From: Alexandre Courbot <acourbot@xxxxxxxxxxxx>
When running memcpy_toio:
memcpy_toio(send_obj->share_buf, buf, len);
it was found that errors appear if len is not a multiple of 8:
[58.350841] mtk-mdp 14001000.rdma: processing failed: -22
This is because in ARM64, memcpy_toio does byte-size access
when the length is not a multiple of 8 while access to the
vpu iomem must be 4 aligned.
This patch ensures the copy of a multiple of 8 size by calling
round_up(len, 8) when copying
Fixes: e6599adfad30 ("media: mtk-vpu: avoid unaligned access to DTCM buffer.")
Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxxxx>
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
Reviewed-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
---
changes since v4:
1. replace data[SHARE_BUF_SIZE]; with data[sizeof(send_obj->share_buf)]
2. Add the explanation for the failure in commit log and inline doc
changes since v3:
1. multile -> multiple
2. add inline doc
changes since v2:
1. do the extra copy only if len is not multiple of 8
changes since v1:
1. change sign-off-by tags
2. change values to memset
drivers/media/platform/mtk-vpu/mtk_vpu.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c
index 7f1647da0ade..2ef93db239b9 100644
--- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
+++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
@@ -349,7 +349,22 @@ int vpu_ipi_send(struct platform_device *pdev,
}
} while (vpu_cfg_readl(vpu, HOST_TO_VPU));
- memcpy_toio(send_obj->share_buf, buf, len);
+ /*
+ * On Arm64, the memcpy_toio does byte-size access as long as address or length are
+ * not 8 aligned. Access to the vpu iomem must be 4 aligned. Byte-size access is
+ * not allowed and cause processing to fail. Therefore make sure the length
+ * sent to memcpy_toio is a multiply of 8.
+ */
+ if (len % 8 != 0) {
+ unsigned char data[sizeof(send_obj->share_buf)];
+
+ memset(data + len, 0, sizeof(data) - len);
+ memcpy(data, buf, len);
+ memcpy_toio(send_obj->share_buf, data, round_up(len, 8));
+ } else {
+ memcpy_toio(send_obj->share_buf, buf, len);
+ }
+
writel(len, &send_obj->len);
writel(id, &send_obj->id);
--
2.17.1
