVAL; if ((void *)port->mapbase != ser->iomem_base) ret = -EINVAL; if (port->iobase != ser->port) ret = -EINVAL; if (ser->hub6 != 0) ret = -EINVAL; return ret; } #ifdef CONFIG_CONSOLE_POLL static int atmel_poll_get_char(struct uart_port *port) { while (!(UART_GET_CSR(port) & ATMEL_US_RXRDY)) cpu_relax(); return UART_GET_CHAR(port); } static void atmel_poll_put_char(struct uart_port *port, unsigned char ch) { while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY)) cpu_relax(); UART_PUT_CHAR(port, ch); } #endif static int atmel_ioctl(struct uart_port *port, unsigned int cmd, unsigned long arg) { struct serial_rs485 rs485conf; switch (cmd) { case TIOCSRS485: if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg, sizeof(rs485conf))) return -EFAULT; atmel_config_rs485(port, &rs485conf); break; case TIOCGRS485: if (copy_to_user((struct serial_rs485 *) arg, &(to_atmel_uart_port(port)->rs485), sizeof(rs485conf))) return -EFAULT; break; default: return -ENOIOCTLCMD; } return 0; } static struct uart_ops atmel_pops = { .tx_empty = atmel_tx_empty, .set_mctrl = atmel_set_mctrl, .get_mctrl = atmel_get_mctrl, .stop_tx = atmel_stop_tx, .start_tx = atmel_start_tx, .stop_rx = atmel_stop_rx, .enable_ms = atmel_enable_ms, .break_ctl = atmel_break_ctl, .startup = atmel_startup, .shutdown = atmel_shutdown, .flush_buffer = atmel_flush_buffer, .set_termios = atmel_set_termios, .set_ldisc = atmel_set_ldisc, .type = atmel_type, .release_port = atmel_release_port, .request_port = atmel_request_port, .config_port = atmel_config_port, .verify_port = atmel_verify_port, .pm = atmel_serial_pm, .ioctl = atmel_ioctl, #ifdef CONFIG_CONSOLE_POLL .poll_get_char = atmel_poll_get_char, .poll_put_char = atmel_poll_put_char, #endif }; /* * Configure the port from the platform device resource info. */ static int atmel_init_port(struct atmel_uart_port *atmel_port, struct platform_device *pdev) { int ret; struct uart_port *port = &atmel_port->uart; struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev); if (!atmel_init_property(atmel_port, pdev)) atmel_set_ops(port); atmel_init_rs485(atmel_port, pdev); port->iotype = UPIO_MEM; port->flags = UPF_BOOT_AUTOCONF; port->ops = &atmel_pops; port->fifosize = 1; port->dev = &pdev->dev; port->mapbase = pdev->resource[0].start; port->irq = pdev->resource[1].start; tasklet_init(&atmel_port->tasklet, atmel_tasklet_func, (unsigned long)port); memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring)); if (pdata && pdata->regs) { /* Already mapped by setup code */ port->membase = pdata->regs; } else { port->flags |= UPF_IOREMAP; port->membase = NULL; } /* for console, the clock could already be configured */ if (!atmel_port->clk) { atmel_port->clk = clk_get(&pdev->dev, "usart"); if (IS_ERR(atmel_port->clk)) { ret = PTR_ERR(atmel_port->clk); atmel_port->clk = NULL; return ret; } ret = clk_prepare_enable(atmel_port->clk); if (ret) { clk_put(atmel_port->clk); atmel_port->clk = NULL; return ret; } port->uartclk = clk_get_rate(atmel_port->clk); clk_disable_unprepare(atmel_port->clk); /* only enable clock when USART is in use */ } /* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */ if (atmel_port->rs485.flags & SER_RS485_ENABLED) atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; else if (atmel_use_pdc_tx(port)) { port->fifosize = PDC_BUFFER_SIZE; atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; } else { atmel_port->tx_done_mask = ATMEL_US_TXRDY; } return 0; } struct platform_device *atmel_default_console_device; /* the serial console device */ #ifdef CONFIG_SERIAL_ATMEL_CONSOLE static void atmel_console_putchar(struct uart_port *port, int ch) { while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY)) cpu_relax(); UART_PUT_CHAR(port, ch); } /* * Interrupts are disabled on entering */ static void atmel_console_write(struct console *co, const char *s, u_int count) { struct uart_port *port = &atmel_ports[co->index].uart; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); unsigned int status, imr; unsigned int pdc_tx; /* * First, save IMR and then disable interrupts */ imr = UART_GET_IMR(port); UART_PUT_IDR(port, ATMEL_US_RXRDY | atmel_port->tx_done_mask); /* Store PDC transmit status and disable it */ pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN; UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS); uart_console_write(port, s, count, atmel_console_putchar); /* * Finally, wait for transmitter to become empty * and restore IMR */ do { status = UART_GET_CSR(port); } while (!