mmc: mmci: implement pre_req() and post_req()

pre_req() runs dma_map_sg() and prepares the dma descriptor for the next
mmc data transfer. post_req() runs dma_unmap_sg.  If not calling pre_req()
before mmci_request(), mmci_request() will prepare the cache and dma just
like it did it before.  It is optional to use pre_req() and post_req()
for mmci.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 142 insertions, 13 deletions

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index fe140724a02e..fef7140eb1d0 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -226,6 +226,9 @@ static void __devinit mmci_dma_setup(struct mmci_host *host)
                 return;
         }
 
+        /* initialize pre request cookie */
+        host->next_data.cookie = 1;
+
         /* Try to acquire a generic DMA engine slave channel */
         dma_cap_zero(mask);
         dma_cap_set(DMA_SLAVE, mask);
@@ -335,7 +338,8 @@ static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
                 dir = DMA_FROM_DEVICE;
         }
 
-        dma_unmap_sg(chan->device->dev, data->sg, data->sg_len, dir);
+        if (!data->host_cookie)
+                dma_unmap_sg(chan->device->dev, data->sg, data->sg_len, dir);
 
         /*
          * Use of DMA with scatter-gather is impossible.
@@ -353,7 +357,8 @@ static void mmci_dma_data_error(struct mmci_host *host)
         dmaengine_terminate_all(host->dma_current);
 }
 
-static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
+static int mmci_dma_prep_data(struct mmci_host *host, struct mmc_data *data,
+                              struct mmci_host_next *next)
 {
         struct variant_data *variant = host->variant;
         struct dma_slave_config conf = {
@@ -364,13 +369,20 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
                 .src_maxburst = variant->fifohalfsize >> 2, /* # of words */
                 .dst_maxburst = variant->fifohalfsize >> 2, /* # of words */
         };
-        struct mmc_data *data = host->data;
         struct dma_chan *chan;
         struct dma_device *device;
         struct dma_async_tx_descriptor *desc;
         int nr_sg;
 
-        host->dma_current = NULL;
+        /* Check if next job is already prepared */
+        if (data->host_cookie && !next &&
+            host->dma_current && host->dma_desc_current)
+                return 0;
+
+        if (!next) {
+                host->dma_current = NULL;
+                host->dma_desc_current = NULL;
+        }
 
         if (data->flags & MMC_DATA_READ) {
                 conf.direction = DMA_FROM_DEVICE;
@@ -385,7 +397,7 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
                 return -EINVAL;
 
         /* If less than or equal to the fifo size, don't bother with DMA */
-        if (host->size <= variant->fifosize)
+        if (data->blksz * data->blocks <= variant->fifosize)
                 return -EINVAL;
 
         device = chan->device;
@@ -399,14 +411,38 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
         if (!desc)
                 goto unmap_exit;
 
-        /* Okay, go for it. */
-        host->dma_current = chan;
+        if (next) {
+                next->dma_chan = chan;
+                next->dma_desc = desc;
+        } else {
+                host->dma_current = chan;
+                host->dma_desc_current = desc;
+        }
+
+        return 0;
 
+ unmap_exit:
+        if (!next)
+                dmaengine_terminate_all(chan);
+        dma_unmap_sg(device->dev, data->sg, data->sg_len, conf.direction);
+        return -ENOMEM;
+}
+
+static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
+{
+        int ret;
+        struct mmc_data *data = host->data;
+
+        ret = mmci_dma_prep_data(host, host->data, NULL);
+        if (ret)
+                return ret;
+
+        /* Okay, go for it. */
         dev_vdbg(mmc_dev(host->mmc),
                  "Submit MMCI DMA job, sglen %d blksz %04x blks %04x flags %08x\n",
                  data->sg_len, data->blksz, data->blocks, data->flags);
-        dmaengine_submit(desc);
-        dma_async_issue_pending(chan);
+        dmaengine_submit(host->dma_desc_current);
+        dma_async_issue_pending(host->dma_current);
 
         datactrl |= MCI_DPSM_DMAENABLE;
 
@@ -421,14 +457,90 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
         writel(readl(host->base + MMCIMASK0) | MCI_DATAENDMASK,
                host->base + MMCIMASK0);
         return 0;
+}
 
