--- /dev/null
+/*
+ * linux/arch/arm/mach-imx/dma.c
+ *
+ * imx DMA registration and IRQ dispatching
+ *
+ * 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.
+ *
+ * 03/03/2004 Sascha Hauer <sascha@saschahauer.de>
+ * initial version heavily inspired by
+ * linux/arch/arm/mach-pxa/dma.c
+ */
+
+#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>
+
+static struct dma_channel {
+ char *name;
+ void (*irq_handler) (int, void *, struct pt_regs *);
+ void (*err_handler) (int, void *, struct pt_regs *);
+ void *data;
+} dma_channels[11];
+
+/* set err_handler to NULL to have the standard info-only error handler */
+int
+imx_request_dma(char *name, imx_dma_prio prio,
+ void (*irq_handler) (int, void *, struct pt_regs *),
+ void (*err_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 + (prio == DMA_PRIO_LOW) ? 8 : 4; 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) {
+ DIMR &= ~(1 << i);
+ dma_channels[i].name = name;
+ dma_channels[i].irq_handler = irq_handler;
+ dma_channels[i].err_handler = err_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
+imx_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);
+ DIMR &= ~(1 << dma_ch);
+ dma_channels[dma_ch].name = NULL;
+ local_irq_restore(flags);
+}
+
+static irqreturn_t
+dma_err_handler(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int i;
+ struct dma_channel *channel;
+ unsigned int err_mask = DBTOSR | DRTOSR | DSESR | DBOSR;
+
+ for (i = 0; i < 11; i++) {
+ channel = &dma_channels[i];
+
+ if ( (err_mask & 1<<i) && channel->name && channel->err_handler) {
+ channel->err_handler(i, channel->data, regs);
+ continue;
+ }
+
+ if (DBTOSR & (1 << i)) {
+ printk(KERN_WARNING
+ "Burst timeout on channel %d (%s)\n",
+ i, channel->name);
+ DBTOSR |= (1 << i);
+ }
+ if (DRTOSR & (1 << i)) {
+ printk(KERN_WARNING
+ "Request timeout on channel %d (%s)\n",
+ i, channel->name);
+ DRTOSR |= (1 << i);
+ }
+ if (DSESR & (1 << i)) {
+ printk(KERN_WARNING
+ "Transfer timeout on channel %d (%s)\n",
+ i, channel->name);
+ DSESR |= (1 << i);
+ }
+ if (DBOSR & (1 << i)) {
+ printk(KERN_WARNING
+ "Buffer overflow timeout on channel %d (%s)\n",
+ i, channel->name);
+ DBOSR |= (1 << i);
+ }
+ DISR |= (1 << i);
+ }
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t
+dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int i, disr = DISR;
+
+ for (i = 0; i < 11; i++) {
+ if (disr & (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);
+ DISR |= (1 << i);
+ }
+ }
+ }
+ return IRQ_HANDLED;
+}
+
+static int __init
+imx_dma_init(void)
+{
+ int ret;
+
+ /* reset DMA module */
+ DCR = DCR_DRST;
+
+ ret = request_irq(DMA_INT, dma_irq_handler, 0, "DMA", NULL);
+ if (ret) {
+ printk(KERN_CRIT "Wow! Can't register IRQ for DMA\n");
+ return ret;
+ }
+
+ ret = request_irq(DMA_ERR, dma_err_handler, 0, "DMA", NULL);
+ if (ret) {
+ printk(KERN_CRIT "Wow! Can't register ERRIRQ for DMA\n");
+ free_irq(DMA_INT, NULL);
+ }
+
+ /* enable DMA module */
+ DCR = DCR_DEN;
+
+ /* clear all interrupts */
+ DISR = 0x3ff;
+
+ /* enable interrupts */
+ DIMR = 0;
+
+ return ret;
+}
+
+arch_initcall(imx_dma_init);
+
+EXPORT_SYMBOL(imx_request_dma);
+EXPORT_SYMBOL(imx_free_dma);
git://git.onelab.eu / linux-2.6.git / blobdiff