(status & ATMEL_US_TXRDY)); /* Restore PDC transmit status */ if (pdc_tx) UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); /* set interrupts back the way they were */ UART_PUT_IER(port, imr); } /* * If the port was already initialised (eg, by a boot loader), * try to determine the current setup. */ static void __init atmel_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits) { unsigned int mr, quot; /* * If the baud rate generator isn't running, the port wasn't * initialized by the boot loader. */ quot = UART_GET_BRGR(port) & ATMEL_US_CD; if (!quot) return; mr = UART_GET_MR(port) & ATMEL_US_CHRL; if (mr == ATMEL_US_CHRL_8) *bits = 8; else *bits = 7; mr = UART_GET_MR(port) & ATMEL_US_PAR; if (mr == ATMEL_US_PAR_EVEN) *parity = 'e'; else if (mr == ATMEL_US_PAR_ODD) *parity = 'o'; /* * The serial core only rounds down when matching this to a * supported baud rate. Make sure we don't end up slightly * lower than one of those, as it would make us fall through * to a much lower baud rate than we really want. */ *baud = port->uartclk / (16 * (quot - 1)); } static int __init atmel_console_setup(struct console *co, char *options) { int ret; struct uart_port *port = &atmel_ports[co->index].uart; int baud = 115200; int bits = 8; int parity = 'n'; int flow = 'n'; if (port->membase == NULL) { /* Port not initialized yet - delay setup */ return -ENODEV; } ret = clk_prepare_enable(atmel_ports[co->index].clk); if (ret) return ret; UART_PUT_IDR(port, -1); UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN); if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else atmel_console_get_options(port, &baud, &parity, &bits); return uart_set_options(port, co, baud, parity, bits, flow); } static struct uart_driver atmel_uart; static struct console atmel_console = { .name = ATMEL_DEVICENAME, .write = atmel_console_write, .device = uart_console_device, .setup = atmel_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &atmel_uart, }; #define ATMEL_CONSOLE_DEVICE (&atmel_console) /* * Early console initialization (before VM subsystem initialized). */ static int __init atmel_console_init(void) { int ret; if (atmel_default_console_device) { struct atmel_uart_data *pdata = dev_get_platdata(&atmel_default_console_device->dev); int id = pdata->num; struct atmel_uart_port *port = &atmel_ports[id]; port->backup_imr = 0; port->uart.line = id; add_preferred_console(ATMEL_DEVICENAME, id, NULL); ret = atmel_init_port(port, atmel_default_console_device); if (ret) return ret; register_console(&atmel_console); } return 0; } console_initcall(atmel_console_init); /* * Late console initialization. */ static int __init atmel_late_console_init(void) { if (atmel_default_console_device && !(atmel_console.flags & CON_ENABLED)) register_console(&atmel_console); return 0; } core_initcall(atmel_late_console_init); static inline bool atmel_is_console_port(struct uart_port *port) { return port->cons && port->cons->index == port->line; } #else #define ATMEL_CONSOLE_DEVICE NULL static inline bool atmel_is_console_port(struct uart_port *port) { return false; } #endif static struct uart_driver atmel_uart = { .owner = THIS_MODULE, .driver_name = "atmel_serial", .dev_name = ATMEL_DEVICENAME, .major = SERIAL_ATMEL_MAJOR, .minor = MINOR_START, .nr = ATMEL_MAX_UART, .cons = ATMEL_CONSOLE_DEVICE, }; #ifdef CONFIG_PM static bool atmel_serial_clk_will_stop(void) { #ifdef CONFIG_ARCH_AT91 return at91_suspend_entering_slow_clock(); #else return false; #endif } static int atmel_serial_suspend(struct platform_device *pdev, pm_message_t state) { struct uart_port *port = platform_get_drvdata(pdev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); if (atmel_is_console_port(port) && console_suspend_enabled) { /* Drain the TX shifter */ while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY)) cpu_relax(); } /* we can not wake up if we're running on slow clock */ atmel_port->may_wakeup = device_may_wakeup(&pdev->dev); if (atmel_serial_clk_will_stop()) device_set_wakeup_enable(&pdev->dev, 0); uart_suspend_port(&atmel_uart, port); return 0; } static int atmel_serial_resume(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); uart_resume_port(&atmel_uart, port); device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup); return 0; } #else #define atmel_serial_suspend NULL #define atmel_serial_resume NULL #endif static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev) { p->gpios = mctrl_gpio_init(dev, 0); if (IS_ERR_OR_NULL(p->gpios)) return -1; return 0; } static int atmel_serial_probe(struct platform_device *pdev) { struct atmel_uart_port *port; struct device_node *np = pdev->dev.of_node; struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev); void *data; int ret = -ENODEV; BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1)); if (np) ret = of_alias_get_id(np, "serial"); else if (pdata) ret = pdata->num; if (ret < 0) /* port id not found in platform data nor device-tree aliases: * auto-enumerate it */ ret = find_first_zero_bit(atmel_ports_in_use, ATMEL_MAX_UART); if (ret >= ATMEL_MAX_UART) { ret = -ENODEV; goto err; } if (test_and_set_bit(ret, atmel_ports_in_use)) { /* port already in use */ ret = -EBUSY; goto err; } port = &atmel_ports[ret]; port->backup_imr = 0; port->uart.line = ret; ret = atmel_init_gpios(port, &pdev->dev); if (ret < 0) dev_err(&pdev->dev, "%s", "Failed to initialize GPIOs. The serial port may not work as expected"); ret = atmel_init_port(port, pdev); if (ret) goto err; if (!atmel_use_pdc_rx(&port->uart)) { ret = -ENOMEM; data = kmalloc(sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE, GFP_KERNEL); if (!data) goto err_alloc_ring; port->rx_ring.buf = data; } ret = uart_add_one_port(&atmel_uart, &port->uart); if (ret) goto err_add_port; #ifdef CONFIG_SERIAL_ATMEL_CONSOLE if (atmel_is_console_port(&port->uart) && ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) { /* * The serial core enabled the clock for us, so undo * the clk_prepare_enable() in atmel_console_setup() */ clk_disable_unprepare(port->clk); } #endif device_init_wakeup(&pdev->dev, 1); platform_set_drvdata(pdev, port); if (port->rs485.flags & SER_RS485_ENABLED) { UART_PUT_MR(&port->uart, ATMEL_US_USMODE_NORMAL); UART_PUT_CR(&port->uart, ATMEL_US_RTSEN); } /* * Get port name of usart or uart */ atmel_get_ip_name(&port->uart); return 0; err_add_port: kfree(port->rx_ring.buf); port->rx_ring.buf = NULL; err_alloc_ring: if (!atmel_is_console_port(&port->uart)) { clk_put(port->clk); port->clk = NULL; } err: return ret; } static int atmel_serial_remove(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); int ret = 0; tasklet_kill(&atmel_port->tasklet); device_init_wakeup(&pdev->dev, 0); ret = uart_remove_one_port(&atmel_uart, port); kfree(atmel_port->rx_ring.buf); /* "port" is allocated statically, so we shouldn't free it */ clear_bit(port->line, atmel_ports_in_use); clk_put(atmel_port->clk); return ret; } static struct platform_driver atmel_serial_driver = { .probe = atmel_serial_probe, .remove = atmel_serial_remove, .suspend = atmel_serial_suspend, .resume = atmel_serial_resume, .driver = { .name = "atmel_usart", .owner = THIS_MODULE, .of_match_table = of_match_ptr(atmel_serial_dt_ids), }, }; static int __init atmel_serial_init(void) { int ret; ret = uart_register_driver(&atmel_uart); if (ret) return ret; ret = platform_driver_register(&atmel_serial_driver); if (ret) uart_unregister_driver(&atmel_uart); return ret; } static void __exit atmel_serial_exit(void) { platform_driver_unregister(&atmel_serial_driver); uart_unregister_driver(&atmel_uart); } module_init(atmel_serial_init); module_exit(atmel_serial_exit); MODULE_AUTHOR("Rick Bronson"); MODULE_DESCRIPTION("Atmel AT91 / AT32 serial port driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:atmel_usart");