[PATCH 5.17 0023/1126] bus: mhi: Fix pm_state conversion to string

Greg Kroah-Hartman
2022-04-05T07:40:35Z

From: Paul Davey <paul.davey@alliedtelesis.co.nz>

commit 64f93a9a27c1970fa8ee5ffc5a6ae2bda477ec5b upstream.

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.

Fix by using __fls to pass the value of state instead of find_last_bit.

Also the current API expects "mhi_pm_state" enumerator as the function
argument but the function only works with bitmasks. So as Alex suggested,
let's change the argument to u32 to avoid confusion.

Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions")
Cc: stable@vger.kernel.org
[mani: changed the function argument to u32]
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220301160308.107452-3-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/bus/mhi/core/init.c | 10 ++++++----
drivers/bus/mhi/core/internal.h | 2 +-
2 files changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -77,12 +77,14 @@ static const char * const mhi_pm_state_s
[MHI_PM_STATE_LD_ERR_FATAL_DETECT] = "Linkdown or Error Fatal Detect",
};

-const char *to_mhi_pm_state_str(enum mhi_pm_state state)
+const char *to_mhi_pm_state_str(u32 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];
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -622,7 +622,7 @@ void mhi_free_bhie_table(struct mhi_cont
enum mhi_pm_state __must_check mhi_tryset_pm_state(
struct mhi_controller *mhi_cntrl,
enum mhi_pm_state state);
-const char *to_mhi_pm_state_str(enum mhi_pm_state state);
+const char *to_mhi_pm_state_str(u32 state);
int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
enum dev_st_transition state);
void mhi_pm_st_worker(struct work_struct *work);