1 files changed, 203 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/dma.c b/arch/arm/mach-imx/dma.c
new file mode 100644
index 000000000000..71a59e196166
--- /dev/null
+++ b/arch/arm/mach-imx/dma.c
@@ -0,0 +1,203 @@
+/*
+ *  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, disr = DISR;
+        struct dma_channel *channel;
+        unsigned int err_mask = DBTOSR | DRTOSR | DSESR | DBOSR;
+
+        DISR = disr;
+        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);
+                }
+        }
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t
+dma_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
+{
+        int i, disr = DISR;
+
+        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);
+                        }
+                }
+        }
+        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);