1 files changed, 386 insertions, 0 deletions
diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c
new file mode 100644
index 000000000..d92f07f6e
--- /dev/null
+++ b/arch/arm/plat-pxa/dma.c
@@ -0,0 +1,386 @@
+/*
+ *  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/slab.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/irq.h>
+#include <asm/memory.h>
+#include <mach/hardware.h>
+#include <mach/dma.h>
+
+#define DMA_DEBUG_NAME		"pxa_dma"
+#define DMA_MAX_REQUESTERS	64
+
+struct dma_channel {
+	char *name;
+	pxa_dma_prio prio;
+	void (*irq_handler)(int, void *);
+	void *data;
+	spinlock_t lock;
+};
+
+static struct dma_channel *dma_channels;
+static int num_dma_channels;
+
+/*
+ * Debug fs
+ */
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
+static struct dentry *dbgfs_root, *dbgfs_state, **dbgfs_chan;
+
+static int dbg_show_requester_chan(struct seq_file *s, void *p)
+{
+	int chan = (int)s->private;
+	int i;
+	u32 drcmr;
+
+	seq_printf(s, "DMA channel %d requesters list :\n", chan);
+	for (i = 0; i < DMA_MAX_REQUESTERS; i++) {
+		drcmr = DRCMR(i);
+		if ((drcmr & DRCMR_CHLNUM) == chan)
+			seq_printf(s, "\tRequester %d (MAPVLD=%d)\n",
+				   i, !!(drcmr & DRCMR_MAPVLD));
+	}
+
+	return 0;
+}
+
+static inline int dbg_burst_from_dcmd(u32 dcmd)
+{
+	int burst = (dcmd >> 16) & 0x3;
+
+	return burst ? 4 << burst : 0;
+}
+
+static int is_phys_valid(unsigned long addr)
+{
+	return pfn_valid(__phys_to_pfn(addr));
+}
+
+#define DCSR_STR(flag) (dcsr & DCSR_##flag ? #flag" " : "")
+#define DCMD_STR(flag) (dcmd & DCMD_##flag ? #flag" " : "")
+
+static int dbg_show_descriptors(struct seq_file *s, void *p)
+{
+	int chan = (int)s->private;
+	int i, max_show = 20, burst, width;
+	u32 dcmd;
+	unsigned long phys_desc;
+	struct pxa_dma_desc *desc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dma_channels[chan].lock, flags);
+	phys_desc = DDADR(chan);
+
+	seq_printf(s, "DMA channel %d descriptors :\n", chan);
+	seq_printf(s, "[%03d] First descriptor unknown\n", 0);
+	for (i = 1; i < max_show && is_phys_valid(phys_desc); i++) {
+		desc = phys_to_virt(phys_desc);
+		dcmd = desc->dcmd;
+		burst = dbg_burst_from_dcmd(dcmd);
+		width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
+
+		seq_printf(s, "[%03d] Desc at %08lx(virt %p)\n",
+			   i, phys_desc, desc);
+		seq_printf(s, "\tDDADR = %08x\n", desc->ddadr);
+		seq_printf(s, "\tDSADR = %08x\n", desc->dsadr);
+		seq_printf(s, "\tDTADR = %08x\n", desc->dtadr);
+		seq_printf(s, "\tDCMD  = %08x (%s%s%s%s%s%s%sburst=%d width=%d len=%d)\n",
+			   dcmd,
+			   DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
+			   DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
+			   DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
+			   DCMD_STR(ENDIAN), burst, width,
+			   dcmd & DCMD_LENGTH);
+		phys_desc = desc->ddadr;
+	}
+	if (i == max_show)
+		seq_printf(s, "[%03d] Desc at %08lx ... max display reached\n",
+			   i, phys_desc);
+	else
+		seq_printf(s, "[%03d] Desc at %08lx is %s\n",
+			   i, phys_desc, phys_desc == DDADR_STOP ?
