Messages in this thread | | | Date | Wed, 31 Mar 2021 10:09:51 -0700 | From | Bhaumik Bhatt <> | Subject | Re: [PATCH v5 1/2] bus: mhi: core: Introduce internal register poll helper function |
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Hi Mani,
On 2021-03-31 06:03 AM, Manivannan Sadhasivam wrote: > On Mon, Mar 29, 2021 at 12:53:02PM -0700, Bhaumik Bhatt wrote: >> Introduce helper function to allow MHI core driver to poll for >> a value in a register field. This helps reach a common path to >> read and poll register values along with a retry time interval. >> >> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> >> --- >> drivers/bus/mhi/core/internal.h | 3 +++ >> drivers/bus/mhi/core/main.c | 23 +++++++++++++++++++++++ >> 2 files changed, 26 insertions(+) >> >> diff --git a/drivers/bus/mhi/core/internal.h >> b/drivers/bus/mhi/core/internal.h >> index 6f80ec3..005286b 100644 >> --- a/drivers/bus/mhi/core/internal.h >> +++ b/drivers/bus/mhi/core/internal.h >> @@ -643,6 +643,9 @@ int __must_check mhi_read_reg(struct >> mhi_controller *mhi_cntrl, >> int __must_check mhi_read_reg_field(struct mhi_controller *mhi_cntrl, >> void __iomem *base, u32 offset, u32 mask, >> u32 shift, u32 *out); >> +int __must_check mhi_poll_reg_field(struct mhi_controller *mhi_cntrl, >> + void __iomem *base, u32 offset, u32 mask, >> + u32 shift, u32 val, u32 delayus); >> void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem >> *base, >> u32 offset, u32 val); >> void mhi_write_reg_field(struct mhi_controller *mhi_cntrl, void >> __iomem *base, >> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c >> index 4e0131b..6f4b630 100644 >> --- a/drivers/bus/mhi/core/main.c >> +++ b/drivers/bus/mhi/core/main.c >> @@ -4,6 +4,7 @@ >> * >> */ >> >> +#include <linux/delay.h> >> #include <linux/device.h> >> #include <linux/dma-direction.h> >> #include <linux/dma-mapping.h> >> @@ -37,6 +38,28 @@ int __must_check mhi_read_reg_field(struct >> mhi_controller *mhi_cntrl, >> return 0; >> } >> >> +int __must_check mhi_poll_reg_field(struct mhi_controller *mhi_cntrl, >> + void __iomem *base, u32 offset, >> + u32 mask, u32 shift, u32 val, u32 delayus) >> +{ >> + int ret; >> + u32 out, retry = (mhi_cntrl->timeout_ms * 1000) / delayus; >> + >> + while (retry--) { >> + ret = mhi_read_reg_field(mhi_cntrl, base, offset, mask, shift, >> + &out); >> + if (ret) >> + return ret; >> + >> + if (out == val) >> + return 0; >> + >> + fsleep(delayus); >> + } >> + >> + return -ENOENT; > > Maybe I'm too late on this one, but I don't think -ENOENT is the > correct > error code here. The error code will be returned only when the reg > field > value didn't change as expected, so in that case it should be -EINVAL > or > -ETIMEDOUT, no? > > Thanks, > Mani >
Thanks for pointing that out.
The intention of the error code was despite polling for whatever time period, we were unable to see the value changing as expected. I think the -ETIMEDOUT error code would be appropriate. Will upload a v6.
>> +} >> + >> void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem >> *base, >> u32 offset, u32 val) >> { >> -- >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora >> Forum, >> a Linux Foundation Collaborative Project >>
Thanks, Bhaumik --- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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