[PATCH v3 2/3] mmc: davinci_mmc: convert to DMA engine API
Matt Porter
mporter at ti.com
Wed Aug 22 21:09:35 EDT 2012
Removes use of the DaVinci EDMA private DMA API and replaces
it with use of the DMA engine API.
Signed-off-by: Matt Porter <mporter at ti.com>
---
drivers/mmc/host/davinci_mmc.c | 271 ++++++++++++----------------------------
1 file changed, 82 insertions(+), 189 deletions(-)
diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 7cf6c62..c5e1eeb 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -30,11 +30,12 @@
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/delay.h>
+#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
+#include <linux/edma.h>
#include <linux/mmc/mmc.h>
#include <mach/mmc.h>
-#include <mach/edma.h>
/*
* Register Definitions
@@ -200,21 +201,13 @@ struct mmc_davinci_host {
u32 bytes_left;
u32 rxdma, txdma;
+ struct dma_chan *dma_tx;
+ struct dma_chan *dma_rx;
bool use_dma;
bool do_dma;
bool sdio_int;
bool active_request;
- /* Scatterlist DMA uses one or more parameter RAM entries:
- * the main one (associated with rxdma or txdma) plus zero or
- * more links. The entries for a given transfer differ only
- * by memory buffer (address, length) and link field.
- */
- struct edmacc_param tx_template;
- struct edmacc_param rx_template;
- unsigned n_link;
- u32 links[MAX_NR_SG - 1];
-
/* For PIO we walk scatterlists one segment at a time. */
unsigned int sg_len;
struct scatterlist *sg;
@@ -410,153 +403,74 @@ static void mmc_davinci_start_command(struct mmc_davinci_host *host,
static void davinci_abort_dma(struct mmc_davinci_host *host)
{
- int sync_dev;
+ struct dma_chan *sync_dev;
if (host->data_dir == DAVINCI_MMC_DATADIR_READ)
- sync_dev = host->rxdma;
+ sync_dev = host->dma_rx;
else
- sync_dev = host->txdma;
-
- edma_stop(sync_dev);
- edma_clean_channel(sync_dev);
-}
-
-static void
-mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data);
-
-static void mmc_davinci_dma_cb(unsigned channel, u16 ch_status, void *data)
-{
- if (DMA_COMPLETE != ch_status) {
- struct mmc_davinci_host *host = data;
-
- /* Currently means: DMA Event Missed, or "null" transfer
- * request was seen. In the future, TC errors (like bad
- * addresses) might be presented too.
- */
- dev_warn(mmc_dev(host->mmc), "DMA %s error\n",
- (host->data->flags & MMC_DATA_WRITE)
- ? "write" : "read");
- host->data->error = -EIO;
- mmc_davinci_xfer_done(host, host->data);
- }
-}
-
-/* Set up tx or rx template, to be modified and updated later */
-static void __init mmc_davinci_dma_setup(struct mmc_davinci_host *host,
- bool tx, struct edmacc_param *template)
-{
- unsigned sync_dev;
- const u16 acnt = 4;
- const u16 bcnt = rw_threshold >> 2;
- const u16 ccnt = 0;
- u32 src_port = 0;
- u32 dst_port = 0;
- s16 src_bidx, dst_bidx;
- s16 src_cidx, dst_cidx;
-
- /*
- * A-B Sync transfer: each DMA request is for one "frame" of
- * rw_threshold bytes, broken into "acnt"-size chunks repeated
- * "bcnt" times. Each segment needs "ccnt" such frames; since
- * we tell the block layer our mmc->max_seg_size limit, we can
- * trust (later) that it's within bounds.
- *
- * The FIFOs are read/written in 4-byte chunks (acnt == 4) and
- * EDMA will optimize memory operations to use larger bursts.
