From 8d160027ff234bddea627ba54c2b85efa1884867 Mon Sep 17 00:00:00 2001 From: Mark Salter Date: Wed, 12 Dec 2012 15:36:38 +0000 Subject: [PATCH] MN10300: fix serial port vdma irq setup for SMP The builtin SoC serial ports have no FIFOs and use a virtual DMA mechanism based on high priority IRQs to avoid overruns. These high priority interrupts are pinned to cpu#0 on SMP systems. This patch fixes a problem with SMP where the set_intr_level() interface is used to set the priority for these IRQs. The set_intr_level() function sets priority on the local cpu but on SMP systems, this code may be run on some other cpu than the one handling the interrupts. Instead of setting interrupt level explicitly, this patch uses a special irq_chip for these interrupts so that the mask/unmask methods can set the interrupt level implicitly. Signed-off-by: Mark Salter Signed-off-by: David Howells --- arch/mn10300/kernel/mn10300-serial.c | 34 ++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c index 4968cfe66c06..cac0f0da9203 100644 --- a/arch/mn10300/kernel/mn10300-serial.c +++ b/arch/mn10300/kernel/mn10300-serial.c @@ -408,6 +408,34 @@ static struct irq_chip mn10300_serial_pic = { .irq_unmask = mn10300_serial_nop, }; +static void mn10300_serial_low_mask(struct irq_data *d) +{ + unsigned long flags; + u16 tmp; + + flags = arch_local_cli_save(); + GxICR(d->irq) = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL); + tmp = GxICR(d->irq); /* flush write buffer */ + arch_local_irq_restore(flags); +} + +static void mn10300_serial_low_unmask(struct irq_data *d) +{ + unsigned long flags; + u16 tmp; + + flags = arch_local_cli_save(); + GxICR(d->irq) = + NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) | GxICR_ENABLE; + tmp = GxICR(d->irq); /* flush write buffer */ + arch_local_irq_restore(flags); +} + +static struct irq_chip mn10300_serial_low_pic = { + .name = "mnserial-low", + .irq_mask = mn10300_serial_low_mask, + .irq_unmask = mn10300_serial_low_unmask, +}; /* * serial virtual DMA interrupt jump table @@ -929,10 +957,8 @@ static int mn10300_serial_startup(struct uart_port *_port) pint->port = port; pint->vdma = mn10300_serial_vdma_tx_handler; - set_intr_level(port->rx_irq, - NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL)); - set_intr_level(port->tx_irq, - NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL)); + irq_set_chip(port->rx_irq, &mn10300_serial_low_pic); + irq_set_chip(port->tx_irq, &mn10300_serial_low_pic); irq_set_chip(port->tm_irq, &mn10300_serial_pic); if (request_irq(port->rx_irq, mn10300_serial_interrupt,