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-rw-r--r--target/linux/layerscape/patches-4.14/825-vfio-fsl-mc-Improve-send-mc-command-and-read-respons.patch48
1 files changed, 48 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-4.14/825-vfio-fsl-mc-Improve-send-mc-command-and-read-respons.patch b/target/linux/layerscape/patches-4.14/825-vfio-fsl-mc-Improve-send-mc-command-and-read-respons.patch
new file mode 100644
index 0000000000..c04fef044c
--- /dev/null
+++ b/target/linux/layerscape/patches-4.14/825-vfio-fsl-mc-Improve-send-mc-command-and-read-respons.patch
@@ -0,0 +1,48 @@
+From 703b2ca94467a029942fa478a38f0a14c8109766 Mon Sep 17 00:00:00 2001
+From: Bharat Bhushan <bharat.bhushan@nxp.com>
+Date: Fri, 1 Mar 2019 13:33:58 +0800
+Subject: [PATCH] vfio/fsl-mc: Improve send mc-command and read response
+
+Actually there is no ordering need when reading response
+from mc-portal. Similarly when writing the mc-command,
+ordering needed before command is submitted.
+
+This patch removes un-necessary barriers, response is read
+relaxed and maintain ordering when submit command. This also
+fixes compilation issue with newer kernel.
+
+Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
+Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
+---
+ drivers/vfio/fsl-mc/vfio_fsl_mc.c | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
++++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+@@ -331,9 +331,7 @@ static int vfio_fsl_mc_dprc_wait_for_res
+ u64 header;
+ struct mc_cmd_header *resp_hdr;
+
+- __iormb();
+- header = readq(ioaddr);
+- __iormb();
++ header = cpu_to_le64(readq_relaxed(ioaddr));
+
+ resp_hdr = (struct mc_cmd_header *)&header;
+ status = (enum mc_cmd_status)resp_hdr->status;
+@@ -353,9 +351,12 @@ static int vfio_fsl_mc_send_command(void
+ {
+ int i;
+
+- /* Write at command header in the end */
+- for (i = 7; i >= 0; i--)
+- writeq(cmd_data[i], ioaddr + i * sizeof(uint64_t));
++ /* Write at command parameter into portal */
++ for (i = 7; i >= 1; i--)
++ writeq_relaxed(cmd_data[i], ioaddr + i * sizeof(uint64_t));
++
++ /* Write command header in the end */
++ writeq(cmd_data[0], ioaddr);
+
+ /* Wait for response before returning to user-space
+ * This can be optimized in future to even prepare response