- */
- if (tx) {
- sync_dev = host->txdma;
-
- /* src_prt, ccnt, and link to be set up later */
- src_bidx = acnt;
- src_cidx = acnt * bcnt;
-
- dst_port = host->mem_res->start + DAVINCI_MMCDXR;
- dst_bidx = 0;
- dst_cidx = 0;
- } else {
- sync_dev = host->rxdma;
-
- src_port = host->mem_res->start + DAVINCI_MMCDRR;
- src_bidx = 0;
- src_cidx = 0;
-
- /* dst_prt, ccnt, and link to be set up later */
- dst_bidx = acnt;
- dst_cidx = acnt * bcnt;
- }
-
- /*
- * We can't use FIFO mode for the FIFOs because MMC FIFO addresses
- * are not 256-bit (32-byte) aligned. So we use INCR, and the W8BIT
- * parameter is ignored.
- */
- edma_set_src(sync_dev, src_port, INCR, W8BIT);
- edma_set_dest(sync_dev, dst_port, INCR, W8BIT);
+ sync_dev = host->dma_tx;
- edma_set_src_index(sync_dev, src_bidx, src_cidx);
- edma_set_dest_index(sync_dev, dst_bidx, dst_cidx);
-
- edma_set_transfer_params(sync_dev, acnt, bcnt, ccnt, 8, ABSYNC);
-
- edma_read_slot(sync_dev, template);
-
- /* don't bother with irqs or chaining */
- template->opt |= EDMA_CHAN_SLOT(sync_dev) << 12;
+ dmaengine_terminate_all(sync_dev);
}
-static void mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
+static int mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
struct mmc_data *data)
{
- struct edmacc_param *template;
- int channel, slot;
- unsigned link;
- struct scatterlist *sg;
- unsigned sg_len;
- unsigned bytes_left = host->bytes_left;
- const unsigned shift = ffs(rw_threshold) - 1;
+ struct dma_chan *chan;
+ struct dma_async_tx_descriptor *desc;
+ int ret = 0;
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
- template = &host->tx_template;
- channel = host->txdma;
+ struct dma_slave_config dma_tx_conf = {
+ .direction = DMA_MEM_TO_DEV,
+ .dst_addr = host->mem_res->start + DAVINCI_MMCDXR,
+ .dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+ .dst_maxburst =
+ rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
+ };
+ chan = host->dma_tx;
+ dmaengine_slave_config(host->dma_tx, &dma_tx_conf);
+
+ desc = dmaengine_prep_slave_sg(host->dma_tx,
+ data->sg,
+ host->sg_len,
+ DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc) {
+ dev_dbg(mmc_dev(host->mmc),
+ "failed to allocate DMA TX descriptor");
+ ret = -1;
+ goto out;
+ }
} else {
- template = &host->rx_template;
- channel = host->rxdma;
- }
-
- /* We know sg_len and ccnt will never be out of range because
- * we told the mmc layer which in turn tells the block layer
- * to ensure that it only hands us one scatterlist segment
- * per EDMA PARAM entry. Update the PARAM
- * entries needed for each segment of this scatterlist.
