[RFC 0/3] Add cyclic DMA support to OMAP DMA engine driver
Russell King - ARM Linux
linux at arm.linux.org.uk
Fri Jun 22 05:06:21 EDT 2012
On Fri, Jun 22, 2012 at 09:59:11AM +0100, Russell King - ARM Linux wrote:
> These three patches add support for returning the residue and cyclic DMA
> support to the OMAP DMA engine driver.
>
> As v3.5-rc is horribly broken on my OMAP platforms, I've had to back out
> all the sound/soc/omap changes from the last merge window to test this,
> inspite of Peter Ujfalusi maintaining that there is nothing wrong. I
> can't get working audio support on the OMAP4430SDP any other way.
>
> I am planning no further work on this until OMAP ASoC support gets fixed;
> due to Peter and my plans this summer, this is likely to be late July/
> August time.
>
> This does not implement all of the weird and wonderfully different DMA
> setups which the OMAP ASoC driver appears to support (do we need soo much
> flexibility?) but it does support whatever is required for my OMAP4430SDP
> board.
>
> These patches apply on top of the previously posted series of DMA patches.
Actually, you will need to use this version of the DMA engine driver rather
than the previously posted one - it contains a minor cleanup to allow the
byte size of an element size to be more easily determined:
From: Russell King <rmk+kernel at arm.linux.org.uk>
Subject: [PATCH] dmaengine: add OMAP DMA engine driver
Tested-by: Tony Lindgren <tony at atomide.com>
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
drivers/dma/Kconfig | 6 +
drivers/dma/Makefile | 1 +
drivers/dma/omap-dma.c | 524 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/omap-dma.h | 24 ++
4 files changed, 555 insertions(+), 0 deletions(-)
create mode 100644 drivers/dma/omap-dma.c
create mode 100644 include/linux/omap-dma.h
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index eb2b60e..8be3bf6 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -261,6 +261,12 @@ config DMA_SA11X0
SA-1110 SoCs. This DMA engine can only be used with on-chip
devices.
+config DMA_OMAP
+ tristate "OMAP DMA support"
+ depends on ARCH_OMAP
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+
config DMA_ENGINE
bool
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index fc05f7d..ddc291a 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_PCH_DMA) += pch_dma.o
obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
+obj-$(CONFIG_DMA_OMAP) += omap-dma.o
diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
new file mode 100644
index 0000000..47d5e63
--- /dev/null
+++ b/drivers/dma/omap-dma.c
@@ -0,0 +1,524 @@
+/*
+ * OMAP DMAengine support
+ *
+ * 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/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/omap-dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "virt-dma.h"
+#include <plat/dma.h>
+
+struct omap_dmadev {
+ struct dma_device ddev;
+ spinlock_t lock;
+ struct tasklet_struct task;
+ struct list_head pending;
+};
+
+struct omap_chan {
+ struct virt_dma_chan vc;
+ struct list_head node;
+
+ struct dma_slave_config cfg;
+ unsigned dma_sig;
+
+ int dma_ch;
+ struct omap_desc *desc;
+ unsigned sgidx;
+};
+
+struct omap_sg {
+ dma_addr_t addr;
+ uint32_t en; /* number of elements (24-bit) */
+ uint32_t fn; /* number of frames (16-bit) */
+};
+
+struct omap_desc {
+ struct virt_dma_desc vd;
+ enum dma_transfer_direction dir;
+ dma_addr_t dev_addr;
+
+ uint8_t es; /* element size */
+ uint8_t sync_mode; /* OMAP_DMA_SYNC_xxx */
+ uint8_t sync_type; /* OMAP_DMA_xxx_SYNC* */
+ uint8_t periph_port; /* Peripheral port */
+
+ unsigned sglen;
+ struct omap_sg sg[0];
+};
+
+static const unsigned es_bytes[] = {
