From: Huang Shijie shijie8@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@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);