Re: [PATCH v7 07/19] clk: scmi: check the clock state/parent/rate control permissions

Lothar Waßmann
2025-03-06T05:12:00Z

Hi,

On Wed, 05 Mar 2025 21:28:19 +0800 Alice Guo (OSS) wrote:
> From: Alice Guo <alice.guo@nxp.com>
>
> Clock driver based on SCMI clock management protocol in Linux checks
> clock state, parent and rate control permissions. To be consistent with
> the kernel driver, add this check here.
>
> When using common clock framework (CCF), use the clock signal ID to get
> the clock registered by clk_register() in scmi_clk_probe(), and then
> obatin the struct clk_scmi variable with container_of().
>
> Signed-off-by: Alice Guo <alice.guo@nxp.com>
> Signed-off-by: Ye Li <ye.li@nxp.com>
> Reviewed-by: Peng Fan <peng.fan@nxp.com>
> ---
> drivers/clk/clk_scmi.c | 173 +++++++++++++++++++++++++++++++++++++++++++----
> include/scmi_protocols.h | 26 ++++++-
> 2 files changed, 186 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/clk/clk_scmi.c b/drivers/clk/clk_scmi.c
> index 84333cdd0c..d120c1eba0 100644
> --- a/drivers/clk/clk_scmi.c
> +++ b/drivers/clk/clk_scmi.c
> @@ -12,6 +12,56 @@
> #include <asm/types.h>
> #include <linux/clk-provider.h>
>
> +struct clk_scmi {
> + struct clk clk;
> + u32 ctrl_flags;
> +};
> +
> +static int scmi_clk_get_permissions(struct udevice *dev, int clkid, u32 *perm)
> +{
> + u32 version;
> + int ret;
> +
> + struct scmi_clk_get_permissions_in in = {
> + .clock_id = clkid,
> + };
> + struct scmi_clk_get_permissions_out out;
> + struct scmi_msg msg = {
> + .protocol_id = SCMI_PROTOCOL_ID_CLOCK,
> + .message_id = SCMI_CLOCK_GET_PERMISSIONS,
> + .in_msg = (u8 *)&in,
> + .in_msg_sz = sizeof(in),
> + .out_msg = (u8 *)&out,
> + .out_msg_sz = sizeof(out),
> + };
> +
> + ret = scmi_generic_protocol_version(dev, SCMI_PROTOCOL_ID_CLOCK, &version);
> + if (ret) {
> + log_debug("%s: get SCMI clock management protocol version failed\n", __func__);
> + return ret;
> + }
> +
> + if (version < CLOCK_PROTOCOL_VERSION_3_0) {
> + log_debug("%s: SCMI clock management protocol version is less than 3.0.\n", __func__);
> + return -EINVAL;
> + }
> +
> + ret = devm_scmi_process_msg(dev, &msg);
> + if (ret) {
> + log_debug("%s: get SCMI clock management protocol permissions failed\n", __func__);
> + return ret;
> + }
> +
> + ret = scmi_to_linux_errno(out.status);
> + if (ret < 0) {
> + log_debug("%s: the status code of getting permissions: %d\n", __func__, ret);
> + return ret;
> + }
> +
> + *perm = out.permissions;
> + return 0;
> +}
> +
> static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
> {
> struct scmi_clk_protocol_attr_out out;
> @@ -32,7 +82,8 @@ static int scmi_clk_get_num_clock(struct udevice *dev, size_t *num_clocks)
> return 0;
> }
>
> -static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
> +static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name,
> + u32 *attr)
> {
> struct scmi_clk_attribute_in in = {