+ [OMAP_DMA_DATA_TYPE_S8] = 1,
+ [OMAP_DMA_DATA_TYPE_S16] = 2,
+ [OMAP_DMA_DATA_TYPE_S32] = 4,
+};
+
+static inline struct omap_dmadev *to_omap_dma_dev(struct dma_device *d)
+{
+ return container_of(d, struct omap_dmadev, ddev);
+}
+
+static inline struct omap_chan *to_omap_dma_chan(struct dma_chan *c)
+{
+ return container_of(c, struct omap_chan, vc.chan);
+}
+
+static inline struct omap_desc *to_omap_dma_desc(struct dma_async_tx_descriptor *t)
+{
+ return container_of(t, struct omap_desc, vd.tx);
+}
+
+static void omap_dma_desc_free(struct virt_dma_desc *vd)
+{
+ kfree(container_of(vd, struct omap_desc, vd));
+}
+
+static void omap_dma_start_sg(struct omap_chan *c, struct omap_desc *d,
+ unsigned idx)
+{
+ struct omap_sg *sg = d->sg + idx;
+
+ if (d->dir == DMA_DEV_TO_MEM)
+ omap_set_dma_dest_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
+ OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);
+ else
+ omap_set_dma_src_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
+ OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);
+
+ omap_set_dma_transfer_params(c->dma_ch, d->es, sg->en, sg->fn,
+ d->sync_mode, c->dma_sig, d->sync_type);
+
+ omap_start_dma(c->dma_ch);
+}
+
+static void omap_dma_start_desc(struct omap_chan *c)
+{
+ struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
+ struct omap_desc *d;
+
+ if (!vd) {
+ c->desc = NULL;
+ return;
+ }
+
+ list_del(&vd->node);
+
+ c->desc = d = to_omap_dma_desc(&vd->tx);
+ c->sgidx = 0;
+
+ if (d->dir == DMA_DEV_TO_MEM)
+ omap_set_dma_src_params(c->dma_ch, d->periph_port,
+ OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, 0);
+ else
+ omap_set_dma_dest_params(c->dma_ch, d->periph_port,
+ OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, 0);
+
+ omap_dma_start_sg(c, d, 0);
+}
+
+static void omap_dma_callback(int ch, u16 status, void *data)
+{
+ struct omap_chan *c = data;
+ struct omap_desc *d;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ d = c->desc;
+ if (d) {
+ if (++c->sgidx < d->sglen) {
+ omap_dma_start_sg(c, d, c->sgidx);
+ } else {
+ omap_dma_start_desc(c);
+ vchan_cookie_complete(&d->vd);
+ }
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+/*
+ * This callback schedules all pending channels. We could be more
+ * clever here by postponing allocation of the real DMA channels to
+ * this point, and freeing them when our virtual channel becomes idle.
+ *
+ * We would then need to deal with 'all channels in-use'
+ */
+static void omap_dma_sched(unsigned long data)
+{
+ struct omap_dmadev *d = (struct omap_dmadev *)data;
+ LIST_HEAD(head);
+
+ spin_lock_irq(&d->lock);
+ list_splice_tail_init(&d->pending, &head);
+ spin_unlock_irq(&d->lock);
+
+ while (!list_empty(&head)) {
+ struct omap_chan *c = list_first_entry(&head,
+ struct omap_chan, node);
+
+ spin_lock_irq(&c->vc.lock);
+ list_del_init(&c->node);
+ omap_dma_start_desc(c);
+ spin_unlock_irq(&c->vc.lock);
+ }
+}
+
+static int omap_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct omap_chan *c = to_omap_dma_chan(chan);
+
+ dev_info(c->vc.chan.device->dev, "allocating channel for %u\n", c->dma_sig);
+
+ return omap_request_dma(c->dma_sig, "DMA engine",
+ omap_dma_callback, c, &c->dma_ch);
+}
+
+static void omap_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct omap_chan *c = to_omap_dma_chan(chan);
+
+ vchan_free_chan_resources(&c->vc);
+ omap_free_dma(c->dma_ch);
+
+ dev_info(c->vc.chan.device->dev, "freeing channel for %u\n", c->dma_sig);
+}
+
+static enum dma_status omap_dma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+ /*
+ * FIXME: do we need to return pending bytes?
+ * We have no users of that info at the moment...
