Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[cascardo/linux.git] / drivers / dma / imx-sdma.c

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 0f6fd42..3cb4738 100644 (file)
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/init.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/bitops.h>
@@ -385,6 +386,7 @@ struct sdma_engine {
        const struct sdma_driver_data   *drvdata;
        u32                             spba_start_addr;
        u32                             spba_end_addr;
+       unsigned int                    irq;
 };
 
 static struct sdma_driver_data sdma_imx31 = {
@@ -571,28 +573,20 @@ static void sdma_enable_channel(struct sdma_engine *sdma, int channel)
 static int sdma_run_channel0(struct sdma_engine *sdma)
 {
        int ret;
-       unsigned long timeout = 500;
+       u32 reg;
 
        sdma_enable_channel(sdma, 0);
 
-       while (!(ret = readl_relaxed(sdma->regs + SDMA_H_INTR) & 1)) {
-               if (timeout-- <= 0)
-                       break;
-               udelay(1);
-       }
-
-       if (ret) {
-               /* Clear the interrupt status */
-               writel_relaxed(ret, sdma->regs + SDMA_H_INTR);
-       } else {
+       ret = readl_relaxed_poll_timeout_atomic(sdma->regs + SDMA_H_STATSTOP,
+                                               reg, !(reg & 1), 1, 500);
+       if (ret)
                dev_err(sdma->dev, "Timeout waiting for CH0 ready\n");
-       }
 
        /* Set bits of CONFIG register with dynamic context switching */
        if (readl(sdma->regs + SDMA_H_CONFIG) == 0)
                writel_relaxed(SDMA_H_CONFIG_CSM, sdma->regs + SDMA_H_CONFIG);
 
-       return ret ? 0 : -ETIMEDOUT;
+       return ret;
 }
 
 static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
@@ -654,15 +648,11 @@ static void sdma_event_disable(struct sdma_channel *sdmac, unsigned int event)
        writel_relaxed(val, sdma->regs + chnenbl);
 }
 
-static void sdma_handle_channel_loop(struct sdma_channel *sdmac)
-{
-       if (sdmac->desc.callback)
-               sdmac->desc.callback(sdmac->desc.callback_param);
-}
-
 static void sdma_update_channel_loop(struct sdma_channel *sdmac)
 {
        struct sdma_buffer_descriptor *bd;
+       int error = 0;
+       enum dma_status old_status = sdmac->status;
 
        /*
         * loop mode. Iterate over descriptors, re-setup them and
@@ -674,17 +664,42 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac)
                if (bd->mode.status & BD_DONE)
                        break;
 
-               if (bd->mode.status & BD_RROR)
+               if (bd->mode.status & BD_RROR) {
+                       bd->mode.status &= ~BD_RROR;
                        sdmac->status = DMA_ERROR;
+                       error = -EIO;
+               }
+
+              /*
+               * We use bd->mode.count to calculate the residue, since contains
+               * the number of bytes present in the current buffer descriptor.
+               */
 
+               sdmac->chn_real_count = bd->mode.count;
                bd->mode.status |= BD_DONE;
+               bd->mode.count = sdmac->period_len;
+
+               /*
+                * The callback is called from the interrupt context in order
+                * to reduce latency and to avoid the risk of altering the
+                * SDMA transaction status by the time the client tasklet is
+                * executed.
+                */
+
+               if (sdmac->desc.callback)
+                       sdmac->desc.callback(sdmac->desc.callback_param);
+
                sdmac->buf_tail++;
                sdmac->buf_tail %= sdmac->num_bd;
+
+               if (error)
+                       sdmac->status = old_status;
        }
 }
 
-static void mxc_sdma_handle_channel_normal(struct sdma_channel *sdmac)
+static void mxc_sdma_handle_channel_normal(unsigned long data)
 {
+       struct sdma_channel *sdmac = (struct sdma_channel *) data;
        struct sdma_buffer_descriptor *bd;
        int i, error = 0;
 
