1 files changed, 11 insertions, 48 deletions

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index ad847a24a675..dfc290dd43a3 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -182,7 +182,7 @@ mmc_spi_readbytes(struct mmc_spi_host *host, unsigned len)
                                 host->data_dma, sizeof(*host->data),
                                 DMA_FROM_DEVICE);
 
-        status = spi_sync(host->spi, &host->readback);
+        status = spi_sync_locked(host->spi, &host->readback);
 
         if (host->dma_dev)
                 dma_sync_single_for_cpu(host->dma_dev,
@@ -541,7 +541,7 @@ mmc_spi_command_send(struct mmc_spi_host *host,
                                 host->data_dma, sizeof(*host->data),
                                 DMA_BIDIRECTIONAL);
         }
-        status = spi_sync(host->spi, &host->m);
+        status = spi_sync_locked(host->spi, &host->m);
 
         if (host->dma_dev)
                 dma_sync_single_for_cpu(host->dma_dev,
@@ -685,7 +685,7 @@ mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t,
                                 host->data_dma, sizeof(*scratch),
                                 DMA_BIDIRECTIONAL);
 
-        status = spi_sync(spi, &host->m);
+        status = spi_sync_locked(spi, &host->m);
 
         if (status != 0) {
                 dev_dbg(&spi->dev, "write error (%d)\n", status);
@@ -822,7 +822,7 @@ mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t,
                                 DMA_FROM_DEVICE);
         }
 
-        status = spi_sync(spi, &host->m);
+        status = spi_sync_locked(spi, &host->m);
 
         if (host->dma_dev) {
                 dma_sync_single_for_cpu(host->dma_dev,
@@ -1018,7 +1018,7 @@ mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd,
                                         host->data_dma, sizeof(*scratch),
                                         DMA_BIDIRECTIONAL);
 
-                tmp = spi_sync(spi, &host->m);
+                tmp = spi_sync_locked(spi, &host->m);
 
                 if (host->dma_dev)
                         dma_sync_single_for_cpu(host->dma_dev,
@@ -1084,6 +1084,9 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
         }
 #endif
 
+        /* request exclusive bus access */
+        spi_bus_lock(host->spi->master);
+
         /* issue command; then optionally data and stop */
         status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
         if (status == 0 && mrq->data) {
@@ -1094,6 +1097,9 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
                         mmc_cs_off(host);
         }
 
+        /* release the bus */
+        spi_bus_unlock(host->spi->master);
+
         mmc_request_done(host->mmc, mrq);
 }
 
@@ -1290,23 +1296,6 @@ mmc_spi_detect_irq(int irq, void *mmc)
         return IRQ_HANDLED;
 }
 
-struct count_children {
-        unsigned        n;
-        struct bus_type *bus;
-};
-
-static int maybe_count_child(struct device *dev, void *c)
-{
-        struct count_children *ccp = c;
-
-        if (dev->bus == ccp->bus) {
-                if (ccp->n)
-                        return -EBUSY;
-                ccp->n++;
-        }
-        return 0;
-}
-
 static int mmc_spi_probe(struct spi_device *spi)
 {
         void                    *ones;
@@ -1338,32 +1327,6 @@ static int mmc_spi_probe(struct spi_device *spi)
                 return status;
         }
 
-        /* We can use the bus safely iff nobody else will interfere with us.
-         * Most commands consist of one SPI message to issue a command, then
-         * several more to collect its response, then possibly more for data
-         * transfer.  Clocking access to other devices during that period will
-         * corrupt the command execution.
-         *
-         * Until we have software primitives which guarantee non-interference,
-         * we'll aim for a hardware-level guarantee.
-         *
-         * REVISIT we can't guarantee another device won't be added later...
-         */
-        if (spi->master->num_chipselect > 1) {
-                struct count_children cc;
-
-                cc.n = 0;
-                cc.bus = spi->dev.bus;
-                status = device_for_each_child(spi->dev.parent, &cc,
-                                maybe_count_child);
-                if (status < 0) {
-                        dev_err(&spi->dev, "can't share SPI bus\n");
-                        return status;
-                }
-
-                dev_warn(&spi->dev, "ASSUMING SPI bus stays unshared!\n");
-        }
-
         /* We need a supply of ones to transmit.  This is the only time
          * the CPU touches these, so cache coherency isn't a concern.
          *