On 10/4/26 21:22, Petr Hodina via B4 Relay wrote:
From: Petr Hodina <[email protected]>
Add CONFIG_UFS_RESTRICT_TX_LANES, to restrict the amount
PA_AVAILTXDATALANES = 1 at the start of ufshcd_link_startup().
Some platforms (notably the Sony Yoshino/Tama families on MSM8998 /
SDM845) have only a single reliably-usable UFS TX lane.
Why can't this be a quirk set only on those platforms ?
Neil>
Signed-off-by: Petr Hodina <[email protected]>
---
drivers/ufs/Kconfig | 14 ++++++++++++++
drivers/ufs/ufs-uclass.c | 13 +++++++++++++
2 files changed, 27 insertions(+)
diff --git a/drivers/ufs/Kconfig b/drivers/ufs/Kconfig
index 49472933de3..266e7180152 100644
--- a/drivers/ufs/Kconfig
+++ b/drivers/ufs/Kconfig
@@ -8,6 +8,20 @@ config UFS
This selects support for Universal Flash Subsystem (UFS).
Say Y here if you want UFS Support.
+config UFS_RESTRICT_TX_LANES
+ bool "Restrict the number of UFS TX lanes to 1"
+ depends on UFS
+ default n
+ help
+ Say Y here to restrict the number of UFS TX lanes to 1. This saves
+ power at the cost of write performance.
+
+ This is useful (and on some devices required) for platforms such as
+ the Sony Yoshino/Tama families where only a single TX lane is
+ reliably usable.
+
+ If unsure, say N.
+
config UFS_AMD_VERSAL2
bool "AMD Versal Gen 2 UFS controller platform driver"
depends on UFS && ZYNQMP_FIRMWARE
diff --git a/drivers/ufs/ufs-uclass.c b/drivers/ufs/ufs-uclass.c
index fdf62a69c02..977ffebc21f 100644
--- a/drivers/ufs/ufs-uclass.c
+++ b/drivers/ufs/ufs-uclass.c
@@ -508,6 +508,19 @@ static int ufshcd_link_startup(struct ufs_hba *hba)
int ret;
int retries = DME_LINKSTARTUP_RETRIES;
+ if (IS_ENABLED(CONFIG_UFS_RESTRICT_TX_LANES)) {
+ /*
+ * Restrict the number of available TX lanes to 1. This saves
+ * power at the cost of write performance and is required on
+ * some platforms (e.g. Sony Yoshino/Tama) where only a single
+ * TX lane is reliably usable.
+ */
+ ret = ufshcd_dme_set(hba, UIC_ARG_MIB(PA_AVAILTXDATALANES), 1);
+ if (ret)
+ dev_warn(hba->dev, "%s: failed to restrict TX lanes:
%d\n",
+ __func__, ret);
+ }
+
do {
ret = ufshcd_ops_link_startup_notify(hba, PRE_CHANGE);
if (ret)
