Registers used by vendors to control any functionality could be
implemented by making the register secured. In such cases the
register cannot be updated with a new value since the normal
write ops will fail.
Hence, use the scm_call to do a secure write to the register.
Signed-off-by: Hiren Gohel <[email protected]>
---
drivers/firmware/qcom_scm.c | 19 +++++++++++++++++++
drivers/firmware/qcom_scm.h | 1 +
include/linux/qcom_scm.h | 2 ++
3 files changed, 22 insertions(+)
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index cdbfe54..7131df8 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -400,6 +400,25 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
}
EXPORT_SYMBOL(qcom_scm_set_remote_state);
+void qcom_scm_phy_update_scm_level_shifter(u32 val)
+{
+ int ret;
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_BOOT,
+ .cmd = QCOM_SCM_QUSB2PHY_LVL_SHIFTER_CMD_ID,
+ .owner = ARM_SMCCC_OWNER_SIP
+ };
+
+ desc.args[0] = val;
+ desc.args[1] = 0;
+ desc.arginfo = QCOM_SCM_ARGS(2);
+
+ ret = qcom_scm_call(__scm->dev, &desc, NULL);
+ if (ret)
+ pr_err("Failed to update scm level shifter=0x%x\n", ret);
+}
+EXPORT_SYMBOL(qcom_scm_phy_update_scm_level_shifter);
+
static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
{
struct qcom_scm_desc desc = {
diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
index 0d51eef..0a8c25b 100644
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -81,6 +81,7 @@ extern int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
#define QCOM_SCM_BOOT_SET_ADDR_MC 0x11
#define QCOM_SCM_BOOT_SET_REMOTE_STATE 0x0a
#define QCOM_SCM_FLUSH_FLAG_MASK 0x3
+#define QCOM_SCM_QUSB2PHY_LVL_SHIFTER_CMD_ID 0x1B
#define QCOM_SCM_BOOT_MAX_CPUS 4
#define QCOM_SCM_BOOT_MC_FLAG_AARCH64 BIT(0)
#define QCOM_SCM_BOOT_MC_FLAG_COLDBOOT BIT(1)
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index f8335644..3e5cbe9 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -124,4 +124,6 @@ extern int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
extern int qcom_scm_lmh_profile_change(u32 profile_id);
extern bool qcom_scm_lmh_dcvsh_available(void);
+extern void qcom_scm_phy_update_scm_level_shifter(u32 val);
+
#endif
--
2.7.4
On Thu, Sep 15, 2022 at 07:17:07PM +0530, Hiren Gohel wrote:
> Registers used by vendors to control any functionality could be
> implemented by making the register secured. In such cases the
> register cannot be updated with a new value since the normal
> write ops will fail.
>
> Hence, use the scm_call to do a secure write to the register.
>
This looks reasonable, but we need a caller of this API in order to
merge this patch.
> Signed-off-by: Hiren Gohel <[email protected]>
> ---
> drivers/firmware/qcom_scm.c | 19 +++++++++++++++++++
> drivers/firmware/qcom_scm.h | 1 +
> include/linux/qcom_scm.h | 2 ++
> 3 files changed, 22 insertions(+)
>
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index cdbfe54..7131df8 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -400,6 +400,25 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
> }
> EXPORT_SYMBOL(qcom_scm_set_remote_state);
>
> +void qcom_scm_phy_update_scm_level_shifter(u32 val)
That second "scm" doesn't seem necessary.
> +{
> + int ret;
> + struct qcom_scm_desc desc = {
> + .svc = QCOM_SCM_SVC_BOOT,
> + .cmd = QCOM_SCM_QUSB2PHY_LVL_SHIFTER_CMD_ID,
> + .owner = ARM_SMCCC_OWNER_SIP
> + };
> +
> + desc.args[0] = val;
> + desc.args[1] = 0;
> + desc.arginfo = QCOM_SCM_ARGS(2);
> +
> + ret = qcom_scm_call(__scm->dev, &desc, NULL);
Would it not make sense to return this error to the caller?
Regards,
Bjorn
> + if (ret)
> + pr_err("Failed to update scm level shifter=0x%x\n", ret);
> +}
> +EXPORT_SYMBOL(qcom_scm_phy_update_scm_level_shifter);
> +
> static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
> {
> struct qcom_scm_desc desc = {
> diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
> index 0d51eef..0a8c25b 100644
> --- a/drivers/firmware/qcom_scm.h
> +++ b/drivers/firmware/qcom_scm.h
> @@ -81,6 +81,7 @@ extern int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
> #define QCOM_SCM_BOOT_SET_ADDR_MC 0x11
> #define QCOM_SCM_BOOT_SET_REMOTE_STATE 0x0a
> #define QCOM_SCM_FLUSH_FLAG_MASK 0x3
> +#define QCOM_SCM_QUSB2PHY_LVL_SHIFTER_CMD_ID 0x1B
> #define QCOM_SCM_BOOT_MAX_CPUS 4
> #define QCOM_SCM_BOOT_MC_FLAG_AARCH64 BIT(0)
> #define QCOM_SCM_BOOT_MC_FLAG_COLDBOOT BIT(1)
> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
> index f8335644..3e5cbe9 100644
> --- a/include/linux/qcom_scm.h
> +++ b/include/linux/qcom_scm.h
> @@ -124,4 +124,6 @@ extern int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
> extern int qcom_scm_lmh_profile_change(u32 profile_id);
> extern bool qcom_scm_lmh_dcvsh_available(void);
>
> +extern void qcom_scm_phy_update_scm_level_shifter(u32 val);
> +
> #endif
> --
> 2.7.4
>