diff options
Diffstat (limited to 'drivers/spi/spi-atmel.c')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 1093 |
1 files changed, 1093 insertions, 0 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c new file mode 100644 index 00000000000..82dee9a6c0d --- /dev/null +++ b/drivers/spi/spi-atmel.c @@ -0,0 +1,1093 @@ +/* + * Driver for Atmel AT32 and AT91 SPI Controllers + * + * Copyright (C) 2006 Atmel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/clk.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/spi/spi.h> +#include <linux/slab.h> + +#include <asm/io.h> +#include <mach/board.h> +#include <mach/gpio.h> +#include <mach/cpu.h> + +/* SPI register offsets */ +#define SPI_CR 0x0000 +#define SPI_MR 0x0004 +#define SPI_RDR 0x0008 +#define SPI_TDR 0x000c +#define SPI_SR 0x0010 +#define SPI_IER 0x0014 +#define SPI_IDR 0x0018 +#define SPI_IMR 0x001c +#define SPI_CSR0 0x0030 +#define SPI_CSR1 0x0034 +#define SPI_CSR2 0x0038 +#define SPI_CSR3 0x003c +#define SPI_RPR 0x0100 +#define SPI_RCR 0x0104 +#define SPI_TPR 0x0108 +#define SPI_TCR 0x010c +#define SPI_RNPR 0x0110 +#define SPI_RNCR 0x0114 +#define SPI_TNPR 0x0118 +#define SPI_TNCR 0x011c +#define SPI_PTCR 0x0120 +#define SPI_PTSR 0x0124 + +/* Bitfields in CR */ +#define SPI_SPIEN_OFFSET 0 +#define SPI_SPIEN_SIZE 1 +#define SPI_SPIDIS_OFFSET 1 +#define SPI_SPIDIS_SIZE 1 +#define SPI_SWRST_OFFSET 7 +#define SPI_SWRST_SIZE 1 +#define SPI_LASTXFER_OFFSET 24 +#define SPI_LASTXFER_SIZE 1 + +/* Bitfields in MR */ +#define SPI_MSTR_OFFSET 0 +#define SPI_MSTR_SIZE 1 +#define SPI_PS_OFFSET 1 +#define SPI_PS_SIZE 1 +#define SPI_PCSDEC_OFFSET 2 +#define SPI_PCSDEC_SIZE 1 +#define SPI_FDIV_OFFSET 3 +#define SPI_FDIV_SIZE 1 +#define SPI_MODFDIS_OFFSET 4 +#define SPI_MODFDIS_SIZE 1 +#define SPI_LLB_OFFSET 7 +#define SPI_LLB_SIZE 1 +#define SPI_PCS_OFFSET 16 +#define SPI_PCS_SIZE 4 +#define SPI_DLYBCS_OFFSET 24 +#define SPI_DLYBCS_SIZE 8 + +/* Bitfields in RDR */ +#define SPI_RD_OFFSET 0 +#define SPI_RD_SIZE 16 + +/* Bitfields in TDR */ +#define SPI_TD_OFFSET 0 +#define SPI_TD_SIZE 16 + +/* Bitfields in SR */ +#define SPI_RDRF_OFFSET 0 +#define SPI_RDRF_SIZE 1 +#define SPI_TDRE_OFFSET 1 +#define SPI_TDRE_SIZE 1 +#define SPI_MODF_OFFSET 2 +#define SPI_MODF_SIZE 1 +#define SPI_OVRES_OFFSET 3 +#define SPI_OVRES_SIZE 1 +#define SPI_ENDRX_OFFSET 4 +#define SPI_ENDRX_SIZE 1 +#define SPI_ENDTX_OFFSET 5 +#define SPI_ENDTX_SIZE 1 +#define SPI_RXBUFF_OFFSET 6 +#define SPI_RXBUFF_SIZE 1 +#define SPI_TXBUFE_OFFSET 7 +#define SPI_TXBUFE_SIZE 1 +#define SPI_NSSR_OFFSET 8 +#define SPI_NSSR_SIZE 1 +#define SPI_TXEMPTY_OFFSET 9 +#define SPI_TXEMPTY_SIZE 1 +#define SPI_SPIENS_OFFSET 16 +#define SPI_SPIENS_SIZE 1 + +/* Bitfields in CSR0 */ +#define SPI_CPOL_OFFSET 0 +#define SPI_CPOL_SIZE 1 +#define SPI_NCPHA_OFFSET 1 +#define SPI_NCPHA_SIZE 1 +#define SPI_CSAAT_OFFSET 3 +#define SPI_CSAAT_SIZE 1 +#define SPI_BITS_OFFSET 4 +#define SPI_BITS_SIZE 4 +#define SPI_SCBR_OFFSET 8 +#define SPI_SCBR_SIZE 8 +#define SPI_DLYBS_OFFSET 16 +#define SPI_DLYBS_SIZE 8 +#define SPI_DLYBCT_OFFSET 24 +#define SPI_DLYBCT_SIZE 8 + +/* Bitfields in RCR */ +#define SPI_RXCTR_OFFSET 0 +#define SPI_RXCTR_SIZE 16 + +/* Bitfields in TCR */ +#define SPI_TXCTR_OFFSET 0 +#define SPI_TXCTR_SIZE 16 + +/* Bitfields in RNCR */ +#define SPI_RXNCR_OFFSET 0 +#define SPI_RXNCR_SIZE 16 + +/* Bitfields in TNCR */ +#define SPI_TXNCR_OFFSET 0 +#define SPI_TXNCR_SIZE 16 + +/* Bitfields in PTCR */ +#define SPI_RXTEN_OFFSET 0 +#define SPI_RXTEN_SIZE 1 +#define SPI_RXTDIS_OFFSET 1 +#define SPI_RXTDIS_SIZE 1 +#define SPI_TXTEN_OFFSET 8 +#define SPI_TXTEN_SIZE 1 +#define SPI_TXTDIS_OFFSET 9 +#define SPI_TXTDIS_SIZE 1 + +/* Constants for BITS */ +#define SPI_BITS_8_BPT 0 +#define SPI_BITS_9_BPT 1 +#define SPI_BITS_10_BPT 2 +#define SPI_BITS_11_BPT 3 +#define SPI_BITS_12_BPT 4 +#define SPI_BITS_13_BPT 5 +#define SPI_BITS_14_BPT 6 +#define SPI_BITS_15_BPT 7 +#define SPI_BITS_16_BPT 8 + +/* Bit manipulation macros */ +#define SPI_BIT(name) \ + (1 << SPI_##name##_OFFSET) +#define SPI_BF(name,value) \ + (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET) +#define SPI_BFEXT(name,value) \ + (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1)) +#define SPI_BFINS(name,value,old) \ + ( ((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \ + | SPI_BF(name,value)) + +/* Register access macros */ +#define spi_readl(port,reg) \ + __raw_readl((port)->regs + SPI_##reg) +#define spi_writel(port,reg,value) \ + __raw_writel((value), (port)->regs + SPI_##reg) + + +/* + * The core SPI transfer engine just talks to a register bank to set up + * DMA transfers; transfer queue progress is driven by IRQs. The clock + * framework provides the base clock, subdivided for each spi_device. + */ +struct atmel_spi { + spinlock_t lock; + + void __iomem *regs; + int irq; + struct clk *clk; + struct platform_device *pdev; + struct spi_device *stay; + + u8 stopping; + struct list_head queue; + struct spi_transfer *current_transfer; + unsigned long current_remaining_bytes; + struct spi_transfer *next_transfer; + unsigned long next_remaining_bytes; + + void *buffer; + dma_addr_t buffer_dma; +}; + +/* Controller-specific per-slave state */ +struct atmel_spi_device { + unsigned int npcs_pin; + u32 csr; +}; + +#define BUFFER_SIZE PAGE_SIZE +#define INVALID_DMA_ADDRESS 0xffffffff + +/* + * Version 2 of the SPI controller has + * - CR.LASTXFER + * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero) + * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs) + * - SPI_CSRx.CSAAT + * - SPI_CSRx.SBCR allows faster clocking + * + * We can determine the controller version by reading the VERSION + * register, but I haven't checked that it exists on all chips, and + * this is cheaper anyway. + */ +static bool atmel_spi_is_v2(void) +{ + return !cpu_is_at91rm9200(); +} + +/* + * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby + * they assume that spi slave device state will not change on deselect, so + * that automagic deselection is OK. ("NPCSx rises if no data is to be + * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer + * controllers have CSAAT and friends. + * + * Since the CSAAT functionality is a bit weird on newer controllers as + * well, we use GPIO to control nCSx pins on all controllers, updating + * MR.PCS to avoid confusing the controller. Using GPIOs also lets us + * support active-high chipselects despite the controller's belief that + * only active-low devices/systems exists. + * + * However, at91rm9200 has a second erratum whereby nCS0 doesn't work + * right when driven with GPIO. ("Mode Fault does not allow more than one + * Master on Chip Select 0.") No workaround exists for that ... so for + * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH, + * and (c) will trigger that first erratum in some cases. + * + * TODO: Test if the atmel_spi_is_v2() branch below works on + * AT91RM9200 if we use some other register than CSR0. However, don't + * do