-unmap_exit:
-        dmaengine_terminate_all(chan);
-        dma_unmap_sg(device->dev, data->sg, data->sg_len, conf.direction);
-        return -ENOMEM;
+static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
+{
+        struct mmci_host_next *next = &host->next_data;
+
+        if (data->host_cookie && data->host_cookie != next->cookie) {
+                printk(KERN_WARNING "[%s] invalid cookie: data->host_cookie %d"
+                       " host->next_data.cookie %d\n",
+                       __func__, data->host_cookie, host->next_data.cookie);
+                data->host_cookie = 0;
+        }
+
+        if (!data->host_cookie)
+                return;
+
+        host->dma_desc_current = next->dma_desc;
+        host->dma_current = next->dma_chan;
+
+        next->dma_desc = NULL;
+        next->dma_chan = NULL;
 }
+
+static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq,
+                             bool is_first_req)
+{
+        struct mmci_host *host = mmc_priv(mmc);
+        struct mmc_data *data = mrq->data;
+        struct mmci_host_next *nd = &host->next_data;
+
+        if (!data)
+                return;
+
+        if (data->host_cookie) {
+                data->host_cookie = 0;
+                return;
+        }
+
+        /* if config for dma */
+        if (((data->flags & MMC_DATA_WRITE) && host->dma_tx_channel) ||
+            ((data->flags & MMC_DATA_READ) && host->dma_rx_channel)) {
+                if (mmci_dma_prep_data(host, data, nd))
+                        data->host_cookie = 0;
+                else
+                        data->host_cookie = ++nd->cookie < 0 ? 1 : nd->cookie;
+        }
+}
+
+static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
+                              int err)
+{
+        struct mmci_host *host = mmc_priv(mmc);
+        struct mmc_data *data = mrq->data;
+        struct dma_chan *chan;
+        enum dma_data_direction dir;
+
+        if (!data)
+                return;
+
+        if (data->flags & MMC_DATA_READ) {
+                dir = DMA_FROM_DEVICE;
+                chan = host->dma_rx_channel;
+        } else {
+                dir = DMA_TO_DEVICE;
+                chan = host->dma_tx_channel;
+        }
+
+
+        /* if config for dma */
+        if (chan) {
+                if (err)
+                        dmaengine_terminate_all(chan);
+                if (err || data->host_cookie)
+                        dma_unmap_sg(mmc_dev(host->mmc), data->sg,
+                                     data->sg_len, dir);
+                mrq->data->host_cookie = 0;
+        }
+}
+
 #else
 /* Blank functions if the DMA engine is not available */
+static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
+{
+}
 static inline void mmci_dma_setup(struct mmci_host *host)
 {
 }
@@ -449,6 +561,10 @@ static inline int mmci_dma_start_data(struct mmci_host *host, unsigned int datac
 {
         return -ENOSYS;
 }
+
+#define mmci_pre_request NULL
+#define mmci_post_request NULL
+
 #endif
 
 static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
@@ -872,6 +988,9 @@ static void mmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 
         host->mrq = mrq;
 
+        if (mrq->data)
+                mmci_get_next_data(host, mrq->data);
+
         if (mrq->data && mrq->data->flags & MMC_DATA_READ)
                 mmci_start_data(host, mrq->data);
 
@@ -986,6 +1105,8 @@ static irqreturn_t mmci_cd_irq(int irq, void *dev_id)
 
 static const struct mmc_host_ops mmci_ops = {
         .request        = mmci_request,
+        .pre_req        = mmci_pre_request,
+        .post_req       = mmci_post_request,
         .set_ios        = mmci_set_ios,
         .get_ro         = mmci_get_ro,
         .get_cd         = mmci_get_cd,
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 2164e8c6476c..79e4143ab9df 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -166,6 +166,12 @@ struct clk;
 struct variant_data;
 struct dma_chan;
 
+struct mmci_host_next {
+        struct dma_async_tx_descriptor  *dma_desc;
+        struct dma_chan                 *dma_chan;
+        s32                             cookie;
+};
+
 struct mmci_host {
         phys_addr_t             phybase;
         void __iomem            *base;
@@ -203,6 +209,8 @@ struct mmci_host {
         struct dma_chan         *dma_current;
         struct dma_chan         *dma_rx_channel;
         struct dma_chan         *dma_tx_channel;
+        struct dma_async_tx_descriptor  *dma_desc_current;
+        struct mmci_host_next   next_data;
 
 #define dma_inprogress(host)    ((host)->dma_current)
 #else