+ */
+ return dma_cookie_status(chan, cookie, txstate);
+}
+
+static void omap_dma_issue_pending(struct dma_chan *chan)
+{
+ struct omap_chan *c = to_omap_dma_chan(chan);
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (vchan_issue_pending(&c->vc) && !c->desc) {
+ struct omap_dmadev *d = to_omap_dma_dev(chan->device);
+ spin_lock(&d->lock);
+ if (list_empty(&c->node))
+ list_add_tail(&c->node, &d->pending);
+ spin_unlock(&d->lock);
+ tasklet_schedule(&d->task);
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
+ struct dma_chan *chan, struct scatterlist *sgl, unsigned sglen,
+ enum dma_transfer_direction dir, unsigned long tx_flags, void *context)
+{
+ struct omap_chan *c = to_omap_dma_chan(chan);
+ enum dma_slave_buswidth dev_width;
+ struct scatterlist *sgent;
+ struct omap_desc *d;
+ dma_addr_t dev_addr;
+ unsigned i, j = 0, es, en, frame_bytes, sync_type;
+ u32 burst;
+
+ if (dir == DMA_DEV_TO_MEM) {
+ dev_addr = c->cfg.src_addr;
+ dev_width = c->cfg.src_addr_width;
+ burst = c->cfg.src_maxburst;
+ sync_type = OMAP_DMA_SRC_SYNC;
+ } else if (dir == DMA_MEM_TO_DEV) {
+ dev_addr = c->cfg.dst_addr;
+ dev_width = c->cfg.dst_addr_width;
+ burst = c->cfg.dst_maxburst;
+ sync_type = OMAP_DMA_DST_SYNC;
+ } else {
+ dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
+ return NULL;
+ }
+
+ /* Bus width translates to the element size (ES) */
+ switch (dev_width) {
+ case DMA_SLAVE_BUSWIDTH_1_BYTE:
+ es = OMAP_DMA_DATA_TYPE_S8;
+ break;
+ case DMA_SLAVE_BUSWIDTH_2_BYTES:
+ es = OMAP_DMA_DATA_TYPE_S16;
+ break;
+ case DMA_SLAVE_BUSWIDTH_4_BYTES:
+ es = OMAP_DMA_DATA_TYPE_S32;
+ break;
+ default: /* not reached */
+ return NULL;
+ }
+
+ /* Now allocate and setup the descriptor. */
+ d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
+ if (!d)
+ return NULL;
+
+ d->dir = dir;
+ d->dev_addr = dev_addr;
+ d->es = es;
+ d->sync_mode = OMAP_DMA_SYNC_FRAME;
+ d->sync_type = sync_type;
+ d->periph_port = OMAP_DMA_PORT_TIPB;
+
+ /*
+ * Build our scatterlist entries: each contains the address,
+ * the number of elements (EN) in each frame, and the number of
+ * frames (FN). Number of bytes for this entry = ES * EN * FN.
+ *
+ * Burst size translates to number of elements with frame sync.
+ * Note: DMA engine defines burst to be the number of dev-width
+ * transfers.
+ */
+ en = burst;
+ frame_bytes = es_bytes[es] * en;
+ for_each_sg(sgl, sgent, sglen, i) {
+ d->sg[j].addr = sg_dma_address(sgent);
+ d->sg[j].en = en;
+ d->sg[j].fn = sg_dma_len(sgent) / frame_bytes;
+ j++;
+ }
+
+ d->sglen = j;
+
+ return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
+}
+
+static int omap_dma_slave_config(struct omap_chan *c, struct dma_slave_config *cfg)
+{
+ if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
+ cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
+ return -EINVAL;
+
+ memcpy(&c->cfg, cfg, sizeof(c->cfg));
+
+ return 0;
+}
+
+static int omap_dma_terminate_all(struct omap_chan *c)
+{
+ struct omap_dmadev *d = to_omap_dma_dev(c->vc.chan.device);
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+
+ /* Prevent this channel being scheduled */
+ spin_lock(&d->lock);
+ list_del_init(&c->node);
+ spin_unlock(&d->lock);
+
+ /*
+ * Stop DMA activity: we assume the callback will not be called
+ * after omap_stop_dma() returns (even if it does, it will see
+ * c->desc is NULL and exit.)
+ */
+ if (c->desc) {
+ c->desc = NULL;
+ omap_stop_dma(c->dma_ch);
+ }
+
+ vchan_get_all_descriptors(&c->vc, &head);
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+ vchan_dma_desc_free_list(&c->vc, &head);
+
+ return 0;
+}
+
+static int omap_dma_pause(struct omap_chan *c)
+{
+ /* FIXME: not supported by platform private API */
+ return -EINVAL;
+}
+
+static int omap_dma_resume(struct omap_chan *c)
+{
+ /* FIXME: not supported by platform private API */
+ return -EINVAL;
+}
+
+static int omap_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+ unsigned long arg)
+{
+ struct omap_chan *c = to_omap_dma_chan(chan);
+ int ret;
+
+ switch (cmd) {
+ case DMA_SLAVE_CONFIG:
+ ret = omap_dma_slave_config(c, (struct dma_slave_config *)arg);
+ break;
+
+ case DMA_TERMINATE_ALL:
