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Merged
merged 2 commits into from
Mar 8, 2016
Merged

bcm2835-sdhost: Only claim one DMA channel #1329

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06c1699
bcm2835-sdhost: Only claim one DMA channel
Mar 7, 2016
af80d75
bcm2835-mmc: Only claim one DMA channel
Mar 8, 2016
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10 changes: 4 additions & 6 deletions arch/arm/boot/dts/bcm2708_common.dtsi
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -136,9 +136,8 @@
reg = <0x7e202000 0x100>;
interrupts = <2 24>;
clocks = <&clk_core>;
dmas = <&dma 13>,
<&dma 13>;
dma-names = "tx", "rx";
dmas = <&dma 13>;
dma-names = "rx-tx";
brcm,overclock-50 = <0>;
brcm,pio-limit = <1>;
status = "disabled";
Expand Down Expand Up @@ -233,9 +232,8 @@
reg = <0x7e300000 0x100>;
interrupts = <2 30>;
clocks = <&clk_mmc>;
dmas = <&dma 11>,
<&dma 11>;
dma-names = "tx", "rx";
dmas = <&dma 11>;
dma-names = "rx-tx";
brcm,overclock-50 = <0>;
status = "disabled";
};
Expand Down
69 changes: 49 additions & 20 deletions drivers/mmc/host/bcm2835-mmc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,8 +108,9 @@ struct bcm2835_host {
u32 shadow;

/*DMA part*/
struct dma_chan *dma_chan_rx; /* DMA channel for reads */
struct dma_chan *dma_chan_tx; /* DMA channel for writes */
struct dma_chan *dma_chan_rxtx; /* DMA channel for reads and writes */
struct dma_slave_config dma_cfg_rx;
struct dma_slave_config dma_cfg_tx;
struct dma_async_tx_descriptor *tx_desc; /* descriptor */

bool have_dma;
Expand Down Expand Up @@ -342,7 +343,7 @@ static void bcm2835_mmc_dma_complete(void *param)

if (host->data && !(host->data->flags & MMC_DATA_WRITE)) {
/* otherwise handled in SDHCI IRQ */
dma_chan = host->dma_chan_rx;
dma_chan = host->dma_chan_rxtx;
dir_data = DMA_FROM_DEVICE;

dma_unmap_sg(dma_chan->device->dev,
Expand Down Expand Up @@ -493,16 +494,21 @@ static void bcm2835_mmc_transfer_dma(struct bcm2835_host *host)
if (host->blocks == 0)
return;

dma_chan = host->dma_chan_rxtx;
if (host->data->flags & MMC_DATA_READ) {
dma_chan = host->dma_chan_rx;
dir_data = DMA_FROM_DEVICE;
dir_slave = DMA_DEV_TO_MEM;
} else {
dma_chan = host->dma_chan_tx;
dir_data = DMA_TO_DEVICE;
dir_slave = DMA_MEM_TO_DEV;
}

/* The parameters have already been validated, so this will not fail */
(void)dmaengine_slave_config(dma_chan,
(dir_data == DMA_FROM_DEVICE) ?
&host->dma_cfg_rx :
&host->dma_cfg_tx);

BUG_ON(!dma_chan->device);
BUG_ON(!dma_chan->device->dev);
BUG_ON(!host->data->sg);
Expand Down Expand Up @@ -936,7 +942,7 @@ static void bcm2835_mmc_data_irq(struct bcm2835_host *host, u32 intmask)
if (host->data->flags & MMC_DATA_WRITE) {
/* IRQ handled here */

