summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-sa1100/dma.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mach-sa1100/dma.c')
-rw-r--r--arch/arm/mach-sa1100/dma.c348
1 files changed, 0 insertions, 348 deletions
diff --git a/arch/arm/mach-sa1100/dma.c b/arch/arm/mach-sa1100/dma.c
deleted file mode 100644
index ad66035..0000000
--- a/arch/arm/mach-sa1100/dma.c
+++ /dev/null
@@ -1,348 +0,0 @@
-/*
- * arch/arm/mach-sa1100/dma.c
- *
- * Support functions for the SA11x0 internal DMA channels.
- *
- * Copyright (C) 2000, 2001 by Nicolas Pitre
- *
- * 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/interrupt.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
-#include <linux/errno.h>
-
-#include <asm/system.h>
-#include <asm/irq.h>
-#include <mach/hardware.h>
-#include <mach/dma.h>
-
-
-#undef DEBUG
-#ifdef DEBUG
-#define DPRINTK( s, arg... ) printk( "dma<%p>: " s, regs , ##arg )
-#else
-#define DPRINTK( x... )
-#endif
-
-
-typedef struct {
- const char *device_id; /* device name */
- u_long device; /* this channel device, 0 if unused*/
- dma_callback_t callback; /* to call when DMA completes */
- void *data; /* ... with private data ptr */
-} sa1100_dma_t;
-
-static sa1100_dma_t dma_chan[SA1100_DMA_CHANNELS];
-
-static DEFINE_SPINLOCK(dma_list_lock);
-
-
-static irqreturn_t dma_irq_handler(int irq, void *dev_id)
-{
- dma_regs_t *dma_regs = dev_id;
- sa1100_dma_t *dma = dma_chan + (((u_int)dma_regs >> 5) & 7);
- int status = dma_regs->RdDCSR;
-
- if (status & (DCSR_ERROR)) {
- printk(KERN_CRIT "DMA on \"%s\" caused an error\n", dma->device_id);
- dma_regs->ClrDCSR = DCSR_ERROR;
- }
-
- dma_regs->ClrDCSR = status & (DCSR_DONEA | DCSR_DONEB);
- if (dma->callback) {
- if (status & DCSR_DONEA)
- dma->callback(dma->data);
- if (status & DCSR_DONEB)
- dma->callback(dma->data);
- }
- return IRQ_HANDLED;
-}
-
-
-/**
- * sa1100_request_dma - allocate one of the SA11x0's DMA channels
- * @device: The SA11x0 peripheral targeted by this request
- * @device_id: An ascii name for the claiming device
- * @callback: Function to be called when the DMA completes
- * @data: A cookie passed back to the callback function
- * @dma_regs: Pointer to the location of the allocated channel's identifier
- *
- * This function will search for a free DMA channel and returns the
- * address of the hardware registers for that channel as the channel
- * identifier. This identifier is written to the location pointed by
- * @dma_regs. The list of possible values for @device are listed into
- * arch/arm/mach-sa1100/include/mach/dma.h as a dma_device_t enum.
- *
- * Note that reading from a port and writing to the same port are
- * actually considered as two different streams requiring separate
- * DMA registrations.
- *
- * The @callback function is called from interrupt context when one
- * of the two possible DMA buffers in flight has terminated. That
- * function has to be small and efficient while posponing more complex
- * processing to a lower priority execution context.
- *
- * If no channels are available, or if the desired @device is already in
- * use by another DMA channel, then an error code is returned. This
- * function must be called before any other DMA calls.
