aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/kernel/dma.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/kernel/dma.c')
-rw-r--r--arch/arm/kernel/dma.c302
1 files changed, 302 insertions, 0 deletions
diff --git a/arch/arm/kernel/dma.c b/arch/arm/kernel/dma.c
new file mode 100644
index 00000000000..2b788388423
--- /dev/null
+++ b/arch/arm/kernel/dma.c
@@ -0,0 +1,302 @@
+/*
+ * linux/arch/arm/kernel/dma.c
+ *
+ * Copyright (C) 1995-2000 Russell King
+ *
+ * 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.
+ *
+ * Front-end to the DMA handling. This handles the allocation/freeing
+ * of DMA channels, and provides a unified interface to the machines
+ * DMA facilities.
+ */
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mman.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+
+#include <asm/dma.h>
+
+#include <asm/mach/dma.h>
+
+DEFINE_SPINLOCK(dma_spin_lock);
+
+#if MAX_DMA_CHANNELS > 0
+
+static dma_t dma_chan[MAX_DMA_CHANNELS];
+
+/*
+ * Get dma list for /proc/dma
+ */
+int get_dma_list(char *buf)
+{
+ dma_t *dma;
+ char *p = buf;
+ int i;
+
+ for (i = 0, dma = dma_chan; i < MAX_DMA_CHANNELS; i++, dma++)
+ if (dma->lock)
+ p += sprintf(p, "%2d: %14s %s\n", i,
+ dma->d_ops->type, dma->device_id);
+
+ return p - buf;
+}
+
+/*
+ * Request DMA channel
+ *
+ * On certain platforms, we have to allocate an interrupt as well...
+ */
+int request_dma(dmach_t channel, const char *device_id)
+{
+ dma_t *dma = dma_chan + channel;
+ int ret;
+
+ if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
+ goto bad_dma;
+
+ if (xchg(&dma->lock, 1) != 0)
+ goto busy;
+
+ dma->device_id = device_id;
+ dma->active = 0;
+ dma->invalid = 1;
+
+ ret = 0;
+ if (dma->d_ops->request)
+ ret = dma->d_ops->request(channel, dma);
+
+ if (ret)
+ xchg(&dma->lock, 0);
+
+ return ret;
+
+bad_dma:
+ printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel);
+ return -EINVAL;
+
+busy:
+ return -EBUSY;
+}
+
+/*
+ * Free DMA channel
+ *
+ * On certain platforms, we have to free interrupt as well...
+ */
+void free_dma(dmach_t channel)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
+ goto bad_dma;
+
+ if (dma->active) {
+ printk(KERN_ERR "dma%d: freeing active DMA\n", channel);
+ dma->d_ops->disable(channel, dma);
+ dma->active = 0;
+ }
+
+ if (xchg(&dma->lock, 0) != 0) {
+ if (dma->d_ops->free)
+ dma->d_ops->free(channel, dma);
+ return;
+ }
+
+ printk(KERN_ERR "dma%d: trying to free free DMA\n", channel);
+ return;
+
+bad_dma:
+ printk(KERN_ERR "dma: trying to free DMA%d\n", channel);
+}
+
+/* Set DMA Scatter-Gather list
+ */
+void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (dma->active)
+ printk(KERN_ERR "dma%d: altering DMA SG while "
+ "DMA active\n", channel);
+
+ dma->sg = sg;
+ dma->sgcount = nr_sg;
+ dma->using_sg = 1;
+ dma->invalid = 1;
+}
+
+/* Set DMA address
+ *
+ * Copy address to the structure, and set the invalid bit
+ */
+void set_dma_addr (dmach_t channel, unsigned long physaddr)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (dma->active)
+ printk(KERN_ERR "dma%d: altering DMA address while "
+ "DMA active\n", channel);
+
+ dma->sg = &dma->buf;
+ dma->sgcount = 1;
+ dma->buf.__address = bus_to_virt(physaddr);
+ dma->using_sg = 0;
+ dma->invalid = 1;
