sata_sil24: Use memory barriers before issuing commands
The data in the cmd_block buffers may reach the main memory after the
writel() to the device ports. This patch introduces two calls to wmb()
to ensure the relative ordering.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Colin Tuckley <colin.tuckley@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index a7f0139..be7726d 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -622,6 +622,11 @@
irq_enabled = readl(port + PORT_IRQ_ENABLE_SET);
writel(PORT_IRQ_COMPLETE | PORT_IRQ_ERROR, port + PORT_IRQ_ENABLE_CLR);
+ /*
+ * The barrier is required to ensure that writes to cmd_block reach
+ * the memory before the write to PORT_CMD_ACTIVATE.
+ */
+ wmb();
writel((u32)paddr, port + PORT_CMD_ACTIVATE);
writel((u64)paddr >> 32, port + PORT_CMD_ACTIVATE + 4);
@@ -895,6 +900,11 @@
paddr = pp->cmd_block_dma + tag * sizeof(*pp->cmd_block);
activate = port + PORT_CMD_ACTIVATE + tag * 8;
+ /*
+ * The barrier is required to ensure that writes to cmd_block reach
+ * the memory before the write to PORT_CMD_ACTIVATE.
+ */
+ wmb();
writel((u32)paddr, activate);
writel((u64)paddr >> 32, activate + 4);