On Wed, 2012-05-09 at 19:33 +0800, Richard Zhao wrote:
> device_prep_dma_cyclic may be call in audio trigger function which is
> atomic context, so we make it atomic too.
>
> - change channel0 lock to spinlock.
> - Use polling to wait for channel0 finish running.
>
> Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxxxxx>
Can you pls rebase this against the slave-dma next and resend.
It fails to apply for me.
> ---
> drivers/dma/imx-sdma.c | 57 ++++++++++++++++++++++++++---------------------
> 1 files changed, 31 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index fddccae..4fd48eb 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -24,7 +24,7 @@
> #include <linux/mm.h>
> #include <linux/interrupt.h>
> #include <linux/clk.h>
> -#include <linux/wait.h>
> +#include <linux/delay.h>
> #include <linux/sched.h>
> #include <linux/semaphore.h>
> #include <linux/spinlock.h>
> @@ -324,7 +324,7 @@ struct sdma_engine {
> struct dma_device dma_device;
> struct clk *clk_ipg;
> struct clk *clk_ahb;
> - struct mutex channel_0_lock;
> + spinlock_t channel_0_lock;
> struct sdma_script_start_addrs *script_addrs;
> };
>
> @@ -402,19 +402,27 @@ static void sdma_enable_channel(struct sdma_engine *sdma, int channel)
> }
>
> /*
> - * sdma_run_channel - run a channel and wait till it's done
> + * sdma_run_channel0 - run a channel and wait till it's done
> */
> -static int sdma_run_channel(struct sdma_channel *sdmac)
> +static int sdma_run_channel0(struct sdma_engine *sdma)
> {
> - struct sdma_engine *sdma = sdmac->sdma;
> - int channel = sdmac->channel;
> int ret;
> + unsigned long timeout = 500;
>
> - init_completion(&sdmac->done);
> + sdma_enable_channel(sdma, 0);
>
> - sdma_enable_channel(sdma, channel);
> + while (!(ret = readl_relaxed(sdma->regs + SDMA_H_INTR) & 1)) {
> + if (timeout-- <= 0)
> + break;
> + udelay(1);
> + }
>
> - ret = wait_for_completion_timeout(&sdmac->done, HZ);
> + if (ret) {
> + /* Clear the interrupt status */
> + writel_relaxed(ret, sdma->regs + SDMA_H_INTR);
> + } else {
> + dev_err(sdma->dev, "Timeout waiting for CH0 ready\n");
> + }
>
> return ret ? 0 : -ETIMEDOUT;
> }
> @@ -426,17 +434,17 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
> void *buf_virt;
> dma_addr_t buf_phys;
> int ret;
> -
> - mutex_lock(&sdma->channel_0_lock);
> + unsigned long flags;
>
> buf_virt = dma_alloc_coherent(NULL,
> size,
> &buf_phys, GFP_KERNEL);
> if (!buf_virt) {
> - ret = -ENOMEM;
> - goto err_out;
> + return -ENOMEM;
> }
>
> + spin_lock_irqsave(&sdma->channel_0_lock, flags);
> +
> bd0->mode.command = C0_SETPM;
> bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
> bd0->mode.count = size / 2;
> @@ -445,12 +453,11 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
>
> memcpy(buf_virt, buf, size);
>
> - ret = sdma_run_channel(&sdma->channel[0]);
> + ret = sdma_run_channel0(sdma);
>
> - dma_free_coherent(NULL, size, buf_virt, buf_phys);
> + spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
>
> -err_out:
> - mutex_unlock(&sdma->channel_0_lock);
> + dma_free_coherent(NULL, size, buf_virt, buf_phys);
>
> return ret;
> }
> @@ -539,10 +546,6 @@ static void mxc_sdma_handle_channel(struct sdma_channel *sdmac)
> {
> complete(&sdmac->done);
>
> - /* not interested in channel 0 interrupts */
> - if (sdmac->channel == 0)
> - return;
> -
> if (sdmac->flags & IMX_DMA_SG_LOOP)
> sdma_handle_channel_loop(sdmac);
> else
> @@ -555,6 +558,8 @@ static irqreturn_t sdma_int_handler(int irq, void *dev_id)
> unsigned long stat;
>
> stat = readl_relaxed(sdma->regs + SDMA_H_INTR);
> + /* not interested in channel 0 interrupts */
> + stat &= ~1;
> writel_relaxed(stat, sdma->regs + SDMA_H_INTR);
>
> while (stat) {
> @@ -660,6 +665,7 @@ static int sdma_load_context(struct sdma_channel *sdmac)
> struct sdma_context_data *context = sdma->context;
> struct sdma_buffer_descriptor *bd0 = sdma->channel[0].bd;
> int ret;
> + unsigned long flags;
>
> if (sdmac->direction == DMA_DEV_TO_MEM) {
> load_address = sdmac->pc_from_device;
> @@ -677,7 +683,7 @@ static int sdma_load_context(struct sdma_channel *sdmac)
> dev_dbg(sdma->dev, "event_mask0 = 0x%08x\n", (u32)sdmac->event_mask[0]);
> dev_dbg(sdma->dev, "event_mask1 = 0x%08x\n", (u32)sdmac->event_mask[1]);
>
> - mutex_lock(&sdma->channel_0_lock);
> + spin_lock_irqsave(&sdma->channel_0_lock, flags);
>
> memset(context, 0, sizeof(*context));
> context->channel_state.pc = load_address;
> @@ -696,10 +702,9 @@ static int sdma_load_context(struct sdma_channel *sdmac)
> bd0->mode.count = sizeof(*context) / 4;
> bd0->buffer_addr = sdma->context_phys;
> bd0->ext_buffer_addr = 2048 + (sizeof(*context) / 4) * channel;
> + ret = sdma_run_channel0(sdma);
>
> - ret = sdma_run_channel(&sdma->channel[0]);
> -
> - mutex_unlock(&sdma->channel_0_lock);
> + spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
>
> return ret;
> }
> @@ -1305,7 +1310,7 @@ static int __init sdma_probe(struct platform_device *pdev)
> if (!sdma)
> return -ENOMEM;
>
> - mutex_init(&sdma->channel_0_lock);
> + spin_lock_init(&sdma->channel_0_lock);
>
> sdma->dev = &pdev->dev;
>
--
~Vinod
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