| Message ID | 20220212182117.49438-2-manivannan.sadhasivam@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,01/25] bus: mhi: Fix pm_state conversion to string | expand |
On 2/12/22 12:20 PM, Manivannan Sadhasivam wrote: > From: Paul Davey <paul.davey@alliedtelesis.co.nz> > > On big endian architectures the mhi debugfs files which report pm state > give "Invalid State" for all states. This is caused by using > find_last_bit which takes an unsigned long* while the state is passed in > as an enum mhi_pm_state which will be of int size. I think this would have fixed it too, but your fix is better. int index = find_last_bit(&(unsigned long)state, 32); > Fix by using __fls to pass the value of state instead of find_last_bit. > > Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions") > Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz> > Reviewed-by: Manivannan Sadhasivam <mani@kernel.org> > Reviewed-by: Hemant Kumar <hemantk@codeaurora.org> > Cc: stable@vger.kernel.org > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > --- > drivers/bus/mhi/core/init.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > index 046f407dc5d6..af484b03558a 100644 > --- a/drivers/bus/mhi/core/init.c > +++ b/drivers/bus/mhi/core/init.c > @@ -79,10 +79,12 @@ static const char * const mhi_pm_state_str[] = { > > const char *to_mhi_pm_state_str(enum mhi_pm_state state) The mhi_pm_state enumerated type is an enumerated sequence, not a bit mask. So knowing what the last (most significant) set bit is not meaningful. Or normally it shouldn't be. If mhi_pm_state really were a bit mask, then its values should be defined that way, i.e., MHI_PM_STATE_DISABLE = 1 << 0, MHI_PM_STATE_DISABLE = 1 << 1, . . . What's really going on is that the state value passed here *is* a bitmask, whose bit positions are those mhi_pm_state values. So the state argument should have type u32. This is a *separate* bug/issue. It could be fixed separately (before this patch), but I'd be OK with just explaining why this change would occur as part of this modified patch. > { > - unsigned long pm_state = state; > - int index = find_last_bit(&pm_state, 32); > + int index; > > - if (index >= ARRAY_SIZE(mhi_pm_state_str)) > + if (state) > + index = __fls(state); > + > + if (!state || index >= ARRAY_SIZE(mhi_pm_state_str)) > return "Invalid State"; Do this test and return first, and skip the additional check for "if (state)". -Alex > return mhi_pm_state_str[index];
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index 046f407dc5d6..af484b03558a 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -79,10 +79,12 @@ static const char * const mhi_pm_state_str[] = { const char *to_mhi_pm_state_str(enum mhi_pm_state state) { - unsigned long pm_state = state; - int index = find_last_bit(&pm_state, 32); + int index; - if (index >= ARRAY_SIZE(mhi_pm_state_str)) + if (state) + index = __fls(state); + + if (!state || index >= ARRAY_SIZE(mhi_pm_state_str)) return "Invalid State"; return mhi_pm_state_str[index];