[PATCH] dma: add new DMA control commands
Huang Shijie
b32955 at freescale.com
Thu Oct 18 01:32:15 EDT 2012
From: Huang Shijie <shijie8 at gmail.com>
[1] Why add these new DMA control commands?
In mx6q, the gpmi-nand driver is the only user of the APBH-DMA. The dma clock
is enabled when we have successfully requested a DMA channel. So even when
the gpmi-nand driver does not work, the dma clock(apbh-dma) still runs
in high speed (198MHz). To save some power, it is better to disable the dma
clock when the dma device, such as gpmi-nand, is not working anymore.
When the dma device becomes work again, enable the dma clock again.
[2] add new DMA control commands: DMA_START/DMA_END
DMA_START: do some preprations to start the DMA engine, such as enable the
necessary clocks.
DMA_END: do some works to end the DMA engine, such as disable the
necessary clocks.
[3] This patch does not change any logic in i2c-mxs driver and mxs-pcm driver.
But for gpmi-nand driver, we will enable the the clock only when we select
the nand chip, and want to do some real jobs with the nand chip.
For mxs-mmc driver, disable the dma clock in the suspend; and enable the
dma clock in the resume.
Signed-off-by: Huang Shijie <b32955 at freescale.com>
---
drivers/dma/mxs-dma.c | 17 +++++++++++++++++
drivers/i2c/busses/i2c-mxs.c | 10 +++++++++-
drivers/mmc/host/mxs-mmc.c | 19 ++++++++++++++++---
drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 10 ++++++++++
drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 10 ++++++----
include/linux/dmaengine.h | 6 ++++++
sound/soc/mxs/mxs-pcm.c | 12 ++++++++++++
7 files changed, 76 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index 9f02e79..89286f4 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -384,6 +384,8 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
/* the descriptor is ready */
async_tx_ack(&mxs_chan->desc);
+ clk_disable_unprepare(mxs_dma->clk);
+
return 0;
err_clk:
@@ -399,6 +401,14 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
{
struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
+ int ret;
+
+ ret = clk_prepare_enable(mxs_dma->clk);
+ if (ret) {
+ dev_err(mxs_dma->dma_device.dev,
+ "failed in enabling the dma clock\n");
+ return;
+ }
mxs_dma_disable_chan(mxs_chan);
@@ -597,9 +607,13 @@ static int mxs_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg)
{
struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
+ struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
int ret = 0;
switch (cmd) {
+ case DMA_START:
+ ret = clk_prepare_enable(mxs_dma->clk);
+ break;
case DMA_TERMINATE_ALL:
mxs_dma_reset_chan(mxs_chan);
mxs_dma_disable_chan(mxs_chan);
@@ -610,6 +624,9 @@ static int mxs_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
case DMA_RESUME:
mxs_dma_resume_chan(mxs_chan);
break;
+ case DMA_END:
+ clk_disable_unprepare(mxs_dma->clk);
+ break;
default:
ret = -ENOSYS;
}
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 1f58197..da1e881 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -643,6 +643,12 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
dev_err(dev, "Failed to request dma\n");
return -ENODEV;
}
+ err = dmaengine_device_control(i2c->dmach, DMA_START, 0);
+ if (err) {
+ dma_release_channel(i2c->dmach);
+ dev_err(dev, "Failed to start dma\n");
+ return err;
+ }
}
platform_set_drvdata(pdev, i2c);
@@ -680,8 +686,10 @@ static int __devexit mxs_i2c_remove(struct platform_device *pdev)
if (ret)
return -EBUSY;
- if (i2c->dmach)
+ if (i2c->dmach) {
+ dmaengine_device_control(i2c->dmach, DMA_END, 0);
dma_release_channel(i2c->dmach);
+ }
writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index 80d1e6d..aa91830 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -676,6 +676,9 @@ static int mxs_mmc_probe(struct platform_device *pdev)
"%s: failed to request dma\n", __func__);
goto out_clk_put;
}
+ ret = dmaengine_device_control(ssp->dmach, DMA_START, 0);
+ if (ret)
+ goto out_free_dma;
/* set mmc core parameters */
mmc->ops = &mxs_mmc_ops;
@@ -717,18 +720,20 @@ static int mxs_mmc_probe(struct platform_device *pdev)
ret = devm_request_irq(&pdev->dev, irq_err, mxs_mmc_irq_handler, 0,
DRIVER_NAME, host);
if (ret)
- goto out_free_dma;
+ goto out_end_free_dma;
spin_lock_init(&host->lock);
ret = mmc_add_host(mmc);
if (ret)
- goto out_free_dma;
+ goto out_end_free_dma;
dev_info(mmc_dev(host->mmc), "initialized\n");
return 0;
+out_end_free_dma:
+ dmaengine_device_control(ssp->dmach, DMA_END, 0);
out_free_dma:
if (ssp->dmach)
dma_release_channel(ssp->dmach);