- **/
-
-int sa1100_request_dma (dma_device_t device, const char *device_id,
- dma_callback_t callback, void *data,
- dma_regs_t **dma_regs)
-{
- sa1100_dma_t *dma = NULL;
- dma_regs_t *regs;
- int i, err;
-
- *dma_regs = NULL;
-
- err = 0;
- spin_lock(&dma_list_lock);
- for (i = 0; i < SA1100_DMA_CHANNELS; i++) {
- if (dma_chan[i].device == device) {
- err = -EBUSY;
- break;
- } else if (!dma_chan[i].device && !dma) {
- dma = &dma_chan[i];
- }
- }
- if (!err) {
- if (dma)
- dma->device = device;
- else
- err = -ENOSR;
- }
- spin_unlock(&dma_list_lock);
- if (err)
- return err;
-
- i = dma - dma_chan;
- regs = (dma_regs_t *)&DDAR(i);
- err = request_irq(IRQ_DMA0 + i, dma_irq_handler, IRQF_DISABLED,
- device_id, regs);
- if (err) {
- printk(KERN_ERR
- "%s: unable to request IRQ %d for %s\n",
- __func__, IRQ_DMA0 + i, device_id);
- dma->device = 0;
- return err;
- }
-
- *dma_regs = regs;
- dma->device_id = device_id;
- dma->callback = callback;
- dma->data = data;
-
- regs->ClrDCSR =
- (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB |
- DCSR_IE | DCSR_ERROR | DCSR_RUN);
- regs->DDAR = device;
-
- return 0;
-}
-
-
-/**
- * sa1100_free_dma - free a SA11x0 DMA channel
- * @regs: identifier for the channel to free
- *
- * This clears all activities on a given DMA channel and releases it
- * for future requests. The @regs identifier is provided by a
- * successful call to sa1100_request_dma().
- **/
-
-void sa1100_free_dma(dma_regs_t *regs)
-{
- int i;
-
- for (i = 0; i < SA1100_DMA_CHANNELS; i++)
- if (regs == (dma_regs_t *)&DDAR(i))
- break;
- if (i >= SA1100_DMA_CHANNELS) {
- printk(KERN_ERR "%s: bad DMA identifier\n", __func__);
- return;
- }
-
- if (!dma_chan[i].device) {
- printk(KERN_ERR "%s: Trying to free free DMA\n", __func__);
- return;
- }
-
- regs->ClrDCSR =
- (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB |
- DCSR_IE | DCSR_ERROR | DCSR_RUN);
- free_irq(IRQ_DMA0 + i, regs);
- dma_chan[i].device = 0;
-}
-
-
-/**
- * sa1100_start_dma - submit a data buffer for DMA
- * @regs: identifier for the channel to use
- * @dma_ptr: buffer physical (or bus) start address
- * @size: buffer size
- *
- * This function hands the given data buffer to the hardware for DMA
- * access. If another buffer is already in flight then this buffer
- * will be queued so the DMA engine will switch to it automatically
- * when the previous one is done. The DMA engine is actually toggling
- * between two buffers so at most 2 successful calls can be made before
- * one of them terminates and the callback function is called.
- *
- * The @regs identifier is provided by a successful call to
- * sa1100_request_dma().
- *
- * The @size must not be larger than %MAX_DMA_SIZE. If a given buffer
- * is larger than that then it's the caller's responsibility to split
- * it into smaller chunks and submit them separately. If this is the
- * case then a @size of %CUT_DMA_SIZE is recommended to avoid ending
- * up with too small chunks. The callback function can be used to chain
- * submissions of buffer chunks.
- *
- * Error return values:
- * %-EOVERFLOW: Given buffer size is too big.
- * %-EBUSY: Both DMA buffers are already in use.
- * %-EAGAIN: Both buffers were busy but one of them just completed
- * but the interrupt handler has to execute first.
- *
- * This function returs 0 on success.