this unconditionally since AP7000 has an errata where the BITS + * field in CSR0 overrides all other CSRs. + */ + +static void cs_activate(struct atmel_spi *as, struct spi_device *spi) +{ + struct atmel_spi_device *asd = spi->controller_state; + unsigned active = spi->mode & SPI_CS_HIGH; + u32 mr; + + if (atmel_spi_is_v2()) { + /* + * Always use CSR0. This ensures that the clock + * switches to the correct idle polarity before we + * toggle the CS. + */ + spi_writel(as, CSR0, asd->csr); + spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS) + | SPI_BIT(MSTR)); + mr = spi_readl(as, MR); + gpio_set_value(asd->npcs_pin, active); + } else { + u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0; + int i; + u32 csr; + + /* Make sure clock polarity is correct */ + for (i = 0; i < spi->master->num_chipselect; i++) { + csr = spi_readl(as, CSR0 + 4 * i); + if ((csr ^ cpol) & SPI_BIT(CPOL)) + spi_writel(as, CSR0 + 4 * i, + csr ^ SPI_BIT(CPOL)); + } + + mr = spi_readl(as, MR); + mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); + if (spi->chip_select != 0) + gpio_set_value(asd->npcs_pin, active); + spi_writel(as, MR, mr); + } + + dev_dbg(&spi->dev, "activate %u%s, mr %08x\n", + asd->npcs_pin, active ? " (high)" : "", + mr); +} + +static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) +{ + struct atmel_spi_device *asd = spi->controller_state; + unsigned active = spi->mode & SPI_CS_HIGH; + u32 mr; + + /* only deactivate *this* device; sometimes transfers to + * another device may be active when this routine is called. + */ + mr = spi_readl(as, MR); + if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) { + mr = SPI_BFINS(PCS, 0xf, mr); + spi_writel(as, MR, mr); + } + + dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n", + asd->npcs_pin, active ? " (low)" : "", + mr); + + if (atmel_spi_is_v2() || spi->chip_select != 0) + gpio_set_value(asd->npcs_pin, !active); +} + +static inline int atmel_spi_xfer_is_last(struct spi_message *msg, + struct spi_transfer *xfer) +{ + return msg->transfers.prev == &xfer->transfer_list; +} + +static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer) +{ + return xfer->delay_usecs == 0 && !xfer->cs_change; +} + +static void atmel_spi_next_xfer_data(struct spi_master *master, + struct spi_transfer *xfer, + dma_addr_t *tx_dma, + dma_addr_t *rx_dma, + u32 *plen) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + u32 len = *plen; + + /* use scratch buffer only when rx or tx data is unspecified */ + if (xfer->rx_buf) + *rx_dma = xfer->rx_dma + xfer->len - *plen; + else { + *rx_dma = as->buffer_dma; + if (len > BUFFER_SIZE) + len = BUFFER_SIZE; + } + if (xfer->tx_buf) + *tx_dma = xfer->tx_dma + xfer->len - *plen; + else { + *tx_dma = as->buffer_dma; + if (len > BUFFER_SIZE) + len = BUFFER_SIZE; + memset(as->buffer, 0, len); + dma_sync_single_for_device(&as->pdev->dev, + as->buffer_dma, len, DMA_TO_DEVICE); + } + + *plen = len; +} + +/* + * Submit next transfer for DMA. + * lock is held, spi irq is blocked + */ +static void atmel_spi_next_xfer(struct spi_master *master, + struct spi_message *msg) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + struct spi_transfer *xfer; + u32 len, remaining; + u32 ieval; + dma_addr_t tx_dma, rx_dma; + + if (!as->current_transfer) + xfer = list_entry(msg->transfers.next, + struct spi_transfer, transfer_list); + else if (!as->next_transfer) + xfer = list_entry(as->current_transfer->transfer_list.next, + struct spi_transfer, transfer_list); + else + xfer = NULL; + + if (xfer) { + spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); + + len = xfer->len; + atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len); + remaining = xfer->len - len; + + spi_writel(as, RPR, rx_dma); + spi_writel(as, TPR, tx_dma); + + if (msg->spi->bits_per_word > 8) + len >>= 1; + spi_writel(as, RCR, len); + spi_writel(as, TCR, len); + + dev_dbg(&msg->spi->dev, + " start xfer %p: len %u tx %p/%08x rx %p/%08x\n", + xfer, xfer->len, xfer->tx_buf, xfer->tx_dma, + xfer->rx_buf, xfer->rx_dma); + } else { + xfer = as->next_transfer; + remaining = as->next_remaining_bytes; + } + + as->current_transfer = xfer; + as->current_remaining_bytes = remaining; + + if (remaining > 0) + len = remaining; + else if (!atmel_spi_xfer_is_last(msg, xfer) + && atmel_spi_xfer_can_be_chained(xfer)) { + xfer = list_entry(xfer->transfer_list.next, + struct spi_transfer, transfer_list); + len = xfer->len; + } else + xfer = NULL; + + as->next_transfer = xfer; + + if (xfer) { + u32 total; + + total = len; + atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len); + as->next_remaining_bytes = total - len; + + spi_writel(as, RNPR, rx_dma); + spi_writel(as, TNPR, tx_dma); + + if (msg->spi->bits_per_word > 8) + len >>= 1; + spi_writel(as, RNCR, len); + spi_writel(as, TNCR, len); + + dev_dbg(&msg->spi->dev, + " next xfer %p: len %u tx %p/%08x rx %p/%08x\n", + xfer, xfer->len, xfer->tx_buf, xfer->tx_dma, + xfer->rx_buf, xfer->rx_dma); + ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES); + } else { + spi_writel(as, RNCR, 0); + spi_writel(as, TNCR, 0); + ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES); + } + + /* REVISIT: We're waiting for ENDRX before we start the next + * transfer because we need to handle some difficult timing + * issues otherwise. If we wait for ENDTX in one transfer and + * then starts waiting for ENDRX in the next, it's difficult + * to tell the difference between the ENDRX interrupt we're + * actually waiting for and the ENDRX interrupt of the + * previous transfer. + * + * It should be doable, though. Just not now... + */ + spi_writel(as, IER, ieval); + spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN)); +} + +static void atmel_spi_next_message(struct spi_master *master) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + struct spi_message *msg; + struct spi_device *spi; + + BUG_ON(as->current_transfer); + + msg = list_entry(as->queue.next, struct spi_message, queue); + spi = msg->spi; + + dev_dbg(master->dev.parent, "start message %p for %s\n", + msg, dev_name(&spi->dev)); + + /* select chip if it's not still active */ + if (as->stay) { + if (as->stay != spi) { + cs_deactivate(as, as->stay); + cs_activate(as, spi); + } + as->stay = NULL; + } else + cs_activate(as, spi); + + atmel_spi_next_xfer(master, msg); +} + +/* + * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma: + * - The buffer is either valid for CPU access, else NULL + * - If the buffer is valid, so is its DMA address + * + * This driver manages the dma address unless message->is_dma_mapped. + */ +static int +atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer) +{ + struct device *dev = &as->pdev->dev; + + xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS; + if (xfer->tx_buf) { + /* tx_buf is a const void* where we need a void * for the dma + * mapping */ + void *nonconst_tx = (void *)xfer->tx_buf; + + xfer->tx_dma = dma_map_single(dev, + nonconst_tx, xfer->len, + DMA_TO_DEVICE); + if (dma_mapping_error(dev, xfer->tx_dma)) + return -ENOMEM; + } + if (xfer->rx_buf) { + xfer->rx_dma = dma_map_single(dev, + xfer->rx_buf, xfer->len, + DMA_FROM_DEVICE); + if (dma_mapping_error(dev, xfer->rx_dma)) { + if (xfer->tx_buf) + dma_unmap_single(dev, + xfer->tx_dma, xfer->len, + DMA_TO_DEVICE); + return -ENOMEM; + } + } + return 0; +} + +static void atmel_spi_dma_unmap_xfer(struct spi_master *master, + struct spi_transfer *xfer) +{ + if (xfer->tx_dma != INVALID_DMA_ADDRESS) + dma_unmap_single(master->dev.parent, xfer->tx_dma, + xfer->len, DMA_TO_DEVICE); + if (xfer->rx_dma != INVALID_DMA_ADDRESS) + dma_unmap_single(master->dev.parent, xfer->rx_dma, + xfer->len, DMA_FROM_DEVICE); +} + +static void +atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as, + struct spi_message *msg, int status, int stay) +{ + if (!stay || status < 0) + cs_deactivate(as, msg->spi); + else + as->stay = msg->spi; + + list_del(&msg->queue); + msg->status = status; + + dev_dbg(master->dev.parent, + "xfer complete: %u bytes transferred\n", + msg->actual_length); + + spin_unlock(&as->lock); + msg->complete(msg->context); + spin_lock(&as->lock); + + as->current_transfer = NULL; + as->next_transfer = NULL; + + /* continue if needed */ + if (list_empty(&as->queue) || as->stopping) + spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); + else + atmel_spi_next_message(master); +} + +static irqreturn_t +atmel_spi_interrupt(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct atmel_spi *as = spi_master_get_devdata(master); + struct spi_message *msg; + struct spi_transfer *xfer; + u32 status, pending, imr; + int ret = IRQ_NONE; + + spin_lock(&as->lock); + + xfer = as->current_transfer; + msg = list_entry(as->queue.next, struct spi_message, queue); + + imr = spi_readl(as, IMR); + status = spi_readl(as, SR); + pending = status & imr; + + if (pending & SPI_BIT(OVRES)) { + int timeout; + + ret = IRQ_HANDLED; + + spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) + | SPI_BIT(OVRES))); + + /* + * When we get an overrun, we disregard the current + * transfer. Data will not be copied back from any + * bounce buffer and msg->actual_len will not be + * updated with the last xfer. + * + * We will also not process any remaning transfers in + * the message. + * + * First, stop the transfer and unmap the DMA buffers. + */ + spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); + if (!msg->is_dma_mapped) + atmel_spi_dma_unmap_xfer(master, xfer); + + /* REVISIT: udelay in irq is unfriendly */ + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n", + spi_readl(as, TCR), spi_readl(as, RCR)); + + /* + * Clean up DMA registers and make sure the data + * registers are empty. + */ + spi_writel(as, RNCR, 0); + spi_writel(as, TNCR, 0); + spi_writel(as, RCR, 0); + spi_writel(as, TCR, 0); + for (timeout = 1000; timeout; timeout--) + if (spi_readl(as, SR) & SPI_BIT(TXEMPTY)) + break; + if (!timeout) + dev_warn(master->dev.parent, + "timeout waiting for TXEMPTY"); + while (spi_readl(as, SR) & SPI_BIT(RDRF)) + spi_readl(as, RDR); + + /* Clear any overrun happening while cleaning up */ + spi_readl(as, SR); + + atmel_spi_msg_done(master, as, msg, -EIO, 0); + } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) { + ret = IRQ_HANDLED; + + spi_writel(as, IDR, pending); + + if (as->current_remaining_bytes == 0) { + msg->actual_length += xfer->len; + + if (!msg->is_dma_mapped) + atmel_spi_dma_unmap_xfer(master, xfer); + + /* REVISIT: udelay in irq