dma_chan = host->dma_chan_tx;
dma_chan = host->dma_chan_rxtx;
dir_data = DMA_TO_DEVICE;
dma_unmap_sg(dma_chan->device->dev,
host->data->sg, host->data->sg_len,
Expand Down Expand Up @@ -1316,28 +1322,47 @@ static int bcm2835_mmc_add_host(struct bcm2835_host *host)
dev_info(dev, "Forcing PIO mode\n");
host->have_dma = false;
#else
if (IS_ERR_OR_NULL(host->dma_chan_tx) ||
IS_ERR_OR_NULL(host->dma_chan_rx)) {
dev_err(dev, "%s: Unable to initialise DMA channels. Falling back to PIO\n",
if (IS_ERR_OR_NULL(host->dma_chan_rxtx)) {
dev_err(dev, "%s: Unable to initialise DMA channel. Falling back to PIO\n",
DRIVER_NAME);
host->have_dma = false;
} else {
dev_info(dev, "DMA channels allocated");
host->have_dma = true;
dev_info(dev, "DMA channel allocated");

cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
cfg.slave_id = 11; /* DREQ channel */

/* Validate the slave configurations */

cfg.direction = DMA_MEM_TO_DEV;
cfg.src_addr = 0;
cfg.dst_addr = host->bus_addr + SDHCI_BUFFER;
ret = dmaengine_slave_config(host->dma_chan_tx, &cfg);

cfg.direction = DMA_DEV_TO_MEM;
cfg.src_addr = host->bus_addr + SDHCI_BUFFER;
cfg.dst_addr = 0;
ret = dmaengine_slave_config(host->dma_chan_rx, &cfg);
ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);

if (ret == 0) {
host->dma_cfg_tx = cfg;

cfg.direction = DMA_DEV_TO_MEM;
cfg.src_addr = host->bus_addr + SDHCI_BUFFER;
cfg.dst_addr = 0;

ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);
}

if (ret == 0) {
host->dma_cfg_rx = cfg;

host->use_dma = true;
} else {
pr_err("%s: unable to configure DMA channel. "
"Faling back to PIO\n",
mmc_hostname(mmc));
dma_release_channel(host->dma_chan_rxtx);
host->dma_chan_rxtx = NULL;
host->use_dma = false;
}
}
#endif
mmc->max_segs = 128;
Expand Down Expand Up @@ -1416,16 +1441,20 @@ static int bcm2835_mmc_probe(struct platform_device *pdev)

#ifndef FORCE_PIO
if (node) {
host->dma_chan_tx = dma_request_slave_channel(dev, "tx");
host->dma_chan_rx = dma_request_slave_channel(dev, "rx");
host->dma_chan_rxtx = dma_request_slave_channel(dev, "rx-tx");
if (!host->dma_chan_rxtx)
host->dma_chan_rxtx =
dma_request_slave_channel(dev, "tx");
if (!host->dma_chan_rxtx)
host->dma_chan_rxtx =
dma_request_slave_channel(dev, "rx");
} else {
dma_cap_mask_t mask;

dma_cap_zero(mask);
/* we don't care about the channel, any would work */
dma_cap_set(DMA_SLAVE, mask);
host->dma_chan_tx = dma_request_channel(mask, NULL, NULL);
host->dma_chan_rx = dma_request_channel(mask, NULL, NULL);
host->dma_chan_rxtx = dma_request_channel(mask, NULL, NULL);
}
#endif
clk = devm_clk_get(dev, NULL);
Expand Down
70 changes: 48 additions & 22 deletions drivers/mmc/host/bcm2835-sdhost.c
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -185,9 +185,10 @@ struct bcm2835_host {
unsigned int debug:1; /* Enable debug output */

/*DMA part*/
struct dma_chan *dma_chan_rx; /* DMA channel for reads */
struct dma_chan *dma_chan_tx; /* DMA channel for writes */
struct dma_chan *dma_chan; /* Channel in used */
struct dma_chan *dma_chan_rxtx; /* DMA channel for reads and writes */
struct dma_chan *dma_chan; /* Channel in use */
struct dma_slave_config dma_cfg_rx;
struct dma_slave_config dma_cfg_tx;
struct dma_async_tx_descriptor *dma_desc;
u32 dma_dir;
u32 drain_words;
Expand Down Expand Up @@ -771,12 +772,11 @@ static void bcm2835_sdhost_prepare_dma(struct bcm2835_host *host,
log_event("PRD<", (u32)data, 0);
pr_debug("bcm2835_sdhost_prepare_dma()\n");