@@ -750,8 +755,10 @@ static int mxs_mmc_remove(struct platform_device *pdev)
platform_set_drvdata(pdev, NULL);
- if (ssp->dmach)
+ if (ssp->dmach) {
+ dmaengine_device_control(ssp->dmach, DMA_END, 0);
dma_release_channel(ssp->dmach);
+ }
clk_disable_unprepare(ssp->clk);
clk_put(ssp->clk);
@@ -772,6 +779,7 @@ static int mxs_mmc_suspend(struct device *dev)
ret = mmc_suspend_host(mmc);
clk_disable_unprepare(ssp->clk);
+ dmaengine_device_control(ssp->dmach, DMA_END, 0);
return ret;
}
@@ -784,8 +792,13 @@ static int mxs_mmc_resume(struct device *dev)
int ret = 0;
clk_prepare_enable(ssp->clk);
+ ret = dmaengine_device_control(ssp->dmach, DMA_START, 0);
+ if (ret)
+ return ret;
ret = mmc_resume_host(mmc);
+ if (ret)
+ dmaengine_device_control(ssp->dmach, DMA_END, 0);
return ret;
}
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index 3502acc..20ed3f3 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -958,6 +958,7 @@ void gpmi_begin(struct gpmi_nand_data *this)
uint32_t reg;
unsigned int dll_wait_time_in_us;
struct gpmi_nfc_hardware_timing hw;
+ struct dma_chan *channel = get_dma_chan(this);
int ret;
/* Enable the clock. */
@@ -967,6 +968,12 @@ void gpmi_begin(struct gpmi_nand_data *this)
goto err_out;
}
+ ret = dmaengine_device_control(channel, DMA_START, 0);
+ if (ret) {
+ gpmi_disable_clk(this);
+ goto err_out;
+ }
+
/* Only initialize the timing once */
if (this->flags & GPMI_TIMING_INIT_OK)
return;
@@ -1035,7 +1042,10 @@ err_out:
void gpmi_end(struct gpmi_nand_data *this)
{
+ struct dma_chan *channel = get_dma_chan(this);
+
gpmi_disable_clk(this);
+ dmaengine_device_control(channel, DMA_END, 0);
}
/* Clears a BCH interrupt. */
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
index e2c56fc..5694d03 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
@@ -815,12 +815,14 @@ static void gpmi_select_chip(struct mtd_info *mtd, int chipnr)
struct nand_chip *chip = mtd->priv;
struct gpmi_nand_data *this = chip->priv;
- if ((this->current_chip < 0) && (chipnr >= 0))
+ if ((this->current_chip < 0) && (chipnr >= 0)) {
+ /* set the current_chip before we call gpmi_begin(). */
+ this->current_chip = chipnr;
gpmi_begin(this);
- else if ((this->current_chip >= 0) && (chipnr < 0))
+ } else if ((this->current_chip >= 0) && (chipnr < 0)) {
gpmi_end(this);
-
- this->current_chip = chipnr;
+ this->current_chip = chipnr;
+ }
}
static void gpmi_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index d3201e4..79f864a 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -199,6 +199,8 @@ enum dma_ctrl_flags {
/**
* enum dma_ctrl_cmd - DMA operations that can optionally be exercised
* on a running channel.
+ * @DMA_START: do some preprations to start the DMA engine, such as enable the
+ * necessary clocks.
* @DMA_TERMINATE_ALL: terminate all ongoing transfers
* @DMA_PAUSE: pause ongoing transfers
* @DMA_RESUME: resume paused transfer
@@ -209,13 +211,17 @@ enum dma_ctrl_flags {
* command.
* @FSLDMA_EXTERNAL_START: this command will put the Freescale DMA controller
* into external start mode.
+ * @DMA_END: do some works to end the DMA engine, such as disable the
+ * necessary clocks.
*/
enum dma_ctrl_cmd {
+ DMA_START,
DMA_TERMINATE_ALL,
DMA_PAUSE,
DMA_RESUME,
DMA_SLAVE_CONFIG,
FSLDMA_EXTERNAL_START,
+ DMA_END,
};
/**
diff --git a/sound/soc/mxs/mxs-pcm.c b/sound/soc/mxs/mxs-pcm.c
index f82d766..cfcc30f 100644
--- a/sound/soc/mxs/mxs-pcm.c
+++ b/sound/soc/mxs/mxs-pcm.c
@@ -92,6 +92,7 @@ static int snd_mxs_open(struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct mxs_pcm_dma_data *pcm_dma_data;
+ struct dma_chan *chan;
int ret;
pcm_dma_data = kzalloc(sizeof(*pcm_dma_data), GFP_KERNEL);
@@ -107,6 +108,14 @@ static int snd_mxs_open(struct snd_pcm_substream *substream)
return ret;
}
+ chan = snd_dmaengine_pcm_get_chan(substream);
+ ret = dmaengine_device_control(chan, DMA_START, (unsigned long)0);
+ if (ret) {
+ snd_dmaengine_pcm_close(substream);
+ kfree(pcm_dma_data);
+ return ret;
+ }
+
snd_soc_set_runtime_hwparams(substream, &snd_mxs_hardware);
snd_dmaengine_pcm_set_data(substream, pcm_dma_data);
@@ -117,7 +126,10 @@ static int snd_mxs_open(struct snd_pcm_substream *substream)
static int snd_mxs_close(struct snd_pcm_substream *substream)
{
struct mxs_pcm_dma_data *pcm_dma_data = snd_dmaengine_pcm_get_data(substream);
+ struct dma_chan *chan;
+ chan = snd_dmaengine_pcm_get_chan(substream);
+ dmaengine_device_control(chan, DMA_END, 0);
snd_dmaengine_pcm_close(substream);
kfree(pcm_dma_data);
--
1.7.0.4
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