Messages in this thread | | | Date | Fri, 01 May 2020 19:33:03 -0700 | From | bbhatt@codeauro ... | Subject | Re: [PATCH v3 9/9] bus: mhi: core: Ensure non-zero session or sequence ID values |
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On 2020-04-30 08:12, Jeffrey Hugo wrote: > On 4/29/2020 2:52 PM, Bhaumik Bhatt wrote: >> 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> >> --- >> 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; > > Seems like you could use prandom_u32_max(), and add 1 to the result to > eliminate the conditional. What do you think? >
Agreed. Done using an internal macro in those places.
>> + >> 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); >>
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