From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Zhao Subject: [PATCH Rebase 1/1] dma: imx-sdma: make channel0 operations atomic Date: Fri, 11 May 2012 15:14:27 +0800 Message-ID: <1336720467-29770-1-git-send-email-richard.zhao@freescale.com> References: <1336717928.15424.1597.camel@vkoul-udesk3> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1336717928.15424.1597.camel@vkoul-udesk3> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org Cc: shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, lrg-l0cyMroinI0@public.gmane.org, broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org, vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, dong.aisheng-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, timur-KZfg59tc24xl57MIdRCFDg@public.gmane.org, Richard Zhao List-Id: alsa-devel@alsa-project.org 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 --- 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 d3e38e2..79aa749 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -24,7 +24,7 @@ #include #include #include -#include +#include #include #include #include @@ -323,7 +323,7 @@ struct sdma_engine { dma_addr_t context_phys; struct dma_device dma_device; struct clk *clk; - struct mutex channel_0_lock; + spinlock_t channel_0_lock; struct sdma_script_start_addrs *script_addrs; }; @@ -401,19 +401,27 @@ 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; } @@ -425,17 +433,17 @@ 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; @@ -444,12 +452,11 @@ 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; } @@ -538,10 +545,6 @@ 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 @@ -554,6 +557,8 @@ 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) { @@ -659,6 +664,7 @@ 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; @@ -676,7 +682,7 @@ 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; @@ -695,10 +701,9 @@ 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; } @@ -1297,7 +1302,7 @@ 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; -- 1.7.5.4