Instead of setting up a kernel pointer to track the current PIO address,
track the offset in the current page, and do an atomic kmap for the page
while doing the actual PIO operations.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/mmc/host/s3cmci.c | 107 +++++++++++++++++++-------------------
 drivers/mmc/host/s3cmci.h |   3 +-
 2 files changed, 55 insertions(+), 55 deletions(-)

diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index 10f5219b3b40..989fefea19f1 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -317,26 +317,17 @@ static void s3cmci_check_sdio_irq(struct s3cmci_host 
*host)
        }
 }
 
-static inline int get_data_buffer(struct s3cmci_host *host,
-                                 u32 *bytes, u32 **pointer)
+static inline int get_data_buffer(struct s3cmci_host *host)
 {
-       struct scatterlist *sg;
-
-       if (host->pio_active == XFER_NONE)
-               return -EINVAL;
-
-       if ((!host->mrq) || (!host->mrq->data))
-               return -EINVAL;
-
        if (host->pio_sgptr >= host->mrq->data->sg_len) {
                dbg(host, dbg_debug, "no more buffers (%i/%i)\n",
                      host->pio_sgptr, host->mrq->data->sg_len);
                return -EBUSY;
        }
-       sg = &host->mrq->data->sg[host->pio_sgptr];
+       host->cur_sg = &host->mrq->data->sg[host->pio_sgptr];
 
-       *bytes = sg->length;
-       *pointer = sg_virt(sg);
+       host->pio_bytes = host->cur_sg->length;
+       host->pio_offset = host->cur_sg->offset;
 
        host->pio_sgptr++;
 
@@ -422,11 +413,16 @@ static void s3cmci_disable_irq(struct s3cmci_host *host, 
bool transfer)
 
 static void do_pio_read(struct s3cmci_host *host)
 {
-       int res;
        u32 fifo;
        u32 *ptr;
        u32 fifo_words;
        void __iomem *from_ptr;
+       void *buf;
+
+       if (host->pio_active == XFER_NONE)
+               goto done;
+       if (!host->mrq || !host->mrq->data)
+               goto done;
 
        /* write real prescaler to host, it might be set slow to fix */
        writel(host->prescaler, host->base + S3C2410_SDIPRE);
@@ -435,20 +431,12 @@ static void do_pio_read(struct s3cmci_host *host)
 
        while ((fifo = fifo_count(host))) {
                if (!host->pio_bytes) {
-                       res = get_data_buffer(host, &host->pio_bytes,
-                                             &host->pio_ptr);
-                       if (res) {
-                               host->pio_active = XFER_NONE;
-                               host->complete_what = COMPLETION_FINALIZE;
-
-                               dbg(host, dbg_pio, "pio_read(): "
-                                   "complete (no more data).\n");
-                               return;
-                       }
+                       if (get_data_buffer(host) < 0)
+                               goto done;
 
                        dbg(host, dbg_pio,
-                           "pio_read(): new target: [%i]@[%p]\n",
-                           host->pio_bytes, host->pio_ptr);
+                           "pio_read(): new target: [%i]@[%zu]\n",
+                           host->pio_bytes, host->pio_offset);
                }
 
                dbg(host, dbg_pio,
@@ -470,63 +458,65 @@ static void do_pio_read(struct s3cmci_host *host)
                host->pio_count += fifo;
 
                fifo_words = fifo >> 2;
-               ptr = host->pio_ptr;
-               while (fifo_words--)
+
+               buf = (sg_kmap_atomic(host->cur_sg) + host->pio_offset);
+               ptr = buf;
+               while (fifo_words--) {
                        *ptr++ = readl(from_ptr);
-               host->pio_ptr = ptr;
+                       host->pio_offset += 4;
+               }
 
                if (fifo & 3) {
                        u32 n = fifo & 3;
                        u32 data = readl(from_ptr);
-                       u8 *p = (u8 *)host->pio_ptr;
+                       u8 *p = (u8 *)ptr;
 