+}
+
+/* Set DMA byte count
+ *
+ * Copy address to the structure, and set the invalid bit
+ */
+void set_dma_count (dmach_t channel, unsigned long count)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (dma->active)
+ printk(KERN_ERR "dma%d: altering DMA count while "
+ "DMA active\n", channel);
+
+ dma->sg = &dma->buf;
+ dma->sgcount = 1;
+ dma->buf.length = count;
+ dma->using_sg = 0;
+ dma->invalid = 1;
+}
+
+/* Set DMA direction mode
+ */
+void set_dma_mode (dmach_t channel, dmamode_t mode)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (dma->active)
+ printk(KERN_ERR "dma%d: altering DMA mode while "
+ "DMA active\n", channel);
+
+ dma->dma_mode = mode;
+ dma->invalid = 1;
+}
+
+/* Enable DMA channel
+ */
+void enable_dma (dmach_t channel)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (!dma->lock)
+ goto free_dma;
+
+ if (dma->active == 0) {
+ dma->active = 1;
+ dma->d_ops->enable(channel, dma);
+ }
+ return;
+
+free_dma:
+ printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel);
+ BUG();
+}
+
+/* Disable DMA channel
+ */
+void disable_dma (dmach_t channel)
+{
+ dma_t *dma = dma_chan + channel;
+
+ if (!dma->lock)
+ goto free_dma;
+
+ if (dma->active == 1) {
+ dma->active = 0;
+ dma->d_ops->disable(channel, dma);
+ }
+ return;
+
+free_dma:
+ printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel);
+ BUG();
+}
+
+/*
+ * Is the specified DMA channel active?
+ */
+int dma_channel_active(dmach_t channel)
+{
+ return dma_chan[channel].active;
+}
+
+void set_dma_page(dmach_t channel, char pagenr)
+{
+ printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel);
+}
+
+void set_dma_speed(dmach_t channel, int cycle_ns)
+{
+ dma_t *dma = dma_chan + channel;
+ int ret = 0;
+
+ if (dma->d_ops->setspeed)
+ ret = dma->d_ops->setspeed(channel, dma, cycle_ns);
+ dma->speed = ret;
+}
+
+int get_dma_residue(dmach_t channel)
+{
+ dma_t *dma = dma_chan + channel;
+ int ret = 0;
+
+ if (dma->d_ops->residue)
+ ret = dma->d_ops->residue(channel, dma);
+
+ return ret;
+}
+
+void __init init_dma(void)
+{
+ arch_dma_init(dma_chan);
+}
+
+#else
+
+int request_dma(dmach_t channel, const char *device_id)
+{
+ return -EINVAL;
+}
+
+int get_dma_residue(dmach_t channel)
+{
+ return 0;
+}
+
+#define GLOBAL_ALIAS(_a,_b) asm (".set " #_a "," #_b "; .globl " #_a)
+GLOBAL_ALIAS(disable_dma, get_dma_residue);
+GLOBAL_ALIAS(enable_dma, get_dma_residue);
+GLOBAL_ALIAS(free_dma, get_dma_residue);
+GLOBAL_ALIAS(get_dma_list, get_dma_residue);
+GLOBAL_ALIAS(set_dma_mode, get_dma_residue);
+GLOBAL_ALIAS(set_dma_page, get_dma_residue);
+GLOBAL_ALIAS(set_dma_count, get_dma_residue);
+GLOBAL_ALIAS(set_dma_addr, get_dma_residue);
+GLOBAL_ALIAS(set_dma_sg, get_dma_residue);
+GLOBAL_ALIAS(set_dma_speed, get_dma_residue);
+GLOBAL_ALIAS(init_dma, get_dma_residue);
+
+#endif
+
+EXPORT_SYMBOL(request_dma);
+EXPORT_SYMBOL(free_dma);
+EXPORT_SYMBOL(enable_dma);
+EXPORT_SYMBOL(disable_dma);
+EXPORT_SYMBOL(set_dma_addr);
+EXPORT_SYMBOL(set_dma_count);
+EXPORT_SYMBOL(set_dma_mode);
+EXPORT_SYMBOL(set_dma_page);
+EXPORT_SYMBOL(get_dma_residue);
+EXPORT_SYMBOL(set_dma_sg);
+EXPORT_SYMBOL(set_dma_speed);
+
+EXPORT_SYMBOL(dma_spin_lock);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-28 02:08:27 +0000