@@ -711,25 +726,15 @@ static void mxc_sdma_handle_channel_normal(struct sdma_channel *sdmac)
                sdmac->desc.callback(sdmac->desc.callback_param);
 }
 
-static void sdma_tasklet(unsigned long data)
-{
-       struct sdma_channel *sdmac = (struct sdma_channel *) data;
-
-       if (sdmac->flags & IMX_DMA_SG_LOOP)
-               sdma_handle_channel_loop(sdmac);
-       else
-               mxc_sdma_handle_channel_normal(sdmac);
-}
-
 static irqreturn_t sdma_int_handler(int irq, void *dev_id)
 {
        struct sdma_engine *sdma = 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);
+       /* channel 0 is special and not handled here, see run_channel0() */
+       stat &= ~1;
 
        while (stat) {
                int channel = fls(stat) - 1;
@@ -737,8 +742,8 @@ static irqreturn_t sdma_int_handler(int irq, void *dev_id)
 
                if (sdmac->flags & IMX_DMA_SG_LOOP)
                        sdma_update_channel_loop(sdmac);
-
-               tasklet_schedule(&sdmac->tasklet);
+               else
+                       tasklet_schedule(&sdmac->tasklet);
 
                __clear_bit(channel, &stat);
        }
@@ -758,7 +763,7 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
         * These are needed once we start to support transfers between
         * two peripherals or memory-to-memory transfers
         */
-       int per_2_per = 0, emi_2_emi = 0;
+       int per_2_per = 0;
 
        sdmac->pc_from_device = 0;
        sdmac->pc_to_device = 0;
@@ -766,7 +771,6 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
 
        switch (peripheral_type) {
        case IMX_DMATYPE_MEMORY:
-               emi_2_emi = sdma->script_addrs->ap_2_ap_addr;
                break;
        case IMX_DMATYPE_DSP:
                emi_2_per = sdma->script_addrs->bp_2_ap_addr;
@@ -999,8 +1003,6 @@ static int sdma_config_channel(struct dma_chan *chan)
                } else
                        __set_bit(sdmac->event_id0, sdmac->event_mask);
 
-               /* Watermark Level */
-               sdmac->watermark_level |= sdmac->watermark_level;
                /* Address */
                sdmac->shp_addr = sdmac->per_address;
                sdmac->per_addr = sdmac->per_address2;
@@ -1362,7 +1364,8 @@ static enum dma_status sdma_tx_status(struct dma_chan *chan,
        u32 residue;
 
        if (sdmac->flags & IMX_DMA_SG_LOOP)
-               residue = (sdmac->num_bd - sdmac->buf_tail) * sdmac->period_len;
+               residue = (sdmac->num_bd - sdmac->buf_tail) *
+                          sdmac->period_len - sdmac->chn_real_count;
        else
                residue = sdmac->chn_count - sdmac->chn_real_count;
 
@@ -1715,6 +1718,8 @@ static int sdma_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
+       sdma->irq = irq;
+
        sdma->script_addrs = kzalloc(sizeof(*sdma->script_addrs), GFP_KERNEL);
        if (!sdma->script_addrs)
                return -ENOMEM;
@@ -1739,7 +1744,7 @@ static int sdma_probe(struct platform_device *pdev)
                dma_cookie_init(&sdmac->chan);
                sdmac->channel = i;
 
-               tasklet_init(&sdmac->tasklet, sdma_tasklet,
+               tasklet_init(&sdmac->tasklet, mxc_sdma_handle_channel_normal,
                             (unsigned long) sdmac);
                /*
                 * Add the channel to the DMAC list. Do not add channel 0 though
@@ -1840,6 +1845,7 @@ static int sdma_remove(struct platform_device *pdev)
        struct sdma_engine *sdma = platform_get_drvdata(pdev);
        int i;
 
+       devm_free_irq(&pdev->dev, sdma->irq, sdma);
        dma_async_device_unregister(&sdma->dma_device);
        kfree(sdma->script_addrs);
        /* Kill the tasklet */