[PATCH v2 8/8] bus: mhi: core: Ensure non-zero session or sequence ID values

Bhaumik Bhatt
2020-04-28T03:00:05Z

While writing any sequence or session identifiers, it is possible that
the host could write a zero value, whereas only non-zero values are
supported writes to those registers. Ensure that host does not write a
non-zero value for those cases.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
---
drivers/bus/mhi/core/boot.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
index 0bc9c50..c9971d4 100644
--- a/drivers/bus/mhi/core/boot.c
+++ b/drivers/bus/mhi/core/boot.c
@@ -199,6 +199,9 @@ static int mhi_fw_load_amss(struct mhi_controller *mhi_cntrl,
mhi_write_reg(mhi_cntrl, base, BHIE_TXVECSIZE_OFFS, mhi_buf->len);

sequence_id = prandom_u32() & BHIE_TXVECSTATUS_SEQNUM_BMSK;
+ if (unlikely(!sequence_id))
+ sequence_id = 1;
+
mhi_write_reg_field(mhi_cntrl, base, BHIE_TXVECDB_OFFS,
BHIE_TXVECDB_SEQNUM_BMSK, BHIE_TXVECDB_SEQNUM_SHFT,
sequence_id);
@@ -254,6 +257,9 @@ static int mhi_fw_load_sbl(struct mhi_controller *mhi_cntrl,
lower_32_bits(dma_addr));
mhi_write_reg(mhi_cntrl, base, BHI_IMGSIZE, size);
session_id = prandom_u32() & BHI_TXDB_SEQNUM_BMSK;
+ if (unlikely(!session_id))
+ session_id = 1;
+
mhi_write_reg(mhi_cntrl, base, BHI_IMGTXDB, session_id);
read_unlock_bh(pm_lock);