2 files changed, 79 insertions, 71 deletions

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 0e342793ff14..8bec1c36b159 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -22,7 +22,6 @@
 #include <linux/ioport.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
-#include <linux/scatterlist.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/stat.h>
@@ -502,8 +501,14 @@ static void dw_mci_submit_data(struct dw_mci *host, struct mmc_data *data)
                 host->dir_status = DW_MCI_SEND_STATUS;
 
         if (dw_mci_submit_data_dma(host, data)) {
+                int flags = SG_MITER_ATOMIC;
+                if (host->data->flags & MMC_DATA_READ)
+                        flags |= SG_MITER_TO_SG;
+                else
+                        flags |= SG_MITER_FROM_SG;
+
+                sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
                 host->sg = data->sg;
-                host->pio_offset = 0;
                 host->part_buf_start = 0;
                 host->part_buf_count = 0;
 
@@ -972,6 +977,7 @@ static void dw_mci_tasklet_func(unsigned long priv)
                                  * generates a block interrupt, hence setting
                                  * the scatter-gather pointer to NULL.
                                  */
+                                sg_miter_stop(&host->sg_miter);
                                 host->sg = NULL;
                                 ctrl = mci_readl(host, CTRL);
                                 ctrl |= SDMMC_CTRL_FIFO_RESET;
@@ -1311,54 +1317,44 @@ static void dw_mci_pull_data(struct dw_mci *host, void *buf, int cnt)
 
 static void dw_mci_read_data_pio(struct dw_mci *host)
 {
-        struct scatterlist *sg = host->sg;
-        void *buf = sg_virt(sg);
-        unsigned int offset = host->pio_offset;
+        struct sg_mapping_iter *sg_miter = &host->sg_miter;
+        void *buf;
+        unsigned int offset;
         struct mmc_data *data = host->data;
         int shift = host->data_shift;
         u32 status;
         unsigned int nbytes = 0, len;
+        unsigned int remain, fcnt;
 
         do {
-                len = host->part_buf_count +
-                        (SDMMC_GET_FCNT(mci_readl(host, STATUS)) << shift);
-                if (offset + len <= sg->length) {
+                if (!sg_miter_next(sg_miter))
+                        goto done;
+
+                host->sg = sg_miter->__sg;
+                buf = sg_miter->addr;
+                remain = sg_miter->length;
+                offset = 0;
+
+                do {
+                        fcnt = (SDMMC_GET_FCNT(mci_readl(host, STATUS))
+                                        << shift) + host->part_buf_count;
+                        len = min(remain, fcnt);
+                        if (!len)
+                                break;
                         dw_mci_pull_data(host, (void *)(buf + offset), len);
-
                         offset += len;
                         nbytes += len;
-
-                        if (offset == sg->length) {
-                                flush_dcache_page(sg_page(sg));
-                                host->sg = sg = sg_next(sg);
-                                if (!sg)
-                                        goto done;
-
-                                offset = 0;
-                                buf = sg_virt(sg);
-                        }
-                } else {
-                        unsigned int remaining = sg->length - offset;
-                        dw_mci_pull_data(host, (void *)(buf + offset),
-                                         remaining);
-                        nbytes += remaining;
-
-                        flush_dcache_page(sg_page(sg));
-                        host->sg = sg = sg_next(sg);
-                        if (!sg)
-                                goto done;
-
-                        offset = len - remaining;
-                        buf = sg_virt(sg);
-                        dw_mci_pull_data(host, buf, offset);
-                        nbytes += offset;
-                }
+                        remain -= len;
+                } while (remain);
+                sg_miter->consumed = offset;
 
                 status = mci_readl(host, MINTSTS);
                 mci_writel(host, RINTSTS, SDMMC_INT_RXDR);
                 if (status & DW_MCI_DATA_ERROR_FLAGS) {
                         host->data_status = status;
                         data->bytes_xfered += nbytes;
+                        sg_miter_stop(sg_miter);
+                        host->sg = NULL;
                         smp_wmb();
 
                         set_bit(EVENT_DATA_ERROR, &host->pending_events);
@@ -1367,65 +1363,66 @@ static void dw_mci_read_data_pio(struct dw_mci *host)
                         return;
                 }
         } while (status & SDMMC_INT_RXDR); /*if the RXDR is ready read again*/
-        host->pio_offset = offset;
         data->bytes_xfered += nbytes;
+
+        if (!remain) {
+                if (!sg_miter_next(sg_miter))
+                        goto done;
+                sg_miter->consumed = 0;
+        }
+        sg_miter_stop(sg_miter);
         return;
 
 done:
         data->bytes_xfered += nbytes;
+        sg_miter_stop(sg_miter);
+        host->sg = NULL;
         smp_wmb();
         set_bit(EVENT_XFER_COMPLETE, &host->pending_events);
 }
 