- **/
-
-int sa1100_start_dma(dma_regs_t *regs, dma_addr_t dma_ptr, u_int size)
-{
- unsigned long flags;
- u_long status;
- int ret;
-
- if (dma_ptr & 3)
- printk(KERN_WARNING "DMA: unaligned start address (0x%08lx)\n",
- (unsigned long)dma_ptr);
-
- if (size > MAX_DMA_SIZE)
- return -EOVERFLOW;
-
- local_irq_save(flags);
- status = regs->RdDCSR;
-
- /* If both DMA buffers are started, there's nothing else we can do. */
- if ((status & (DCSR_STRTA | DCSR_STRTB)) == (DCSR_STRTA | DCSR_STRTB)) {
- DPRINTK("start: st %#x busy\n", status);
- ret = -EBUSY;
- goto out;
- }
-
- if (((status & DCSR_BIU) && (status & DCSR_STRTB)) ||
- (!(status & DCSR_BIU) && !(status & DCSR_STRTA))) {
- if (status & DCSR_DONEA) {
- /* give a chance for the interrupt to be processed */
- ret = -EAGAIN;
- goto out;
- }
- regs->DBSA = dma_ptr;
- regs->DBTA = size;
- regs->SetDCSR = DCSR_STRTA | DCSR_IE | DCSR_RUN;
- DPRINTK("start a=%#x s=%d on A\n", dma_ptr, size);
- } else {
- if (status & DCSR_DONEB) {
- /* give a chance for the interrupt to be processed */
- ret = -EAGAIN;
- goto out;
- }
- regs->DBSB = dma_ptr;
- regs->DBTB = size;
- regs->SetDCSR = DCSR_STRTB | DCSR_IE | DCSR_RUN;
- DPRINTK("start a=%#x s=%d on B\n", dma_ptr, size);
- }
- ret = 0;
-
-out:
- local_irq_restore(flags);
- return ret;
-}
-
-
-/**
- * sa1100_get_dma_pos - return current DMA position
- * @regs: identifier for the channel to use
- *
- * This function returns the current physical (or bus) address for the
- * given DMA channel. If the channel is running i.e. not in a stopped
- * state then the caller must disable interrupts prior calling this
- * function and process the returned value before re-enabling them to
- * prevent races with the completion interrupt handler and the callback
- * function. The validation of the returned value is the caller's
- * responsibility as well -- the hardware seems to return out of range
- * values when the DMA engine completes a buffer.
- *
- * The @regs identifier is provided by a successful call to
- * sa1100_request_dma().
- **/
-
-dma_addr_t sa1100_get_dma_pos(dma_regs_t *regs)
-{
- int status;
-
- /*
- * We must determine whether buffer A or B is active.
- * Two possibilities: either we are in the middle of
- * a buffer, or the DMA controller just switched to the
- * next toggle but the interrupt hasn't been serviced yet.
- * The former case is straight forward. In the later case,
- * we'll do like if DMA is just at the end of the previous
- * toggle since all registers haven't been reset yet.
- * This goes around the edge case and since we're always
- * a little behind anyways it shouldn't make a big difference.
- * If DMA has been stopped prior calling this then the
- * position is exact.
- */
- status = regs->RdDCSR;
- if ((!(status & DCSR_BIU) && (status & DCSR_STRTA)) ||
- ( (status & DCSR_BIU) && !(status & DCSR_STRTB)))
- return regs->DBSA;
- else
- return regs->DBSB;
-}
-
-
-/**
- * sa1100_reset_dma - reset a DMA channel
- * @regs: identifier for the channel to use
- *
- * This function resets and reconfigure the given DMA channel. This is
- * particularly useful after a sleep/wakeup event.
- *
- * The @regs identifier is provided by a successful call to
- * sa1100_request_dma().
- **/
-
-void sa1100_reset_dma(dma_regs_t *regs)
-{
- int i;
-
- for (i = 0; i < SA1100_DMA_CHANNELS; i++)
- if (regs == (dma_regs_t *)&DDAR(i))
- break;
- if (i >= SA1100_DMA_CHANNELS) {
- printk(KERN_ERR "%s: bad DMA identifier\n", __func__);
- return;
- }
-
- regs->ClrDCSR =
- (DCSR_DONEA | DCSR_DONEB | DCSR_STRTA | DCSR_STRTB |
- DCSR_IE | DCSR_ERROR | DCSR_RUN);
- regs->DDAR = dma_chan[i].device;
-}
-
-
-EXPORT_SYMBOL(sa1100_request_dma);
-EXPORT_SYMBOL(sa1100_free_dma);
-EXPORT_SYMBOL(sa1100_start_dma);
-EXPORT_SYMBOL(sa1100_get_dma_pos);
-EXPORT_SYMBOL(sa1100_reset_dma);
-