[PATCH V3 1/2] firmware: arm_scmi: Implement Clock get permissions

Peng Fan (OSS)
2024-01-15T05:57:53Z

From: Peng Fan <peng.fan@nxp.com>

ARM SCMI Spec 3.2 introduces Clock Get Permission command. This patch
is to add the support. Add three bool entries to scmi_clock_info to
indicate the operation is forbidden or not. If the CLOCK_GET_PERMISSIONS
command is not supported, the three bool variables will default
set to false, otherwise they will be set according to the return result
of CLOCK_GET_PERMISSIONS.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V3:
Rebased on https://lore.kernel.org/linux-arm-kernel/20240110120916.2482603-1-cristian.marussi@arm.com/
Drop attribute which is no needed
Use scmi_clock_domain_lookup
Update patch subject

V2:
Take Cristian's suggestion, https://lore.kernel.org/all/ZWiqqfQ73tezFmSk@pluto/

drivers/firmware/arm_scmi/clock.c | 64 +++++++++++++++++++++++++++++++
include/linux/scmi_protocol.h | 3 ++
2 files changed, 67 insertions(+)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 2e4d6479a639..959e48aba1b5 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -28,8 +28,13 @@ enum scmi_clock_protocol_cmd {
CLOCK_POSSIBLE_PARENTS_GET = 0xC,
CLOCK_PARENT_SET = 0xD,
CLOCK_PARENT_GET = 0xE,
+ CLOCK_GET_PERMISSIONS = 0xF,
};

+#define CLOCK_STATE_CONTROL_ALLOWED BIT(31)
+#define CLOCK_PARENT_CONTROL_ALLOWED BIT(30)
+#define CLOCK_RATE_CONTROL_ALLOWED BIT(29)
+
enum clk_state {
CLK_STATE_DISABLE,
CLK_STATE_ENABLE,
@@ -49,6 +54,7 @@ struct scmi_msg_resp_clock_attributes {
#define SUPPORTS_RATE_CHANGE_REQUESTED_NOTIF(x) ((x) & BIT(30))
#define SUPPORTS_EXTENDED_NAMES(x) ((x) & BIT(29))
#define SUPPORTS_PARENT_CLOCK(x) ((x) & BIT(28))
+#define SUPPORTS_GET_PERMISSIONS(x) ((x) & BIT(1))
u8 name[SCMI_SHORT_NAME_MAX_SIZE];
__le32 clock_enable_latency;
};
@@ -293,6 +299,35 @@ static int scmi_clock_possible_parents(const struct scmi_protocol_handle *ph, u3
return ret;
}

+static int
+scmi_clock_get_permissions(const struct scmi_protocol_handle *ph, u32 clk_id,
+ struct scmi_clock_info *clk)
+{
+ struct scmi_xfer *t;
+ u32 perm;
+ int ret;
+
+ ret = ph->xops->xfer_get_init(ph, CLOCK_GET_PERMISSIONS,
+ sizeof(clk_id), sizeof(perm), &t);
+ if (ret)
+ return ret;
+
+ put_unaligned_le32(clk_id, t->tx.buf);
+
+ ret = ph->xops->do_xfer(ph, t);
+ if (!ret) {
+ perm = get_unaligned_le32(t->rx.buf);
+
+ clk->state_ctrl_forbidden = !(perm & CLOCK_STATE_CONTROL_ALLOWED);
+ clk->rate_ctrl_forbidden = !(perm & CLOCK_RATE_CONTROL_ALLOWED);
+ clk->parent_ctrl_forbidden = !(perm & CLOCK_PARENT_CONTROL_ALLOWED);
+ }
+
+ ph->xops->xfer_put(ph, t);
+
+ return ret;
+}
+
static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
u32 clk_id, struct scmi_clock_info *clk,
u32 version)
@@ -339,6 +374,8 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
clk->rate_change_requested_notifications = true;
if (SUPPORTS_PARENT_CLOCK(attributes))
scmi_clock_possible_parents(ph, clk_id, clk);
+ if (SUPPORTS_GET_PERMISSIONS(attributes))
+ scmi_clock_get_permissions(ph, clk_id, clk);
}

return ret;
@@ -511,6 +548,14 @@ static int scmi_clock_rate_set(const struct scmi_protocol_handle *ph,
struct scmi_xfer *t;
struct scmi_clock_set_rate *cfg;
struct clock_info *ci = ph->get_priv(ph);
+ struct scmi_clock_info *clk;
+
+ clk = scmi_clock_domain_lookup(ci, clk_id);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ if (clk->rate_ctrl_forbidden)
+ return -EACCES;

ret = ph->xops->xfer_get_init(ph, CLOCK_RATE_SET, sizeof(*cfg), 0, &t);
if (ret)
@@ -596,6 +641,9 @@ scmi_clock_set_parent(const struct scmi_protocol_handle *ph, u32 clk_id,
if (parent_id >= clk->num_parents)
return -EINVAL;

+ if (clk->parent_ctrl_forbidden)
+ return -EACCES;
+
ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_SET,
sizeof(*cfg), 0, &t);
if (ret)
@@ -679,6 +727,14 @@ static int scmi_clock_enable(const struct scmi_protocol_handle *ph, u32 clk_id,
bool atomic)
{
struct clock_info *ci = ph->get_priv(ph);
+ struct scmi_clock_info *clk;
+
+ clk = scmi_clock_domain_lookup(ci, clk_id);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ if (clk->state_ctrl_forbidden)
+ return -EACCES;

return ci->clock_config_set(ph, clk_id, CLK_STATE_ENABLE,
NULL_OEM_TYPE, 0, atomic);
@@ -688,6 +744,14 @@ static int scmi_clock_disable(const struct scmi_protocol_handle *ph, u32 clk_id,
bool atomic)
{
struct clock_info *ci = ph->get_priv(ph);
+ struct scmi_clock_info *clk;
+
+ clk = scmi_clock_domain_lookup(ci, clk_id);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ if (clk->state_ctrl_forbidden)
+ return -EACCES;

return ci->clock_config_set(ph, clk_id, CLK_STATE_DISABLE,
NULL_OEM_TYPE, 0, atomic);
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index f2f05fb42d28..0cc40af5519a 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -47,6 +47,9 @@ struct scmi_clock_info {
bool rate_discrete;
bool rate_changed_notifications;
bool rate_change_requested_notifications;
+ bool state_ctrl_forbidden;
+ bool rate_ctrl_forbidden;
+ bool parent_ctrl_forbidden;
union {
struct {
int num_rates;
--
2.37.1