diff options
author | Olof Johansson <olof@lixom.net> | 2012-02-07 15:04:15 -0800 |
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committer | Olof Johansson <olof@lixom.net> | 2012-02-07 15:05:20 -0800 |
commit | a5f17d1f4c2831b9b9bf8b1a537cdbac995d6e13 (patch) | |
tree | cce7eab28de00a88d75b8eda704f5838e10947b1 /drivers/tty/serial/8250/8250_fsl.c | |
parent | dcf81c1af839b77b44404453ecae6e5ac5a75f05 (diff) | |
parent | 62aa2b537c6f5957afd98e29f96897419ed5ebab (diff) |
Merge tag 'v3.3-rc2' into depends/rmk/for-armsoc
There were conflicts between fixes going in after 3.3-rc1 and
Russell's stable arm-soc base branch. Resolving it in the dependency
branch so that each topic branch shares the same resolution.
Conflicts:
arch/arm/mach-at91/at91cap9.c
arch/arm/mach-at91/at91sam9g45.c
Diffstat (limited to 'drivers/tty/serial/8250/8250_fsl.c')
-rw-r--r-- | drivers/tty/serial/8250/8250_fsl.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c new file mode 100644 index 00000000000..f4d3c47b88e --- /dev/null +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -0,0 +1,63 @@ +#include <linux/serial_reg.h> +#include <linux/serial_8250.h> + +#include "8250.h" + +/* + * Freescale 16550 UART "driver", Copyright (C) 2011 Paul Gortmaker. + * + * 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. + * + * This isn't a full driver; it just provides an alternate IRQ + * handler to deal with an errata. Everything else is just + * using the bog standard 8250 support. + * + * We follow code flow of serial8250_default_handle_irq() but add + * a check for a break and insert a dummy read on the Rx for the + * immediately following IRQ event. + * + * We re-use the already existing "bug handling" lsr_saved_flags + * field to carry the "what we just did" information from the one + * IRQ event to the next one. + */ + +int fsl8250_handle_irq(struct uart_port *port) +{ + unsigned char lsr, orig_lsr; + unsigned long flags; + unsigned int iir; + struct uart_8250_port *up = + container_of(port, struct uart_8250_port, port); + + spin_lock_irqsave(&up->port.lock, flags); + + iir = port->serial_in(port, UART_IIR); + if (iir & UART_IIR_NO_INT) { + spin_unlock_irqrestore(&up->port.lock, flags); + return 0; + } + + /* This is the WAR; if last event was BRK, then read and return */ + if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) { + up->lsr_saved_flags &= ~UART_LSR_BI; + port->serial_in(port, UART_RX); + spin_unlock_irqrestore(&up->port.lock, flags); + return 1; + } + + lsr = orig_lsr = up->port.serial_in(&up->port, UART_LSR); + + if (lsr & (UART_LSR_DR | UART_LSR_BI)) + lsr = serial8250_rx_chars(up, lsr); + + serial8250_modem_status(up); + + if (lsr & UART_LSR_THRE) + serial8250_tx_chars(up); + + up->lsr_saved_flags = orig_lsr; + spin_unlock_irqrestore(&up->port.lock, flags); + return 1; +} |