- */
- for (slot = channel, link = 0, sg = data->sg, sg_len = host->sg_len;
- sg_len-- != 0 && bytes_left;
- sg = sg_next(sg), slot = host->links[link++]) {
- u32 buf = sg_dma_address(sg);
- unsigned count = sg_dma_len(sg);
-
- template->link_bcntrld = sg_len
- ? (EDMA_CHAN_SLOT(host->links[link]) << 5)
- : 0xffff;
-
- if (count > bytes_left)
- count = bytes_left;
- bytes_left -= count;
-
- if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE)
- template->src = buf;
- else
- template->dst = buf;
- template->ccnt = count >> shift;
-
- edma_write_slot(slot, template);
+ struct dma_slave_config dma_rx_conf = {
+ .direction = DMA_DEV_TO_MEM,
+ .src_addr = host->mem_res->start + DAVINCI_MMCDRR,
+ .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+ .src_maxburst =
+ rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
+ };
+ chan = host->dma_rx;
+ dmaengine_slave_config(host->dma_rx, &dma_rx_conf);
+
+ desc = dmaengine_prep_slave_sg(host->dma_rx,
+ data->sg,
+ host->sg_len,
+ DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc) {
+ dev_dbg(mmc_dev(host->mmc),
+ "failed to allocate DMA RX descriptor");
+ ret = -1;
+ goto out;
+ }
}
- if (host->version == MMC_CTLR_VERSION_2)
- edma_clear_event(channel);
+ dmaengine_submit(desc);
+ dma_async_issue_pending(chan);
- edma_start(channel);
+out:
+ return ret;
}
static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
@@ -564,6 +478,7 @@ static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
{
int i;
int mask = rw_threshold - 1;
+ int ret = 0;
host->sg_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
((data->flags & MMC_DATA_WRITE)
@@ -583,70 +498,48 @@ static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
}
host->do_dma = 1;
- mmc_davinci_send_dma_request(host, data);
+ ret = mmc_davinci_send_dma_request(host, data);
- return 0;
+ return ret;
}
static void __init_or_module
davinci_release_dma_channels(struct mmc_davinci_host *host)
{
- unsigned i;
-
if (!host->use_dma)
return;
- for (i = 0; i < host->n_link; i++)
- edma_free_slot(host->links[i]);
-
- edma_free_channel(host->txdma);
- edma_free_channel(host->rxdma);
+ dma_release_channel(host->dma_tx);
+ dma_release_channel(host->dma_rx);
}
static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host)
{
- u32 link_size;
- int r, i;
-
- /* Acquire master DMA write channel */
- r = edma_alloc_channel(host->txdma, mmc_davinci_dma_cb, host,
- EVENTQ_DEFAULT);
- if (r < 0) {
- dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
- "tx", r);
- return r;
- }
- mmc_davinci_dma_setup(host, true, &host->tx_template);
-
- /* Acquire master DMA read channel */
- r = edma_alloc_channel(host->rxdma, mmc_davinci_dma_cb, host,
- EVENTQ_DEFAULT);
- if (r < 0) {
- dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
- "rx", r);
- goto free_master_write;
+ int r;
+ dma_cap_mask_t mask;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ host->dma_tx =
+ dma_request_channel(mask, edma_filter_fn, &host->txdma);
+ if (!host->dma_tx) {
+ dev_err(mmc_dev(host->mmc), "Can't get dma_tx channel\n");
+ return -ENODEV;
}
- mmc_davinci_dma_setup(host, false, &host->rx_template);
- /* Allocate parameter RAM slots, which will later be bound to a
- * channel as needed to handle a scatterlist.
- */
- link_size = min_t(unsigned, host->nr_sg, ARRAY_SIZE(host->links));
- for (i = 0; i < link_size; i++) {
- r = edma_alloc_slot(EDMA_CTLR(host->txdma), EDMA_SLOT_ANY);
- if (r < 0) {
- dev_dbg(mmc_dev(host->mmc), "dma PaRAM alloc --> %d\n",
- r);
- break;
- }
- host->links[i] = r;
+ host->dma_rx =
+ dma_request_channel(mask, edma_filter_fn, &host->rxdma);
+ if (!host->dma_rx) {
+ dev_err(mmc_dev(host->mmc), "Can't get dma_rx channel\n");
+ r = -ENODEV;
+ goto free_master_write;
}
- host->n_link = i;
return 0;
free_master_write:
- edma_free_channel(host->txdma);
+ dma_release_channel(host->dma_tx);
return r;
}
@@ -1359,7 +1252,7 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
* Each hw_seg uses one EDMA parameter RAM slot, always one
* channel and then usually some linked slots.
*/
- mmc->max_segs = 1 + host->n_link;
+ mmc->max_segs = MAX_NR_SG;
/* EDMA limit per hw segment (one or two MBytes) */
mmc->max_seg_size = MAX_CCNT * rw_threshold;
--
1.7.9.5
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