From: Yi Li <[EMAIL PROTECTED]>
Signed-off-by: Yi Li <[EMAIL PROTECTED]>
Signed-off-by: Bryan Wu <[EMAIL PROTECTED]>
---
drivers/spi/spi_bfin5xx.c | 81 +++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 78 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 0e3102a..28dd0fe 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -45,6 +45,8 @@ MODULE_LICENSE("GPL");
#define QUEUE_RUNNING 0
#define QUEUE_STOPPED 1
+#define BFIN_SPI_LOCK 1
+
struct driver_data {
/* Driver model hookup */
struct platform_device *pdev;
@@ -68,7 +70,10 @@ struct driver_data {
struct list_head queue;
int busy;
int run;
-
+#ifdef BFIN_SPI_LOCK
+ /* SPI bus is lock by a slave for exclusive access */
+ int locked;
+#endif
/* Message Transfer pump */
struct tasklet_struct pump_transfers;
@@ -932,6 +937,10 @@ static void pump_messages(struct work_struct *work)
{
struct driver_data *drv_data;
unsigned long flags;
+#ifdef BFIN_SPI_LOCK
+ int locked_cs = -1;
+ struct spi_message *next_msg = NULL, *msg = NULL;
+#endif
drv_data = container_of(work, struct driver_data, pump_messages);
@@ -950,10 +959,35 @@ static void pump_messages(struct work_struct *work)
return;
}
+#ifdef BFIN_SPI_LOCK
+ /* Extract head of queue */
+ next_msg = list_entry(drv_data->queue.next,
+ struct spi_message, queue);
+
+ if (drv_data->locked)
+ locked_cs = drv_data->locked;
+
+ /* Someone has locked the bus */
+ if (drv_data->locked && next_msg->spi->chip_select != locked_cs) {
+ list_for_each_entry(msg, &drv_data->queue, queue) {
+ if (msg->spi->chip_select == locked_cs) {
+ next_msg = msg;
+ break;
+ }
+ }
+ /* Do nothing even if there are messages for other devices */
+ if (next_msg->spi->chip_select != locked_cs) {
+ drv_data->busy = 0;
+ spin_unlock_irqrestore(&drv_data->lock, flags);
+ return;
+ }
+ }
+ drv_data->cur_msg = next_msg;
+#else
/* Extract head of queue */
drv_data->cur_msg = list_entry(drv_data->queue.next,
- struct spi_message, queue);
-
+ struct spi_message, queue);
+#endif
/* Setup the SSP using the per chip configuration */
drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi);
restore_state(drv_data);
@@ -982,6 +1016,39 @@ static void pump_messages(struct work_struct *work)
}
/*
+ * lock the spi bus for exclusive access
+ */
+static int lock_bus(struct spi_device *spi)
+{
+#ifdef BFIN_SPI_LOCK
+ struct driver_data *drv_data = spi_master_get_devdata(spi->master);
+ unsigned long flags;
+
+ spin_lock_irqsave(&drv_data->lock, flags);
+ if (drv_data->locked) {
+ spin_unlock_irqrestore(&drv_data->lock, flags);
+ return -ENOLCK;
+ }
+ drv_data->locked = spi->chip_select;
+ spin_unlock_irqrestore(&drv_data->lock, flags);
+#endif
+ return 0;
+}
+
+static int unlock_bus(struct spi_device *spi)
+{
+#ifdef BFIN_SPI_LOCK
+ struct driver_data *drv_data = spi_master_get_devdata(spi->master);
+ unsigned long flags;
+
+ spin_lock_irqsave(&drv_data->lock, flags);
+ drv_data->locked = 0;
+ spin_unlock_irqrestore(&drv_data->lock, flags);
+#endif
+ return 0;
+}
+
+/*
* got a msg to transfer, queue it in drv_data->queue.
* And kick off message pumper
*/
@@ -1188,6 +1255,9 @@ static inline int init_queue(struct driver_data *drv_data)
INIT_LIST_HEAD(&drv_data->queue);
spin_lock_init(&drv_data->lock);
+#ifdef BFIN_SPI_LOCK
+ drv_data->locked = 0;
+#endif
drv_data->run = QUEUE_STOPPED;
drv_data->busy = 0;
@@ -1235,6 +1305,9 @@ static inline int stop_queue(struct driver_data *drv_data)
spin_lock_irqsave(&drv_data->lock, flags);
+#ifdef BFIN_SPI_LOCK
+ drv_data->locked = 0;
+#endif
/*
* This is a bit lame, but is optimized for the common execution path.
* A wait_queue on the drv_data->busy could be used, but then the common
@@ -1298,6 +1371,8 @@ static int __init bfin5xx_spi_probe(struct
platform_device *pdev)
master->cleanup = cleanup;
master->setup = setup;
master->transfer = transfer;
+ master->lock_bus = lock_bus;
+ master->unlock_bus = unlock_bus;
/* Find and map our resources */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
--
1.5.6.3
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