tifm_sd: use kmap_atomic instead of kmap for PIO data buffer

Data buffer for PIO transfer used to be mapped in advance with kmap.
Abolish it in favor of on-demand kmap_atomic.

Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 25 insertions, 27 deletions

diff --git a/drivers/mmc/tifm_sd.c b/drivers/mmc/tifm_sd.c
index f22c3968f2d..3e762770afc 100644
--- a/drivers/mmc/tifm_sd.c
+++ b/drivers/mmc/tifm_sd.c
@@ -103,38 +103,51 @@ struct tifm_sd {
         wait_queue_head_t     can_eject;
 
         size_t                written_blocks;
-        char                  *buffer;
         size_t                buffer_size;
         size_t                buffer_pos;
 
 };
 
+static char* tifm_sd_kmap_atomic(struct mmc_data *data)
+{
+        return kmap_atomic(data->sg->page, KM_BIO_SRC_IRQ) + data->sg->offset;
+}
+
+static void tifm_sd_kunmap_atomic(char *buffer, struct mmc_data *data)
+{
+        kunmap_atomic(buffer - data->sg->offset, KM_BIO_SRC_IRQ);
+}
+
 static int tifm_sd_transfer_data(struct tifm_dev *sock, struct tifm_sd *host,
                                         unsigned int host_status)
 {
         struct mmc_command *cmd = host->req->cmd;
         unsigned int t_val = 0, cnt = 0;
+        char *buffer;
 
         if (host_status & TIFM_MMCSD_BRS) {
                 /* in non-dma rx mode BRS fires when fifo is still not empty */
-                if (host->buffer && (cmd->data->flags & MMC_DATA_READ)) {
+                if (no_dma && (cmd->data->flags & MMC_DATA_READ)) {
+                        buffer = tifm_sd_kmap_atomic(host->req->data);
                         while (host->buffer_size > host->buffer_pos) {
                                 t_val = readl(sock->addr + SOCK_MMCSD_DATA);
-                                host->buffer[host->buffer_pos++] = t_val & 0xff;
-                                host->buffer[host->buffer_pos++] =
+                                buffer[host->buffer_pos++] = t_val & 0xff;
+                                buffer[host->buffer_pos++] =
                                                         (t_val >> 8) & 0xff;
                         }
+                        tifm_sd_kunmap_atomic(buffer, host->req->data);
                 }
                 return 1;
-        } else if (host->buffer) {
+        } else if (no_dma) {
+                buffer = tifm_sd_kmap_atomic(host->req->data);
                 if ((cmd->data->flags & MMC_DATA_READ) &&
                                 (host_status & TIFM_MMCSD_AF)) {
                         for (cnt = 0; cnt < TIFM_MMCSD_FIFO_SIZE; cnt++) {
                                 t_val = readl(sock->addr + SOCK_MMCSD_DATA);
                                 if (host->buffer_size > host->buffer_pos) {
-                                        host->buffer[host->buffer_pos++] =
+                                        buffer[host->buffer_pos++] =
                                                         t_val & 0xff;
-                                        host->buffer[host->buffer_pos++] =
+                                        buffer[host->buffer_pos++] =
                                                         (t_val >> 8) & 0xff;
                                 }
                         }
@@ -142,14 +155,16 @@ static int tifm_sd_transfer_data(struct tifm_dev *sock, struct tifm_sd *host,
                            && (host_status & TIFM_MMCSD_AE)) {
                         for (cnt = 0; cnt < TIFM_MMCSD_FIFO_SIZE; cnt++) {
                                 if (host->buffer_size > host->buffer_pos) {
-                                        t_val = host->buffer[host->buffer_pos++] & 0x00ff;
-                                        t_val |= ((host->buffer[host->buffer_pos++]) << 8)
-                                                 & 0xff00;
+                                        t_val = buffer[host->buffer_pos++]
+                                                & 0x00ff;
+                                        t_val |= ((buffer[host->buffer_pos++])
+                                                  << 8) & 0xff00;
                                         writel(t_val,
                                                 sock->addr + SOCK_MMCSD_DATA);
                                 }
                         }
                 }
+                tifm_sd_kunmap_atomic(buffer, host->req->data);
         }
         return 0;
 }
@@ -561,15 +576,6 @@ static void tifm_sd_request_nodma(struct mmc_host *mmc, struct mmc_request *mrq)
         struct tifm_dev *sock = host->dev;
         unsigned long flags;
         struct mmc_data *r_data = mrq->cmd->data;
-        char *t_buffer = NULL;
-
-        if (r_data) {
-                t_buffer = kmap(r_data->sg->page);
-                if (!t_buffer) {
-                        printk(KERN_ERR DRIVER_NAME ": kmap failed\n");
-                        goto err_out;
-                }
-        }
 
         spin_lock_irqsave(&sock->lock, flags);
         if (host->flags & EJECT) {
@@ -586,7 +592,6 @@ static void tifm_sd_request_nodma(struct mmc_host *mmc, struct mmc_request *mrq)
         if (r_data) {
                 tifm_sd_set_data_timeout(host, r_data);
 
-                host->buffer = t_buffer + r_data->sg->offset;
                 host->buffer_size = mrq->cmd->data->blocks *
                                         mrq->cmd->data->blksz;
 
@@ -615,9 +620,6 @@ static void tifm_sd_request_nodma(struct mmc_host *mmc, struct mmc_request *mrq)
         return;
 
 err_out:
-        if (t_buffer)
-                kunmap(r_data->sg->page);
-
         mrq->cmd->error = MMC_ERR_TIMEOUT;
         mmc_request_done(mmc, mrq);
 }
@@ -659,7 +661,6 @@ static void tifm_sd_end_cmd_nodma(struct work_struct *work)
                         r_data->bytes_xfered += r_data->blksz -
                                 readl(sock->addr + SOCK_MMCSD_BLOCK_LEN) + 1;
                 }
-                host->buffer = NULL;
                 host->buffer_pos = 0;
                 host->buffer_size = 0;
         }
@@ -669,9 +670,6 @@ static void tifm_sd_end_cmd_nodma(struct work_struct *work)
 
         spin_unlock_irqrestore(&sock->lock, flags);
 
-        if (r_data)
-                kunmap(r_data->sg->page);
-
         mmc_request_done(mmc, mrq);
 }