+			   "DDADR_STOP" : "invalid");
+
+	spin_unlock_irqrestore(&dma_channels[chan].lock, flags);
+
+	return 0;
+}
+
+static int dbg_show_chan_state(struct seq_file *s, void *p)
+{
+	int chan = (int)s->private;
+	u32 dcsr, dcmd;
+	int burst, width;
+	static char *str_prio[] = { "high", "normal", "low" };
+
+	dcsr = DCSR(chan);
+	dcmd = DCMD(chan);
+	burst = dbg_burst_from_dcmd(dcmd);
+	width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
+
+	seq_printf(s, "DMA channel %d\n", chan);
+	seq_printf(s, "\tPriority : %s\n", str_prio[dma_channels[chan].prio]);
+	seq_printf(s, "\tUnaligned transfer bit: %s\n",
+		   DALGN & (1 << chan) ? "yes" : "no");
+	seq_printf(s, "\tDCSR  = %08x (%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s)\n",
+		   dcsr, DCSR_STR(RUN), DCSR_STR(NODESC),
+		   DCSR_STR(STOPIRQEN), DCSR_STR(EORIRQEN),
+		   DCSR_STR(EORJMPEN), DCSR_STR(EORSTOPEN),
+		   DCSR_STR(SETCMPST), DCSR_STR(CLRCMPST),
+		   DCSR_STR(CMPST), DCSR_STR(EORINTR), DCSR_STR(REQPEND),
+		   DCSR_STR(STOPSTATE), DCSR_STR(ENDINTR),
+		   DCSR_STR(STARTINTR), DCSR_STR(BUSERR));
+
+	seq_printf(s, "\tDCMD  = %08x (%s%s%s%s%s%s%sburst=%d width=%d len=%d)\n",
+		   dcmd,
+		   DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
+		   DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
+		   DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
+		   DCMD_STR(ENDIAN), burst, width, dcmd & DCMD_LENGTH);
+	seq_printf(s, "\tDSADR = %08x\n", DSADR(chan));
+	seq_printf(s, "\tDTADR = %08x\n", DTADR(chan));
+	seq_printf(s, "\tDDADR = %08x\n", DDADR(chan));
+
+	return 0;
+}
+
+static int dbg_show_state(struct seq_file *s, void *p)
+{
+	/* basic device status */
+	seq_puts(s, "DMA engine status\n");
+	seq_printf(s, "\tChannel number: %d\n", num_dma_channels);
+
+	return 0;
+}
+
+#define DBGFS_FUNC_DECL(name) \
+static int dbg_open_##name(struct inode *inode, struct file *file) \
+{ \
+	return single_open(file, dbg_show_##name, inode->i_private); \
+} \
+static const struct file_operations dbg_fops_##name = { \
+	.owner		= THIS_MODULE, \
+	.open		= dbg_open_##name, \
+	.llseek		= seq_lseek, \
+	.read		= seq_read, \
+	.release	= single_release, \
+}
+
+DBGFS_FUNC_DECL(state);
+DBGFS_FUNC_DECL(chan_state);
+DBGFS_FUNC_DECL(descriptors);
+DBGFS_FUNC_DECL(requester_chan);
+
+static struct dentry *pxa_dma_dbg_alloc_chan(int ch, struct dentry *chandir)
+{
+	char chan_name[11];
+	struct dentry *chan, *chan_state = NULL, *chan_descr = NULL;
+	struct dentry *chan_reqs = NULL;
+	void *dt;
+
+	scnprintf(chan_name, sizeof(chan_name), "%d", ch);
+	chan = debugfs_create_dir(chan_name, chandir);
+	dt = (void *)ch;
+
+	if (chan)
+		chan_state = debugfs_create_file("state", 0400, chan, dt,
+						 &dbg_fops_chan_state);
+	if (chan_state)
+		chan_descr = debugfs_create_file("descriptors", 0400, chan, dt,
+						 &dbg_fops_descriptors);
+	if (chan_descr)
+		chan_reqs = debugfs_create_file("requesters", 0400, chan, dt,
+						&dbg_fops_requester_chan);
+	if (!chan_reqs)
+		goto err_state;
+
+	return chan;
+
+err_state:
+	debugfs_remove_recursive(chan);
+	return NULL;
+}
+
+static void pxa_dma_init_debugfs(void)
+{
+	int i;
+	struct dentry *chandir;
+
+	dbgfs_root = debugfs_create_dir(DMA_DEBUG_NAME, NULL);
+	if (IS_ERR(dbgfs_root) || !dbgfs_root)
+		goto err_root;
+
+	dbgfs_state = debugfs_create_file("state", 0400, dbgfs_root, NULL,
+					  &dbg_fops_state);
+	if (!dbgfs_state)
+		goto err_state;
+
+	dbgfs_chan = kmalloc(sizeof(*dbgfs_state) * num_dma_channels,
+			     GFP_KERNEL);
+	if (!dbgfs_chan)
+		goto err_alloc;
+
+	chandir = debugfs_create_dir("channels", dbgfs_root);
+	if (!chandir)
+		goto err_chandir;
+
+	for (i = 0; i < num_dma_channels; i++) {
+		dbgfs_chan[i] = pxa_dma_dbg_alloc_chan(i, chandir);
+		if (!dbgfs_chan[i])
+			goto err_chans;
+	}
+
+	return;
+err_chans:
+err_chandir:
+	kfree(dbgfs_chan);
+err_alloc:
+err_state:
+	debugfs_remove_recursive(dbgfs_root);
+err_root:
+	pr_err("pxa_dma: debugfs is not available\n");
+}
+
+static void __exit pxa_dma_cleanup_debugfs(void)
+{
+	debugfs_remove_recursive(dbgfs_root);
+}
+#else
+static inline void pxa_dma_init_debugfs(void) {}
+static inline void pxa_dma_cleanup_debugfs(void) {}
+#endif
+
+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;
+}
+EXPORT_SYMBOL(pxa_request_dma);
+
+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);
+}
+EXPORT_SYMBOL(pxa_free_dma);
+
+static irqreturn_t dma_irq_handler(int irq, void *dev_id)
+{
+	int i, dint = DINT;
+	struct dma_channel *channel;
+
+	while (dint) {
+		i = __ffs(dint);
+		dint &= (dint - 1);
+		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);
+		spin_lock_init(&dma_channels[i].lock);
+	}
+
+	ret = request_irq(irq, dma_irq_handler, 0, "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;
+
+	pxa_dma_init_debugfs();
+
+	return 0;
+}