> .clock_id = clkid,
> @@ -53,6 +104,7 @@ static int scmi_clk_get_attibute(struct udevice *dev, int clkid, char **name)
> return ret;
>
> *name = strdup(out.clock_name);
> + *attr = out.attributes;
>
> return 0;
> }
> @@ -78,12 +130,48 @@ static int scmi_clk_gate(struct clk *clk, int enable)
>
> static int scmi_clk_enable(struct clk *clk)
> {
> - return scmi_clk_gate(clk, 1);
> + struct clk_scmi *clkscmi;
> + struct clk *c;
> + int ret;
> +
> + if (!CONFIG_IS_ENABLED(CLK_CCF))
> + return scmi_clk_gate(clk, 1);
> +
> + ret = clk_get_by_id(clk->id, &c);
> + if (ret)
> + return ret;
> +
> + clkscmi = container_of(c, struct clk_scmi, clk);
> +
> + if (clkscmi->ctrl_flags & SUPPORT_CLK_STAT_CONTROL)
> + return scmi_clk_gate(clk, 1);
> +
> + /* Following Linux drivers/clk/clk-scmi.c, directly return 0 if agent has no permission. */
> + log_debug("%s: SCMI CLOCK: the clock cannot be enabled by the agent.\n", __func__);
> + return 0;
> }
>
> static int scmi_clk_disable(struct clk *clk)
> {
> - return scmi_clk_gate(clk, 0);
> + struct clk_scmi *clkscmi;
> + struct clk *c;
> + int ret;
> +
> + if (!CONFIG_IS_ENABLED(CLK_CCF))
> + return scmi_clk_gate(clk, 0);
> +
> + ret = clk_get_by_id(clk->id, &c);
> + if (ret)
> + return ret;
> +
> + clkscmi = container_of(c, struct clk_scmi, clk);
> +
> + if (clkscmi->ctrl_flags & SUPPORT_CLK_STAT_CONTROL)
> + return scmi_clk_gate(clk, 0);
> +
> + /* Following Linux drivers/clk/clk-scmi.c, directly return 0 if agent has no permission. */
> + log_debug("%s: SCMI CLOCK: the clock cannot be disabled by the agent.\n", __func__);
> + return 0;
> }
>
> static ulong scmi_clk_get_rate(struct clk *clk)
> @@ -108,7 +196,7 @@ static ulong scmi_clk_get_rate(struct clk *clk)
> return (ulong)(((u64)out.rate_msb << 32) | out.rate_lsb);
> }
>
> -static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
> +static ulong __scmi_clk_set_rate(struct clk *clk, ulong rate)
> {
> struct scmi_clk_rate_set_in in = {
> .clock_id = clk->id,
> @@ -133,9 +221,32 @@ static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
> return scmi_clk_get_rate(clk);
> }
>
> +static ulong scmi_clk_set_rate(struct clk *clk, ulong rate)
> +{
> + struct clk_scmi *clkscmi;
> + struct clk *c;
> + int ret;
> +
> + if (!CONFIG_IS_ENABLED(CLK_CCF))
> + return __scmi_clk_set_rate(clk, rate);
> +
> + ret = clk_get_by_id(clk->id, &c);
> + if (ret)
> + return ret;
> +
> + clkscmi = container_of(c, struct clk_scmi, clk);
> +
> + if (clkscmi->ctrl_flags & SUPPORT_CLK_RATE_CONTROL)
> + return __scmi_clk_set_rate(clk, rate);
> +
> + /* Following Linux drivers/clk/clk-scmi.c, directly return 0 if agent has no permission. */
> + log_debug("%s: SCMI CLOCK: the clock rate cannot be changed by the agent.\n", __func__);
> + return 0;
> +}
> +
> static int scmi_clk_probe(struct udevice *dev)
> {
> - struct clk *clk;
> + struct clk_scmi *clk_scmi;
> size_t num_clocks, i;
> int ret;