+ ret = omap_dma_terminate_all(c);
+ break;
+
+ case DMA_PAUSE:
+ ret = omap_dma_pause(c);
+ break;
+
+ case DMA_RESUME:
+ ret = omap_dma_resume(c);
+ break;
+
+ default:
+ ret = -ENXIO;
+ break;
+ }
+
+ return ret;
+}
+
+static int omap_dma_chan_init(struct omap_dmadev *od, int dma_sig)
+{
+ struct omap_chan *c;
+
+ c = kzalloc(sizeof(*c), GFP_KERNEL);
+ if (!c)
+ return -ENOMEM;
+
+ c->dma_sig = dma_sig;
+ c->vc.desc_free = omap_dma_desc_free;
+ vchan_init(&c->vc, &od->ddev);
+ INIT_LIST_HEAD(&c->node);
+
+ od->ddev.chancnt++;
+
+ return 0;
+}
+
+static void omap_dma_free(struct omap_dmadev *od)
+{
+ tasklet_kill(&od->task);
+ while (!list_empty(&od->ddev.channels)) {
+ struct omap_chan *c = list_first_entry(&od->ddev.channels,
+ struct omap_chan, vc.chan.device_node);
+
+ list_del(&c->vc.chan.device_node);
+ tasklet_kill(&c->vc.task);
+ kfree(c);
+ }
+ kfree(od);
+}
+
+static int omap_dma_probe(struct platform_device *pdev)
+{
+ struct omap_dmadev *od;
+ int rc, i;
+
+ od = kzalloc(sizeof(*od), GFP_KERNEL);
+ if (!od)
+ return -ENOMEM;
+
+ dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+ od->ddev.device_alloc_chan_resources = omap_dma_alloc_chan_resources;
+ od->ddev.device_free_chan_resources = omap_dma_free_chan_resources;
+ od->ddev.device_tx_status = omap_dma_tx_status;
+ od->ddev.device_issue_pending = omap_dma_issue_pending;
+ od->ddev.device_prep_slave_sg = omap_dma_prep_slave_sg;
+ od->ddev.device_control = omap_dma_control;
+ od->ddev.dev = &pdev->dev;
+ INIT_LIST_HEAD(&od->ddev.channels);
+ INIT_LIST_HEAD(&od->pending);
+ spin_lock_init(&od->lock);
+
+ tasklet_init(&od->task, omap_dma_sched, (unsigned long)od);
+
+ for (i = 0; i < 127; i++) {
+ rc = omap_dma_chan_init(od, i);
+ if (rc) {
+ omap_dma_free(od);
+ return rc;
+ }
+ }
+
+ rc = dma_async_device_register(&od->ddev);
+ if (rc) {
+ pr_warn("OMAP-DMA: failed to register slave DMA engine device: %d\n",
+ rc);
+ omap_dma_free(od);
+ } else {
+ platform_set_drvdata(pdev, od);
+ }
+
+ dev_info(&pdev->dev, "OMAP DMA engine driver\n");
+
+ return rc;
+}
+
+static int omap_dma_remove(struct platform_device *pdev)
+{
+ struct omap_dmadev *od = platform_get_drvdata(pdev);
+
+ dma_async_device_unregister(&od->ddev);
+ omap_dma_free(od);
+
+ return 0;
+}
+
+static struct platform_driver omap_dma_driver = {
+ .probe = omap_dma_probe,
+ .remove = omap_dma_remove,
+ .driver = {
+ .name = "omap-dma-engine",
+ .owner = THIS_MODULE,
+ },
+};
+
+bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
+{
+ if (chan->device->dev->driver == &omap_dma_driver.driver) {
+ struct omap_chan *c = to_omap_dma_chan(chan);
+ unsigned req = *(unsigned *)param;
+
+ return req == c->dma_sig;
+ }
+ return false;
+}
+EXPORT_SYMBOL_GPL(omap_dma_filter_fn);
+
+static struct platform_device *pdev;
+
+static const struct platform_device_info omap_dma_dev_info = {
+ .name = "omap-dma-engine",
+ .id = -1,
+ .dma_mask = DMA_BIT_MASK(32),
+};
+
+static int omap_dma_init(void)
+{
+ int rc = platform_driver_register(&omap_dma_driver);
+
+ if (rc == 0) {
+ pdev = platform_device_register_full(&omap_dma_dev_info);
+ if (IS_ERR(pdev)) {
+ platform_driver_unregister(&omap_dma_driver);
+ rc = PTR_ERR(pdev);
+ }
+ }
+ return rc;
+}
+subsys_initcall(omap_dma_init);
+
+static void __exit omap_dma_exit(void)
+{
+ platform_device_unregister(pdev);
+ platform_driver_unregister(&omap_dma_driver);
+}
+module_exit(omap_dma_exit);
+
+MODULE_AUTHOR("Russell King");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/omap-dma.h b/include/linux/omap-dma.h
new file mode 100644
index 0000000..869534c
--- /dev/null
+++ b/include/linux/omap-dma.h
@@ -0,0 +1,24 @@
+/*
+ * OMAP DMA Engine support
+ *
+ * Copyright (C) 2012 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.
+ */
+#ifndef __LINUX_OMAP_DMA_H
+#define __LINUX_OMAP_DMA_H
+
+struct dma_chan;
+
+#if defined(CONFIG_DMA_OMAP) || defined(CONFIG_DMA_OMAP_MODULE)
+bool omap_dma_filter_fn(struct dma_chan *, void *);
+#else
+static inline bool omap_dma_filter_fn(struct dma_chan *c, void *d)
+{
+ return false;
+}
+#endif
+
+#endif
--
1.7.4.4
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