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);
+