On 2/23/2021 8:44 PM, 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@xxxxxxxxxxxxxx>
---
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..249ae26 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 = -ENOENT;
+ 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 -EIO;
I generally dislike recoding return codes. Do you believe it adds value
here? I'm concerned that if I'm debugging an error, I'll get EIO, which
I trace to here, but then I don't know what the actual error from
mhi_read_reg_field() was.
+
+ if (out == val)
+ return 0;
+
+ udelay(delayus);
+ }
+
+ return ret;
+}
+
void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem *base,
u32 offset, u32 val)
{
--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
