From 0fabe1021f8bc9cffdede4ddad0dd04d43c5166c Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Sun, 22 Sep 2013 21:55:19 +0100 Subject: [PATCH] MIPS: DECstation I/O ASIC DMA interrupt classes This change complements commits d0da7c002f7b2a93582187a9e3f73891a01d8ee4 [MIPS: DEC: Convert to new irq_chip functions] and 5359b938c088423a28c41499f183cd10824c1816 [MIPS: DECstation I/O ASIC DMA interrupt handling fix] and implements automatic handling of the two classes of DMA interrupts the I/O ASIC implements, informational and errors. Informational DMA interrupts do not stop the transfer and use the `handle_edge_irq' handler that clears the request right away so that another request may be recorded while the previous is being handled. DMA error interrupts stop the transfer and require a corrective action before DMA can be reenabled. Therefore they use the `handle_fasteoi_irq' handler that only clears the request on the way out. Because MIPS processor interrupt inputs, one of which the I/O ASIC's interrupt controller is cascaded to, are level-triggered it is recommended that error DMA interrupt action handlers are registered with the IRQF_ONESHOT flag set so that they are run with the interrupt line masked. This change removes the export of clear_ioasic_dma_irq that now does not have to be called by device drivers to clear interrupts explicitly anymore. Originally these interrupts were cleared in the .end handler of the `irq_chip' structure, before it was removed. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5874/ Signed-off-by: Ralf Baechle --- arch/mips/dec/ioasic-irq.c | 43 +++++++++++++++++++++++++---- arch/mips/include/asm/dec/ioasic.h | 2 -- drivers/net/ethernet/amd/declance.c | 3 +- 3 files changed, 38 insertions(+), 10 deletions(-) diff --git a/arch/mips/dec/ioasic-irq.c b/arch/mips/dec/ioasic-irq.c index 4b3e3a4375a6..e04d973ce5aa 100644 --- a/arch/mips/dec/ioasic-irq.c +++ b/arch/mips/dec/ioasic-irq.c @@ -1,7 +1,7 @@ /* * DEC I/O ASIC interrupts. * - * Copyright (c) 2002, 2003 Maciej W. Rozycki + * Copyright (c) 2002, 2003, 2013 Maciej W. Rozycki * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -51,22 +51,51 @@ static struct irq_chip ioasic_irq_type = { .irq_unmask = unmask_ioasic_irq, }; -void clear_ioasic_dma_irq(unsigned int irq) +static void clear_ioasic_dma_irq(struct irq_data *d) { u32 sir; - sir = ~(1 << (irq - ioasic_irq_base)); + sir = ~(1 << (d->irq - ioasic_irq_base)); ioasic_write(IO_REG_SIR, sir); + fast_iob(); } static struct irq_chip ioasic_dma_irq_type = { .name = "IO-ASIC-DMA", - .irq_ack = ack_ioasic_irq, + .irq_ack = clear_ioasic_dma_irq, .irq_mask = mask_ioasic_irq, - .irq_mask_ack = ack_ioasic_irq, .irq_unmask = unmask_ioasic_irq, + .irq_eoi = clear_ioasic_dma_irq, }; +/* + * I/O ASIC implements two kinds of DMA interrupts, informational and + * error interrupts. + * + * The formers do not stop DMA and should be cleared as soon as possible + * so that if they retrigger before the handler has completed, usually as + * a side effect of actions taken by the handler, then they are reissued. + * These use the `handle_edge_irq' handler that clears the request right + * away. + * + * The latters stop DMA and do not resume it until the interrupt has been + * cleared. This cannot be done until after a corrective action has been + * taken and this also means they will not retrigger. Therefore they use + * the `handle_fasteoi_irq' handler that only clears the request on the + * way out. Because MIPS processor interrupt inputs, one of which the I/O + * ASIC is cascaded to, are level-triggered it is recommended that error + * DMA interrupt action handlers are registered with the IRQF_ONESHOT flag + * set so that they are run with the interrupt line masked. + * + * This mask has `1' bits in the positions of informational interrupts. + */ +#define IO_IRQ_DMA_INFO \ + (IO_IRQ_MASK(IO_INR_SCC0A_RXDMA) | \ + IO_IRQ_MASK(IO_INR_SCC1A_RXDMA) | \ + IO_IRQ_MASK(IO_INR_ISDN_TXDMA) | \ + IO_IRQ_MASK(IO_INR_ISDN_RXDMA) | \ + IO_IRQ_MASK(IO_INR_ASC_DMA)) + void __init init_ioasic_irqs(int base) { int i; @@ -79,7 +108,9 @@ void __init init_ioasic_irqs(int base) irq_set_chip_and_handler(i, &ioasic_irq_type, handle_level_irq); for (; i < base + IO_IRQ_LINES; i++) - irq_set_chip(i, &ioasic_dma_irq_type); + irq_set_chip_and_handler(i, &ioasic_dma_irq_type, + 1 << (i - base) & IO_IRQ_DMA_INFO ? + handle_edge_irq : handle_fasteoi_irq); ioasic_irq_base = base; } diff --git a/arch/mips/include/asm/dec/ioasic.h b/arch/mips/include/asm/dec/ioasic.h index a6e505a0e44b..be4d62a5a10e 100644 --- a/arch/mips/include/asm/dec/ioasic.h +++ b/arch/mips/include/asm/dec/ioasic.h @@ -31,8 +31,6 @@ static inline u32 ioasic_read(unsigned int reg) return ioasic_base[reg / 4]; } -extern void clear_ioasic_dma_irq(unsigned int irq); - extern void init_ioasic_irqs(int base); extern int dec_ioasic_clocksource_init(void); diff --git a/drivers/net/ethernet/amd/declance.c b/drivers/net/ethernet/amd/declance.c index 94edc9c6fbbf..1b89f1a9127e 100644 --- a/drivers/net/ethernet/amd/declance.c +++ b/drivers/net/ethernet/amd/declance.c @@ -725,7 +725,6 @@ static irqreturn_t lance_dma_merr_int(int irq, void *dev_id) { struct net_device *dev = dev_id; - clear_ioasic_dma_irq(irq); printk(KERN_ERR "%s: DMA error\n", dev->name); return IRQ_HANDLED; } @@ -812,7 +811,7 @@ static int lance_open(struct net_device *dev) if (lp->dma_irq >= 0) { unsigned long flags; - if (request_irq(lp->dma_irq, lance_dma_merr_int, 0, + if (request_irq(lp->dma_irq, lance_dma_merr_int, IRQF_ONESHOT, "lance error", dev)) { free_irq(dev->irq, dev); printk("%s: Can't get DMA IRQ %d\n", dev->name, -- GitLab