is unfriendly */ + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + if (atmel_spi_xfer_is_last(msg, xfer)) { + /* report completed message */ + atmel_spi_msg_done(master, as, msg, 0, + xfer->cs_change); + } else { + if (xfer->cs_change) { + cs_deactivate(as, msg->spi); + udelay(1); + cs_activate(as, msg->spi); + } + + /* + * Not done yet. Submit the next transfer. + * + * FIXME handle protocol options for xfer + */ + atmel_spi_next_xfer(master, msg); + } + } else { + /* + * Keep going, we still have data to send in + * the current transfer. + */ + atmel_spi_next_xfer(master, msg); + } + } + + spin_unlock(&as->lock); + + return ret; +} + +static int atmel_spi_setup(struct spi_device *spi) +{ + struct atmel_spi *as; + struct atmel_spi_device *asd; + u32 scbr, csr; + unsigned int bits = spi->bits_per_word; + unsigned long bus_hz; + unsigned int npcs_pin; + int ret; + + as = spi_master_get_devdata(spi->master); + + if (as->stopping) + return -ESHUTDOWN; + + if (spi->chip_select > spi->master->num_chipselect) { + dev_dbg(&spi->dev, + "setup: invalid chipselect %u (%u defined)\n", + spi->chip_select, spi->master->num_chipselect); + return -EINVAL; + } + + if (bits < 8 || bits > 16) { + dev_dbg(&spi->dev, + "setup: invalid bits_per_word %u (8 to 16)\n", + bits); + return -EINVAL; + } + + /* see notes above re chipselect */ + if (!atmel_spi_is_v2() + && spi->chip_select == 0 + && (spi->mode & SPI_CS_HIGH)) { + dev_dbg(&spi->dev, "setup: can't be active-high\n"); + return -EINVAL; + } + + /* v1 chips start out at half the peripheral bus speed. */ + bus_hz = clk_get_rate(as->clk); + if (!atmel_spi_is_v2()) + bus_hz /= 2; + + if (spi->max_speed_hz) { + /* + * Calculate the lowest divider that satisfies the + * constraint, assuming div32/fdiv/mbz == 0. + */ + scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz); + + /* + * If the resulting divider doesn't fit into the + * register bitfield, we can't satisfy the constraint. + */ + if (scbr >= (1 << SPI_SCBR_SIZE)) { + dev_dbg(&spi->dev, + "setup: %d Hz too slow, scbr %u; min %ld Hz\n", + spi->max_speed_hz, scbr, bus_hz/255); + return -EINVAL; + } + } else + /* speed zero means "as slow as possible" */ + scbr = 0xff; + + csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8); + if (spi->mode & SPI_CPOL) + csr |= SPI_BIT(CPOL); + if (!(spi->mode & SPI_CPHA)) + csr |= SPI_BIT(NCPHA); + + /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. + * + * DLYBCT would add delays between words, slowing down transfers. + * It could potentially be useful to cope with DMA bottlenecks, but + * in those cases it's probably best to just use a lower bitrate. + */ + csr |= SPI_BF(DLYBS, 0); + csr |= SPI_BF(DLYBCT, 0); + + /* chipselect must have been muxed as GPIO (e.g. in board setup) */ + npcs_pin = (unsigned int)spi->controller_data; + asd = spi->controller_state; + if (!asd) { + asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL); + if (!asd) + return -ENOMEM; + + ret = gpio_request(npcs_pin, dev_name(&spi->dev)); + if (ret) { + kfree(asd); + return ret; + } + + asd->npcs_pin = npcs_pin; + spi->controller_state = asd; + gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); + } else { + unsigned long flags; + + spin_lock_irqsave(&as->lock, flags); + if (as->stay == spi) + as->stay = NULL; + cs_deactivate(as, spi); + spin_unlock_irqrestore(&as->lock, flags); + } + + asd->csr = csr; + + dev_dbg(&spi->dev, + "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n", + bus_hz / scbr, bits, spi->mode, spi->chip_select, csr); + + if (!atmel_spi_is_v2()) + spi_writel(as, CSR0 + 4 * spi->chip_select, csr); + + return 0; +} + +static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg) +{ + struct atmel_spi *as; + struct spi_transfer *xfer; + unsigned long flags; + struct device *controller = spi->master->dev.parent; + u8 bits; + struct atmel_spi_device *asd; + + as = spi_master_get_devdata(spi->master); + + dev_dbg(controller, "new message %p submitted for %s\n", + msg, dev_name(&spi->dev)); + + if (unlikely(list_empty(&msg->transfers))) + return -EINVAL; + + if (as->stopping) + return -ESHUTDOWN; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) { + dev_dbg(&spi->dev, "missing rx or tx buf\n"); + return -EINVAL; + } + + if (xfer->bits_per_word) { + asd = spi->controller_state; + bits = (asd->csr >> 4) & 0xf; + if (bits != xfer->bits_per_word - 8) { + dev_dbg(&spi->dev, "you can't yet change " + "bits_per_word in transfers\n"); + return -ENOPROTOOPT; + } + } + + /* FIXME implement these protocol options!! */ + if (xfer->speed_hz) { + dev_dbg(&spi->dev, "no protocol options yet\n"); + return -ENOPROTOOPT; + } + + /* + * DMA map early, for performance (empties dcache ASAP) and + * better fault reporting. This is a DMA-only driver. + * + * NOTE that if dma_unmap_single() ever starts to do work on + * platforms supported by this driver, we would need to clean + * up mappings for previously-mapped transfers. + */ + if (!msg->is_dma_mapped) { + if (atmel_spi_dma_map_xfer(as, xfer) < 0) + return -ENOMEM; + } + } + +#ifdef VERBOSE + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + dev_dbg(controller, + " xfer %p: len %u tx %p/%08x rx %p/%08x\n", + xfer, xfer->len, + xfer->tx_buf, xfer->tx_dma, + xfer->rx_buf, xfer->rx_dma); + } +#endif + + msg->status = -EINPROGRESS; + msg->actual_length = 0; + + spin_lock_irqsave(&as->lock, flags); + list_add_tail(&msg->queue, &as->queue); + if (!as->current_transfer) + atmel_spi_next_message(spi->master); + spin_unlock_irqrestore(&as->lock, flags); + + return 0; +} + +static void atmel_spi_cleanup(struct spi_device *spi) +{ + struct atmel_spi *as = spi_master_get_devdata(spi->master); + struct atmel_spi_device *asd = spi->controller_state; + unsigned gpio = (unsigned) spi->controller_data; + unsigned long flags; + + if (!asd) + return; + + spin_lock_irqsave(&as->lock, flags); + if (as->stay == spi) { + as->stay = NULL; + cs_deactivate(as, spi); + } + spin_unlock_irqrestore(&as->lock, flags); + + spi->controller_state = NULL; + gpio_free(gpio); + kfree(asd); +} + +/*-------------------------------------------------------------------------*/ + +static int __init atmel_spi_probe(struct platform_device *pdev) +{ + struct resource *regs; + int irq; + struct clk *clk; + int ret; + struct spi_master *master; + struct atmel_spi *as; + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) + return -ENXIO; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + clk = clk_get(&pdev->dev, "spi_clk"); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + /* setup spi core then atmel-specific driver state */ + ret = -ENOMEM; + master = spi_alloc_master(&pdev->dev, sizeof *as); + if (!master) + goto out_free; + + /* the spi->mode bits understood by this driver: */ + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; + + master->bus_num = pdev->id; + master->num_chipselect = 4; + master->setup = atmel_spi_setup; + master->transfer = atmel_spi_transfer; + master->cleanup = atmel_spi_cleanup; + platform_set_drvdata(pdev, master); + + as = spi_master_get_devdata(master); + + /* + * Scratch buffer is used for throwaway rx and tx data. + * It's coherent to minimize dcache pollution. + */ + as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE, + &as->buffer_dma, GFP_KERNEL); + if (!as->buffer) + goto out_free; + + spin_lock_init(&as->lock); + INIT_LIST_HEAD(&as->queue); + as->pdev = pdev; + as->regs = ioremap(regs->start, resource_size(regs)); + if (!as->regs) + goto out_free_buffer; + as->irq = irq; + as->clk = clk; + + ret = request_irq(irq, atmel_spi_interrupt, 0, + dev_name(&pdev->dev), master); + if (ret) + goto out_unmap_regs; + + /* Initialize the hardware */ + clk_enable(clk); + spi_writel(as, CR, SPI_BIT(SWRST)); + spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS)); + spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); + spi_writel(as, CR, SPI_BIT(SPIEN)); + + /* go! */ + dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", + (unsigned long)regs->start, irq); + + ret = spi_register_master(master); + if (ret) + goto out_reset_hw; + + return 0; + +out_reset_hw: + spi_writel(as, CR, SPI_BIT(SWRST)); + spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + clk_disable(clk); + free_irq(irq, master); +out_unmap_regs: + iounmap(as->regs); +out_free_buffer: + dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer, + as->buffer_dma); +out_free: + clk_put(clk); + spi_master_put(master); + return ret; +} + +static int __exit atmel_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct atmel_spi *as = spi_master_get_devdata(master); + struct spi_message *msg; + + /* reset the hardware and block queue progress */ + spin_lock_irq(&as->lock); + as->stopping = 1; + spi_writel(as, CR, SPI_BIT(SWRST)); + spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ + spi_readl(as, SR); + spin_unlock_irq(&as->lock); + + /* Terminate remaining queued transfers */ + list_for_each_entry(msg, &as->queue, queue) { + /* REVISIT unmapping the dma is a NOP on ARM and AVR32 + * but we shouldn't depend on that... + */ + msg->status = -ESHUTDOWN; + msg->complete(msg->context); + } + + dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer, + as->buffer_dma); + + clk_disable(as->clk); + clk_put(as->clk); + free_irq(as->irq, master); + iounmap(as->regs); + + spi_unregister_master(master); + + return 0; +} + +#ifdef CONFIG_PM + +static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct atmel_spi *as = spi_master_get_devdata(master); + + clk_disable(as->clk); + return 0; +} + +static int atmel_spi_resume(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct atmel_spi *as = spi_master_get_devdata(master); + + clk_enable(as->clk); + return 0; +} + +#else +#define atmel_spi_suspend NULL +#define atmel_spi_resume NULL +#endif + + +static struct platform_driver atmel_spi_driver = { + .driver = { + .name = "atmel_spi", + .owner = THIS_MODULE, + }, + .suspend = atmel_spi_suspend, + .resume = atmel_spi_resume, + .remove = __exit_p(atmel_spi_remove), +}; + +static int __init atmel_spi_init(void) +{ + return platform_driver_probe(&atmel_spi_driver, atmel_spi_probe); +} +module_init(atmel_spi_init); + +static void __exit atmel_spi_exit(void) +{ + platform_driver_unregister(&atmel_spi_driver); +} +module_exit(atmel_spi_exit); + +MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver"); +MODULE_AUTHOR("Haavard Skinnemoen (Atmel)"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:atmel_spi"); |