[PATCH 2/3] scsi: ufs: core: allow host driver to enable wb buffer resize function

[PATCH 2/3] scsi: ufs: core: allow host driver to enable wb buffer resize function

[Lu Hongfei]

Since UFS4.1 will support the WB buffer resize function, the host could
choose to enable or disable it as needed.

Introduce a flag UFSHCD_CAP_WB_BUF_RESIZE to provide the host with the
ability to enable or disable WB buffer resize function.

UFSHCD_CAP_WB_BUF_RESIZE is only valid when UFSHCD_CAP_WB_EN is set.

Signed-off-by: Lu Hongfei <luhongfei@vivo.com>
---
 include/ufs/ufshcd.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 7d07b256e906..7ea226b69e79 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -720,6 +720,13 @@ enum ufshcd_caps {
 	 * WriteBooster when scaling the clock down.
 	 */
 	UFSHCD_CAP_WB_WITH_CLK_SCALING			= 1 << 12,
+
+	/*
+	 * This capability allows the host controller driver to
+	 * resize (increase or decrease) WriteBooster Buffer,
+	 * if the underlying device supports it and is provisioned to be used.
+	 */
+	UFSHCD_CAP_WB_BUF_RESIZE			= 1 << 13,
 };
 
 struct ufs_hba_variant_params {
@@ -1193,6 +1200,11 @@ static inline bool ufshcd_is_wb_allowed(struct ufs_hba *hba)
 	return hba->caps & UFSHCD_CAP_WB_EN;
 }
 
+static inline bool ufshcd_is_wb_buf_resize_allowed(struct ufs_hba *hba)
+{
+	return hba->caps & UFSHCD_CAP_WB_BUF_RESIZE;
+}
+
 static inline bool ufshcd_enable_wb_if_scaling_up(struct ufs_hba *hba)
 {
 	return hba->caps & UFSHCD_CAP_WB_WITH_CLK_SCALING;
-- 
2.39.0

Re: [PATCH 2/3] scsi: ufs: core: allow host driver to enable wb buffer resize function

[Bart Van Assche]

On 9/7/23 00:35, Lu Hongfei wrote:
> Since UFS4.1 will support the WB buffer resize function, the host could
> choose to enable or disable it as needed.
> 
> Introduce a flag UFSHCD_CAP_WB_BUF_RESIZE to provide the host with the
> ability to enable or disable WB buffer resize function.
> 
> UFSHCD_CAP_WB_BUF_RESIZE is only valid when UFSHCD_CAP_WB_EN is set.

Please drop this patch. It should be sufficient that WB buffer resizing
can be controlled via sysfs. I don't think that the host driver should
be able to decide whether or not this functionality is enabled.

Additionally, when reposting this patch series, please include a cover
letter such that e-mail clients that support threading group these
patches into a series.

Thanks,

Bart.