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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 00:20:36 +0200 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-pxa/dma.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mach-pxa/dma.c')
-rw-r--r-- | arch/arm/mach-pxa/dma.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/dma.c b/arch/arm/mach-pxa/dma.c new file mode 100644 index 000000000000..458112b21e25 --- /dev/null +++ b/arch/arm/mach-pxa/dma.c @@ -0,0 +1,133 @@ +/* + * linux/arch/arm/mach-pxa/dma.c + * + * PXA DMA registration and IRQ dispatching + * + * Author: Nicolas Pitre + * Created: Nov 15, 2001 + * Copyright: MontaVista Software Inc. + * + * 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/module.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/errno.h> + +#include <asm/system.h> +#include <asm/irq.h> +#include <asm/hardware.h> +#include <asm/dma.h> + +#include <asm/arch/pxa-regs.h> + +static struct dma_channel { + char *name; + void (*irq_handler)(int, void *, struct pt_regs *); + void *data; +} dma_channels[PXA_DMA_CHANNELS]; + + +int pxa_request_dma (char *name, pxa_dma_prio prio, + void (*irq_handler)(int, void *, struct pt_regs *), + void *data) +{ + unsigned long flags; + int i, found = 0; + + /* basic sanity checks */ + if (!name || !irq_handler) + return -EINVAL; + + local_irq_save(flags); + + /* try grabbing a DMA channel with the requested priority */ + for (i = prio; i < prio + PXA_DMA_NBCH(prio); i++) { + if (!dma_channels[i].name) { + found = 1; + break; + } + } + + if (!found) { + /* requested prio group is full, try hier priorities */ + for (i = prio-1; i >= 0; i--) { + if (!dma_channels[i].name) { + found = 1; + break; + } + } + } + + if (found) { + DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; + dma_channels[i].name = name; + dma_channels[i].irq_handler = irq_handler; + dma_channels[i].data = data; + } else { + printk (KERN_WARNING "No more available DMA channels for %s\n", name); + i = -ENODEV; + } + + local_irq_restore(flags); + return i; +} + +void pxa_free_dma (int dma_ch) +{ + unsigned long flags; + + if (!dma_channels[dma_ch].name) { + printk (KERN_CRIT + "%s: trying to free channel %d which is already freed\n", + __FUNCTION__, dma_ch); + return; + } + + local_irq_save(flags); + DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; + dma_channels[dma_ch].name = NULL; + local_irq_restore(flags); +} + +static irqreturn_t dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs) +{ + int i, dint = DINT; + + for (i = 0; i < PXA_DMA_CHANNELS; i++) { + if (dint & (1 << i)) { + struct dma_channel *channel = &dma_channels[i]; + if (channel->name && channel->irq_handler) { + channel->irq_handler(i, channel->data, regs); + } else { + /* + * IRQ for an unregistered DMA channel: + * let's clear the interrupts and disable it. + */ + printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i); + DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; + } + } + } + return IRQ_HANDLED; +} + +static int __init pxa_dma_init (void) +{ + int ret; + + ret = request_irq (IRQ_DMA, dma_irq_handler, 0, "DMA", NULL); + if (ret) + printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n"); + return ret; +} + +arch_initcall(pxa_dma_init); + +EXPORT_SYMBOL(pxa_request_dma); +EXPORT_SYMBOL(pxa_free_dma); + |