[ARM] pxa: introduce plat-pxa for PXA common code and add DMA support
1. introduce folder of 'arch/arm/plat-pxa' for common code across different
PXA processor families
2. initially moved DMA code into plat-pxa
3. common code in <mach/dma.h> moved into <plat/dma.h>, new processors
should implement its own <mach/dma.h>, provide the following required
definitions and '#include <plat/dma.h>' in the end:
- DMAC_REGS_VIRT for mapped virtual address of the DMA registers'
physical I/O memory
Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c
new file mode 100644
index 0000000..70aeee4
--- /dev/null
+++ b/arch/arm/plat-pxa/dma.c
@@ -0,0 +1,144 @@
+/*
+ * linux/arch/arm/plat-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 <mach/hardware.h>
+#include <mach/dma.h>
+
+struct dma_channel {
+ char *name;
+ pxa_dma_prio prio;
+ void (*irq_handler)(int, void *);
+ void *data;
+};
+
+static struct dma_channel *dma_channels;
+static int num_dma_channels;
+
+int pxa_request_dma (char *name, pxa_dma_prio prio,
+ void (*irq_handler)(int, void *),
+ void *data)
+{
+ unsigned long flags;
+ int i, found = 0;
+
+ /* basic sanity checks */
+ if (!name || !irq_handler)
+ return -EINVAL;
+
+ local_irq_save(flags);
+
+ do {
+ /* try grabbing a DMA channel with the requested priority */
+ for (i = 0; i < num_dma_channels; i++) {
+ if ((dma_channels[i].prio == prio) &&
+ !dma_channels[i].name) {
+ found = 1;
+ break;
+ }
+ }
+ /* if requested prio group is full, try a hier priority */
+ } while (!found && prio--);
+
+ 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",
+ __func__, 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)
+{
+ int i, dint = DINT;
+
+ for (i = 0; i < num_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);
+ } 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;
+}
+
+int __init pxa_init_dma(int irq, int num_ch)
+{
+ int i, ret;
+
+ dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
+ if (dma_channels == NULL)
+ return -ENOMEM;
+
+ /* dma channel priorities on pxa2xx processors:
+ * ch 0 - 3, 16 - 19 <--> (0) DMA_PRIO_HIGH
+ * ch 4 - 7, 20 - 23 <--> (1) DMA_PRIO_MEDIUM
+ * ch 8 - 15, 24 - 31 <--> (2) DMA_PRIO_LOW
+ */
+ for (i = 0; i < num_ch; i++) {
+ DCSR(i) = 0;
+ dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
+ }
+
+ ret = request_irq(irq, dma_irq_handler, IRQF_DISABLED, "DMA", NULL);
+ if (ret) {
+ printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
+ kfree(dma_channels);
+ return ret;
+ }
+
+ num_dma_channels = num_ch;
+ return 0;
+}
+
+EXPORT_SYMBOL(pxa_request_dma);
+EXPORT_SYMBOL(pxa_free_dma);