omap_hsmmc: avoid requesting dma repeatedly

omap_request_dma() is rather expensive operation, so don't release the
channel after every transfer, release only on autosuspend instead.

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index ef175c1..348f577 100644 (file)
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -175,6 +175,7 @@ struct omap_hsmmc_host {
        int                     suspended;
        int                     irq;
        int                     use_dma, dma_ch;
        int                     suspended;
        int                     irq;
        int                     use_dma, dma_ch;

+       int                     dma_ch_tx, dma_ch_rx;

        int                     dma_line_tx, dma_line_rx;
        int                     slot_id;
        int                     got_dbclk;
        int                     dma_line_tx, dma_line_rx;
        int                     slot_id;
        int                     got_dbclk;


@@ -1056,7 +1057,6 @@ static void omap_hsmmc_dma_cleanup(struct omap_hsmmc_host *host, int errno)
                dma_unmap_sg(mmc_dev(host->mmc), host->data->sg,
                        host->data->sg_len,
                        omap_hsmmc_get_dma_dir(host, host->data));
                dma_unmap_sg(mmc_dev(host->mmc), host->data->sg,
                        host->data->sg_len,
                        omap_hsmmc_get_dma_dir(host, host->data));

-               omap_free_dma(dma_ch);

                host->data->host_cookie = 0;
        }
        host->data = NULL;
                host->data->host_cookie = 0;
        }
        host->data = NULL;


@@ -1414,7 +1414,7 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
 {
        struct omap_hsmmc_host *host = cb_data;
        struct mmc_data *data;
 {
        struct omap_hsmmc_host *host = cb_data;
        struct mmc_data *data;

-       int dma_ch, req_in_progress;
+       int req_in_progress;

 
        if (!(ch_status & OMAP_DMA_BLOCK_IRQ)) {
                dev_warn(mmc_dev(host->mmc), "unexpected dma status %x\n",
 
        if (!(ch_status & OMAP_DMA_BLOCK_IRQ)) {
                dev_warn(mmc_dev(host->mmc), "unexpected dma status %x\n",


@@ -1443,12 +1443,9 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
                             omap_hsmmc_get_dma_dir(host, data));
 
        req_in_progress = host->req_in_progress;
                             omap_hsmmc_get_dma_dir(host, data));
 
        req_in_progress = host->req_in_progress;

-       dma_ch = host->dma_ch;

        host->dma_ch = -1;
        spin_unlock(&host->irq_lock);
 
        host->dma_ch = -1;
        spin_unlock(&host->irq_lock);
 

-       omap_free_dma(dma_ch);
-

        /* If DMA has finished after TC, complete the request */
        if (!req_in_progress) {
                struct mmc_request *mrq = host->mrq;
        /* If DMA has finished after TC, complete the request */
        if (!req_in_progress) {
                struct mmc_request *mrq = host->mrq;


@@ -1522,14 +1519,29 @@ static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
 
        BUG_ON(host->dma_ch != -1);
 
 
        BUG_ON(host->dma_ch != -1);
 

-       ret = omap_request_dma(omap_hsmmc_get_dma_sync_dev(host, data),
-                              "MMC/SD", omap_hsmmc_dma_cb, host, &dma_ch);
-       if (unlikely(ret != 0)) {
-               dev_err(mmc_dev(host->mmc),
-                       "%s: omap_request_dma() failed with %d\n",
-                       mmc_hostname(host->mmc), ret);
-               return ret;
+       if (data->flags & MMC_DATA_WRITE)
+               dma_ch = host->dma_ch_tx;
+       else
+               dma_ch = host->dma_ch_rx;
+
+       if (dma_ch == -1) {
+               ret = omap_request_dma(omap_hsmmc_get_dma_sync_dev(host, data),
+                                      "MMC/SD", omap_hsmmc_dma_cb, host, &dma_ch);
+               if (unlikely(ret != 0)) {
+                       dev_err(mmc_dev(host->mmc),
+                               "%s: omap_request_dma() failed with %d\n",
+                               mmc_hostname(host->mmc), ret);
+                       return ret;
+               }
+
+               omap_hsmmc_config_dma_params_once(host, data, dma_ch);
+
+               if (data->flags & MMC_DATA_WRITE)
+                       host->dma_ch_tx = dma_ch;
+               else
+                       host->dma_ch_rx = dma_ch;

        }
        }

+

        ret = omap_hsmmc_pre_dma_transfer(host, data, NULL);
        if (unlikely(ret))
                return ret;
        ret = omap_hsmmc_pre_dma_transfer(host, data, NULL);
        if (unlikely(ret))
                return ret;


@@ -1537,7 +1549,6 @@ static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
        host->dma_ch = dma_ch;
        host->dma_sg_idx = 0;
 
        host->dma_ch = dma_ch;
        host->dma_sg_idx = 0;
 

-       omap_hsmmc_config_dma_params_once(host, data, dma_ch);

        omap_hsmmc_config_dma_params(host, data, data->sg);
 
        return 0;
        omap_hsmmc_config_dma_params(host, data, data->sg);
 
        return 0;


@@ -1989,6 +2000,8 @@ static int __init omap_hsmmc_probe(struct platform_device *pdev)
        host->use_dma   = 1;
        host->dev->dma_mask = &pdata->dma_mask;
        host->dma_ch    = -1;
        host->use_dma   = 1;
        host->dev->dma_mask = &pdata->dma_mask;
        host->dma_ch    = -1;

+       host->dma_ch_tx = -1;
+       host->dma_ch_rx = -1;

        host->irq       = irq;
        host->id        = pdev->id;
        host->slot_id   = 0;
        host->irq       = irq;
        host->id        = pdev->id;
        host->slot_id   = 0;


@@ -2333,9 +2346,19 @@ static int omap_hsmmc_resume(struct device *dev)
 static int omap_hsmmc_runtime_suspend(struct device *dev)
 {
        struct omap_hsmmc_host *host;
 static int omap_hsmmc_runtime_suspend(struct device *dev)
 {
        struct omap_hsmmc_host *host;

+       int dma_ch;

 
        host = platform_get_drvdata(to_platform_device(dev));
        omap_hsmmc_context_save(host);
 
        host = platform_get_drvdata(to_platform_device(dev));
        omap_hsmmc_context_save(host);

+
+       dma_ch = xchg(&host->dma_ch_tx, -1);
+       if (dma_ch != -1)
+               omap_free_dma(dma_ch);
+
+       dma_ch = xchg(&host->dma_ch_rx, -1);
+       if (dma_ch != -1)
+               omap_free_dma(dma_ch);
+

        dev_dbg(mmc_dev(host->mmc), "disabled\n");
 
        return 0;
        dev_dbg(mmc_dev(host->mmc), "disabled\n");
 
        return 0;