dma_chan = host->dma_chan_rxtx;
if (data->flags & MMC_DATA_READ) {
dma_chan = host->dma_chan_rx;
dir_data = DMA_FROM_DEVICE;
dir_slave = DMA_DEV_TO_MEM;
} else {
dma_chan = host->dma_chan_tx;
dir_data = DMA_TO_DEVICE;
dir_slave = DMA_MEM_TO_DEV;
}
Expand Down Expand Up @@ -813,6 +813,12 @@ static void bcm2835_sdhost_prepare_dma(struct bcm2835_host *host,
host->drain_words = len/4;
}

/* The parameters have already been validated, so this will not fail */
(void)dmaengine_slave_config(dma_chan,
(dir_data == DMA_FROM_DEVICE) ?
&host->dma_cfg_rx :
&host->dma_cfg_tx);

len = dma_map_sg(dma_chan->device->dev, data->sg, data->sg_len,
dir_data);

Expand Down Expand Up @@ -1805,28 +1811,46 @@ int bcm2835_sdhost_add_host(struct bcm2835_host *host)
spin_lock_init(&host->lock);

if (host->allow_dma) {
if (IS_ERR_OR_NULL(host->dma_chan_tx) ||
IS_ERR_OR_NULL(host->dma_chan_rx)) {
pr_err("%s: unable to initialise DMA channels. "
if (IS_ERR_OR_NULL(host->dma_chan_rxtx)) {
pr_err("%s: unable to initialise DMA channel. "
"Falling back to PIO\n",
mmc_hostname(mmc));
host->use_dma = false;
} else {
host->use_dma = true;

cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
cfg.slave_id = 13; /* DREQ channel */

/* Validate the slave configurations */

cfg.direction = DMA_MEM_TO_DEV;
cfg.src_addr = 0;
cfg.dst_addr = host->bus_addr + SDDATA;
ret = dmaengine_slave_config(host->dma_chan_tx, &cfg);

cfg.direction = DMA_DEV_TO_MEM;
cfg.src_addr = host->bus_addr + SDDATA;
cfg.dst_addr = 0;
ret = dmaengine_slave_config(host->dma_chan_rx, &cfg);
ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);

if (ret == 0) {
host->dma_cfg_tx = cfg;

cfg.direction = DMA_DEV_TO_MEM;
cfg.src_addr = host->bus_addr + SDDATA;
cfg.dst_addr = 0;

ret = dmaengine_slave_config(host->dma_chan_rxtx, &cfg);
}

if (ret == 0) {
host->dma_cfg_rx = cfg;

host->use_dma = true;
} else {
pr_err("%s: unable to configure DMA channel. "
"Falling back to PIO\n",
mmc_hostname(mmc));
dma_release_channel(host->dma_chan_rxtx);
host->dma_chan_rxtx = NULL;
host->use_dma = false;
}
}
} else {
host->use_dma = false;
Expand Down Expand Up @@ -1948,19 +1972,21 @@ static int bcm2835_sdhost_probe(struct platform_device *pdev)

if (host->allow_dma) {
if (node) {
host->dma_chan_tx =
dma_request_slave_channel(dev, "tx");
host->dma_chan_rx =
dma_request_slave_channel(dev, "rx");
host->dma_chan_rxtx =
dma_request_slave_channel(dev, "rx-tx");
if (!host->dma_chan_rxtx)
host->dma_chan_rxtx =
dma_request_slave_channel(dev, "tx");
if (!host->dma_chan_rxtx)
host->dma_chan_rxtx =
dma_request_slave_channel(dev, "rx");
} else {
dma_cap_mask_t mask;

dma_cap_zero(mask);
/* we don't care about the channel, any would work */
dma_cap_set(DMA_SLAVE, mask);
host->dma_chan_tx =
dma_request_channel(mask, NULL, NULL);
host->dma_chan_rx =
host->dma_chan_rxtx =
dma_request_channel(mask, NULL, NULL);
}
}
Expand Down