 static void dw_mci_write_data_pio(struct dw_mci *host)
 {
-        struct scatterlist *sg = host->sg;
-        void *buf = sg_virt(sg);
-        unsigned int offset = host->pio_offset;
+        struct sg_mapping_iter *sg_miter = &host->sg_miter;
+        void *buf;
+        unsigned int offset;
         struct mmc_data *data = host->data;
         int shift = host->data_shift;
         u32 status;
         unsigned int nbytes = 0, len;
+        unsigned int fifo_depth = host->fifo_depth;
+        unsigned int remain, fcnt;
 
         do {
-                len = ((host->fifo_depth -
-                        SDMMC_GET_FCNT(mci_readl(host, STATUS))) << shift)
-                        - host->part_buf_count;
-                if (offset + len <= sg->length) {
+                if (!sg_miter_next(sg_miter))
+                        goto done;
+
+                host->sg = sg_miter->__sg;
+                buf = sg_miter->addr;
+                remain = sg_miter->length;
+                offset = 0;
+
+                do {
+                        fcnt = ((fifo_depth -
+                                 SDMMC_GET_FCNT(mci_readl(host, STATUS)))
+                                        << shift) - host->part_buf_count;
+                        len = min(remain, fcnt);
+                        if (!len)
+                                break;
                         host->push_data(host, (void *)(buf + offset), len);
-
                         offset += len;
                         nbytes += len;
-                        if (offset == sg->length) {
-                                host->sg = sg = sg_next(sg);
-                                if (!sg)
-                                        goto done;
-
-                                offset = 0;
-                                buf = sg_virt(sg);
-                        }
-                } else {
-                        unsigned int remaining = sg->length - offset;
-
-                        host->push_data(host, (void *)(buf + offset),
-                                        remaining);
-                        nbytes += remaining;
-
-                        host->sg = sg = sg_next(sg);
-                        if (!sg)
-                                goto done;
-
-                        offset = len - remaining;
-                        buf = sg_virt(sg);
-                        host->push_data(host, (void *)buf, offset);
-                        nbytes += offset;
-                }
+                        remain -= len;
+                } while (remain);
+                sg_miter->consumed = offset;
 
                 status = mci_readl(host, MINTSTS);
                 mci_writel(host, RINTSTS, SDMMC_INT_TXDR);
                 if (status & DW_MCI_DATA_ERROR_FLAGS) {
                         host->data_status = status;
                         data->bytes_xfered += nbytes;
+                        sg_miter_stop(sg_miter);
+                        host->sg = NULL;
 
                         smp_wmb();
 
@@ -1435,12 +1432,20 @@ static void dw_mci_write_data_pio(struct dw_mci *host)
                         return;
                 }
         } while (status & SDMMC_INT_TXDR); /* if TXDR write again */
-        host->pio_offset = offset;
         data->bytes_xfered += nbytes;
+
+        if (!remain) {
+                if (!sg_miter_next(sg_miter))
+                        goto done;
+                sg_miter->consumed = 0;
+        }
+        sg_miter_stop(sg_miter);
         return;
 
 done:
         data->bytes_xfered += nbytes;
+        sg_miter_stop(sg_miter);
+        host->sg = NULL;
         smp_wmb();
         set_bit(EVENT_XFER_COMPLETE, &host->pending_events);
 }
@@ -1643,6 +1648,7 @@ static void dw_mci_work_routine_card(struct work_struct *work)
                                  * block interrupt, hence setting the
                                  * scatter-gather pointer to NULL.
                                  */
+                                sg_miter_stop(&host->sg_miter);
                                 host->sg = NULL;
 
                                 ctrl = mci_readl(host, CTRL);
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index e8779c6d1759..aae5d1f1bb39 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -14,6 +14,8 @@
 #ifndef LINUX_MMC_DW_MMC_H
 #define LINUX_MMC_DW_MMC_H
 
+#include <linux/scatterlist.h>
+
 #define MAX_MCI_SLOTS   2
 
 enum dw_mci_state {
@@ -40,7 +42,7 @@ struct mmc_data;
  * @lock: Spinlock protecting the queue and associated data.
  * @regs: Pointer to MMIO registers.
  * @sg: Scatterlist entry currently being processed by PIO code, if any.
- * @pio_offset: Offset into the current scatterlist entry.
+ * @sg_miter: PIO mapping scatterlist iterator.
  * @cur_slot: The slot which is currently using the controller.
  * @mrq: The request currently being processed on @cur_slot,
  *      or NULL if the controller is idle.
@@ -115,7 +117,7 @@ struct dw_mci {
         void __iomem            *regs;
 
         struct scatterlist      *sg;
-        unsigned int            pio_offset;
+        struct sg_mapping_iter  sg_miter;
 
         struct dw_mci_slot      *cur_slot;
         struct mmc_request      *mrq;