[PATCH] drivers: ddr: altera: Check IOSSM mailbox compatibility

[Naresh Kumar Ravulapalli]

Compatibility check of IOSSM mailbox with U-Boot is performed
by verifying the mailbox specification version. If check fails,
appropriate error message is displayed.

Signed-off-by: Naresh Kumar Ravulapalli <nareshkumar.ravulapalli at altera.com>
---
 drivers/ddr/altera/iossm_mailbox.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/ddr/altera/iossm_mailbox.c b/drivers/ddr/altera/iossm_mailbox.c
index 21f94959a04..2a2f86a650e 100644
--- a/drivers/ddr/altera/iossm_mailbox.c
+++ b/drivers/ddr/altera/iossm_mailbox.c
@@ -38,6 +38,8 @@
 #define IOSSM_STATUS_CMD_RESPONSE_ERROR(n)	FIELD_GET(IOSSM_STATUS_CMD_RESPONSE_ERROR_MASK, n)
 #define IOSSM_STATUS_GENERAL_ERROR_MASK		GENMASK(4, 1)
 #define IOSSM_STATUS_GENERAL_ERROR(n)		FIELD_GET(IOSSM_STATUS_GENERAL_ERROR_MASK, n)
+#define IOSSM_MAILBOX_SPEC_VERSION_MASK		GENMASK(2, 0)
+#define IOSSM_MAILBOX_SPEC_VERSION(n)		FIELD_GET(IOSSM_MAILBOX_SPEC_VERSION_MASK, n)
 
 /* Offset of Mailbox Read-only Registers  */
 #define IOSSM_MAILBOX_HEADER_OFFSET			0x0
@@ -383,6 +385,23 @@ err:
 	return ret;
 }
 
+static bool is_mailbox_spec_compatible(struct io96b_info *io96b_ctrl)
+{
+	u32 mailbox_header;
+	u8 mailbox_spec_ver;
+
+	mailbox_header = readl(io96b_ctrl->io96b[0].io96b_csr_addr +
+				IOSSM_MAILBOX_HEADER_OFFSET);
+	mailbox_spec_ver = IOSSM_MAILBOX_SPEC_VERSION(mailbox_header);
+	printf("%s: IOSSM mailbox version: %d\n", __func__, mailbox_spec_ver);
+
+	/* for now there are two mailbox spec versions, 0 and 1; only version 1 is compatible */
+	if (!mailbox_spec_ver)
+		return false;
+
+	return true;
+}
+
 /*
  * Initial function to be called to set memory interface IP type and instance ID
  * IP type and instance ID need to be determined before sending mailbox command
@@ -392,6 +411,11 @@ void io96b_mb_init(struct io96b_info *io96b_ctrl)
 	int i, j;
 	u32 mem_intf_info_0, mem_intf_info_1;
 
+	if (!is_mailbox_spec_compatible(io96b_ctrl)) {
+		printf("DDR: Failed to get compatible mailbox version\n");
+		hang();
+	}
+
 	debug("%s: num_instance %d\n", __func__, io96b_ctrl->num_instance);
 
 	for (i = 0; i < io96b_ctrl->num_instance; i++) {
-- 
2.35.3