                        while (n--) {
                                *p++ = data;
                                data >>= 8;
+                               host->pio_offset++;
                        }
                }
+               sg_kunmap_atomic(host->cur_sg, buf);
        }
 
        if (!host->pio_bytes) {
-               res = get_data_buffer(host, &host->pio_bytes, &host->pio_ptr);
-               if (res) {
-                       dbg(host, dbg_pio,
-                           "pio_read(): complete (no more buffers).\n");
-                       host->pio_active = XFER_NONE;
-                       host->complete_what = COMPLETION_FINALIZE;
-
-                       return;
-               }
+               if (get_data_buffer(host) < 0)
+                       goto done;
        }
 
        enable_imask(host,
                     S3C2410_SDIIMSK_RXFIFOHALF | S3C2410_SDIIMSK_RXFIFOLAST);
+       return;
+
+done:
+       host->pio_active = XFER_NONE;
+       host->complete_what = COMPLETION_FINALIZE;
+       dbg(host, dbg_pio, "pio_read(): complete (no more data).\n");
 }
 
 static void do_pio_write(struct s3cmci_host *host)
 {
        void __iomem *to_ptr;
-       int res;
+       void *buf;
        u32 fifo;
        u32 *ptr;
 
+       if (host->pio_active == XFER_NONE)
+               goto done;
+       if (!host->mrq || !host->mrq->data)
+               goto done;
+
        to_ptr = host->base + host->sdidata;
 
        while ((fifo = fifo_free(host)) > 3) {
                if (!host->pio_bytes) {
-                       res = get_data_buffer(host, &host->pio_bytes,
-                                                       &host->pio_ptr);
-                       if (res) {
-                               dbg(host, dbg_pio,
-                                   "pio_write(): complete (no more data).\n");
-                               host->pio_active = XFER_NONE;
-
-                               return;
-                       }
+                       if (get_data_buffer(host) < 0)
+                               goto done;
 
                        dbg(host, dbg_pio,
-                           "pio_write(): new source: [%i]@[%p]\n",
-                           host->pio_bytes, host->pio_ptr);
+                           "pio_write(): new source: [%i]@[%zd]\n",
+                           host->pio_bytes, host->pio_offset);
 
                }
 
@@ -543,13 +533,20 @@ static void do_pio_write(struct s3cmci_host *host)
                host->pio_count += fifo;
 
                fifo = (fifo + 3) >> 2;
-               ptr = host->pio_ptr;
-               while (fifo--)
+               buf = (sg_kmap_atomic(host->cur_sg) + host->pio_offset);
+               ptr = buf;
+               while (fifo--) {
                        writel(*ptr++, to_ptr);
-               host->pio_ptr = ptr;
+                       host->pio_offset += 4;
+               }
+               sg_kunmap_atomic(host->cur_sg, buf);
        }
 
        enable_imask(host, S3C2410_SDIIMSK_TXFIFOHALF);
+       return;
+done:
+       dbg(host, dbg_pio, "pio_write(): complete (no more data).\n");
+       host->pio_active = XFER_NONE;
 }
 
 static void pio_tasklet(unsigned long data)
@@ -1055,6 +1052,7 @@ static int s3cmci_prepare_pio(struct s3cmci_host *host, 
struct mmc_data *data)
        BUG_ON((data->flags & BOTH_DIR) == BOTH_DIR);
 
        host->pio_sgptr = 0;
+       host->cur_sg = &host->mrq->data->sg[host->pio_sgptr];
        host->pio_bytes = 0;
        host->pio_count = 0;
        host->pio_active = rw ? XFER_WRITE : XFER_READ;
@@ -1678,6 +1676,7 @@ static int s3cmci_probe(struct platform_device *pdev)
        host->clk_rate = clk_get_rate(host->clk);
 
        mmc->ops        = &s3cmci_ops;
+       mmc->need_kmap  = 1;
        mmc->ocr_avail  = MMC_VDD_32_33 | MMC_VDD_33_34;
 #ifdef CONFIG_MMC_S3C_HW_SDIO_IRQ
        mmc->caps       = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
diff --git a/drivers/mmc/host/s3cmci.h b/drivers/mmc/host/s3cmci.h
index 30c2c0dd1bc8..4320f7d832dc 100644
--- a/drivers/mmc/host/s3cmci.h
+++ b/drivers/mmc/host/s3cmci.h
@@ -50,10 +50,11 @@ struct s3cmci_host {
 
        int                     dma_complete;
 
+       struct scatterlist      *cur_sg;
        u32                     pio_sgptr;
        u32                     pio_bytes;
        u32                     pio_count;
-       u32                     *pio_ptr;
+       u32                     pio_offset;
 #define XFER_NONE 0
 #define XFER_READ 1
 #define XFER_WRITE 2
-- 
2.20.1

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