plat: xilinx: Add timeout while waiting for IPI Ack

Return timeout error if, IPI is not acked in specified timeout.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Change-Id: I27be3d4d4eb5bc57f6a84c839e2586278c0aec19

plat/xilinx/common/include/ipi.h

@@ -63,7 +63,7 @@ void ipi_mb_release(uint32_t local, uint32_t remote);
 int ipi_mb_enquire_status(uint32_t local, uint32_t remote);
 
 /* Trigger notification on the IPI mailbox */
-void ipi_mb_notify(uint32_t local, uint32_t remote, uint32_t is_blocking);
+int ipi_mb_notify(uint32_t local, uint32_t remote, uint32_t is_blocking);
 
 /* Ack IPI mailbox notification */
 void ipi_mb_ack(uint32_t local, uint32_t remote);

plat/xilinx/common/ipi.c

@@ -13,6 +13,7 @@
 
 #include <common/debug.h>
 #include <common/runtime_svc.h>
+#include <drivers/delay_timer.h>
 #include <lib/bakery_lock.h>
 #include <lib/mmio.h>
 
@@ -38,6 +39,9 @@
 /* IPI register bit mask */
 #define IPI_BIT_MASK(I) (ipi_table[(I)].ipi_bit_mask)
 
+/* IPI Timeout */
+#define TIMEOUT_COUNT_US	U(0x4000)
+
 /* IPI configuration table */
 const static struct ipi_config *ipi_table;
 
@@ -156,21 +160,30 @@ int ipi_mb_enquire_status(uint32_t local, uint32_t remote)
  * @remote - remote IPI ID
  * @is_blocking - if to trigger the notification in blocking mode or not.
  *
+ * return - 0 - Success or Error incase of timeout
  * It sets the remote bit in the IPI agent trigger register.
  *
  */
-void ipi_mb_notify(uint32_t local, uint32_t remote, uint32_t is_blocking)
+int ipi_mb_notify(uint32_t local, uint32_t remote, uint32_t is_blocking)
 {
 	uint32_t status;
+	const unsigned int timeout_count = TIMEOUT_COUNT_US;
+	uint64_t timeout;
 
 	mmio_write_32(IPI_REG_BASE(local) + IPI_TRIG_OFFSET,
 		      IPI_BIT_MASK(remote));
 	if (is_blocking) {
+		timeout = timeout_init_us(timeout_count);
 		do {
 			status = mmio_read_32(IPI_REG_BASE(local) +
 					      IPI_OBR_OFFSET);
+			if (timeout_elapsed(timeout)) {
+				return -ETIMEDOUT;
+			}
 		} while (status & IPI_BIT_MASK(remote));
 	}
+
+	return 0;
 }
 
 /* ipi_mb_ack() - Ack IPI mailbox notification from the other end

plat/xilinx/common/ipi_mailbox_service/ipi_mailbox_svc.c

@@ -107,8 +107,8 @@ uint64_t ipi_smc_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2,
 		uint32_t is_blocking;
 
 		is_blocking = (x3 & IPI_SMC_NOTIFY_BLOCK_MASK) ? 1 : 0;
-		ipi_mb_notify(ipi_local_id, ipi_remote_id, is_blocking);
-		SMC_RET1(handle, 0);
+		ret = ipi_mb_notify(ipi_local_id, ipi_remote_id, is_blocking);
+		SMC_RET1(handle, ret);
 	}
 	case IPI_MAILBOX_ACK:
 	{

plat/xilinx/common/pm_service/pm_ipi.c

@@ -55,6 +55,7 @@ static enum pm_ret_status pm_ipi_send_common(const struct pm_proc *proc,
 					     uint32_t payload[PAYLOAD_ARG_CNT],
 					     uint32_t is_blocking)
 {
+	int status;
 	unsigned int offset = 0;
 	uintptr_t buffer_base = proc->ipi->buffer_base +
 					IPI_BUFFER_TARGET_REMOTE_OFFSET +
@@ -70,10 +71,13 @@ static enum pm_ret_status pm_ipi_send_common(const struct pm_proc *proc,
 	}
 
 	/* Generate IPI to remote processor */
-	ipi_mb_notify(proc->ipi->local_ipi_id, proc->ipi->remote_ipi_id,
+	status = ipi_mb_notify(proc->ipi->local_ipi_id, proc->ipi->remote_ipi_id,
 		      is_blocking);
+	if (status == 0) {
+		return PM_RET_SUCCESS;
+	}
 
-	return PM_RET_SUCCESS;
+	return PM_RET_ERROR_TIMEOUT;
 }
 
 /**