>
> @@ -156,29 +267,44 @@ static int scmi_clk_probe(struct udevice *dev)
>
> for (i = 0; i < num_clocks; i++) {
> char *clock_name;
> + u32 attributes;
>
> - if (!scmi_clk_get_attibute(dev, i, &clock_name)) {
> - clk = kzalloc(sizeof(*clk), GFP_KERNEL);
> - if (!clk || !clock_name)
> + if (!scmi_clk_get_attibute(dev, i, &clock_name, &attributes)) {
> + clk_scmi = kzalloc(sizeof(*clk_scmi), GFP_KERNEL);
> + if (!clk_scmi || !clock_name)
> ret = -ENOMEM;
> else
> - ret = clk_register(clk, dev->driver->name,
> + ret = clk_register(&clk_scmi->clk, dev->driver->name,
> clock_name, dev->name);
>
> if (ret) {
> - free(clk);
> + free(clk_scmi);
> free(clock_name);
> + free(&attributes);
> return ret;
> }
>
> - clk_dm(i, clk);
> + clk_dm(i, &clk_scmi->clk);
> +
> + if (CLK_HAS_RESTRICTIONS(attributes)) {
> + u32 perm;
> +
> + ret = scmi_clk_get_permissions(dev, i, &perm);
> + if (ret < 0)
> + clk_scmi->ctrl_flags = 0;
> + else
> + clk_scmi->ctrl_flags = perm;
> + } else {
> + clk_scmi->ctrl_flags = SUPPORT_CLK_STAT_CONTROL | SUPPORT_CLK_PARENT_CONTROL |
> + SUPPORT_CLK_RATE_CONTROL;
> + }
> }
> }
>
> return 0;
> }
>
> -static int scmi_clk_set_parent(struct clk *clk, struct clk *parent)
> +static int __scmi_clk_set_parent(struct clk *clk, struct clk *parent)
> {
> struct scmi_clk_parent_set_in in = {
> .clock_id = clk->id,
> @@ -197,6 +323,29 @@ static int scmi_clk_set_parent(struct clk *clk, struct clk *parent)
> return scmi_to_linux_errno(out.status);
> }
>
> +static int scmi_clk_set_parent(struct clk *clk, struct clk *parent)
> +{
> + struct clk_scmi *clkscmi;
> + struct clk *c;
> + int ret;
> +
> + if (!CONFIG_IS_ENABLED(CLK_CCF))
> + return -ENOTSUPP;
> +
> + ret = clk_get_by_id(clk->id, &c);
> + if (ret)
> + return ret;
> +
> + clkscmi = container_of(c, struct clk_scmi, clk);
> +
> + if (clkscmi->ctrl_flags & SUPPORT_CLK_PARENT_CONTROL)
> + return __scmi_clk_set_parent(clk, parent);
> +
> + /* Following Linux drivers/clk/clk-scmi.c, directly return 0 if agent has no permission. */
> + log_debug("%s: SCMI CLOCK: the clock's parent cannot be changed by the agent.\n", __func__);
> + return 0;
> +}
> +
> static const struct clk_ops scmi_clk_ops = {
> .enable = scmi_clk_enable,
> .disable = scmi_clk_disable,
> diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
> index 0d8c177025..2684f4177d 100644
> --- a/include/scmi_protocols.h
> +++ b/include/scmi_protocols.h
> @@ -731,13 +731,15 @@ int scmi_pwd_name_get(struct udevice *dev, u32 domain_id, u8 **name);
> /*
> * SCMI Clock Protocol
> */
> +#define CLOCK_PROTOCOL_VERSION_3_0 0x30000
>
> enum scmi_clock_message_id {
> SCMI_CLOCK_ATTRIBUTES = 0x3,
> SCMI_CLOCK_RATE_SET = 0x5,
> SCMI_CLOCK_RATE_GET = 0x6,
> SCMI_CLOCK_CONFIG_SET = 0x7,
> - SCMI_CLOCK_PARENT_SET = 0xD
> + SCMI_CLOCK_PARENT_SET = 0xD,
> + SCMI_CLOCK_GET_PERMISSIONS = 0xF
>
add a comma to facilitate extending the enum definition

Lothar Waßmann