Messages in this thread | | | Date | Tue, 31 Oct 2023 13:03:08 +0000 | From | Cristian Marussi <> | Subject | Re: [PATCH V1] firmware: arm_scmi: clock: support clock denied flags |
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On Tue, Oct 31, 2023 at 08:27:34PM +0800, Peng Fan (OSS) wrote: > From: Peng Fan <peng.fan@nxp.com> > > The firmware may export flags to indicate whether the clock > is allowed to set rate, set parent, enable/disable from the Agent. > > If Agent is not allowed to enable/disable, directly return success.
... even though, this success on deny built-in policy could be controversial...Have you tried the different approach of not registerig the enable/prepare callbacks in clk-scmi instead ? From the Clk framework code it seems could be handled gracefully. (I have not tried though...)
Thanks, Cristian
> If Agent is not allowed to set rate/parent, directly return -EACCES to > avoid SCMI RPC calls. > > Signed-off-by: Peng Fan <peng.fan@nxp.com> > --- > > V1: > drop the changes in clock.c, add an attribute entry in clock info which > may be easy for extending new flag. > > SPEC still not have such support, this is for discussion > > drivers/firmware/arm_scmi/clock.c | 19 +++++++++++++++++++ > include/linux/scmi_protocol.h | 1 + > 2 files changed, 20 insertions(+) > > diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c > index 42b81c181d68..fad4329a21fc 100644 > --- a/drivers/firmware/arm_scmi/clock.c > +++ b/drivers/firmware/arm_scmi/clock.c > @@ -46,6 +46,9 @@ 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 SCMI_CLOCK_SET_ENABLE_DENIED BIT(15) > +#define SCMI_CLOCK_SET_RATE_DENIED BIT(14) > +#define SCMI_CLOCK_SET_PARENT_DENIED BIT(13) > u8 name[SCMI_SHORT_NAME_MAX_SIZE]; > __le32 clock_enable_latency; > }; > @@ -307,6 +310,7 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph, > if (PROTOCOL_REV_MAJOR(version) >= 0x2) > latency = le32_to_cpu(attr->clock_enable_latency); > clk->enable_latency = latency ? : U32_MAX; > + clk->attributes = attributes; > } > > ph->xops->xfer_put(ph, t); > @@ -499,6 +503,10 @@ 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 = ci->clk + clk_id; > + > + if (clk->attributes & SCMI_CLOCK_SET_RATE_DENIED) > + return -EACCES; > > ret = ph->xops->xfer_get_init(ph, CLOCK_RATE_SET, sizeof(*cfg), 0, &t); > if (ret) > @@ -585,6 +593,9 @@ scmi_clock_set_parent(const struct scmi_protocol_handle *ph, u32 clk_id, > if (parent_id >= clk->num_parents) > return -EINVAL; > > + if (clk->attributes & SCMI_CLOCK_SET_PARENT_DENIED) > + return -EACCES; > + > ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_SET, > sizeof(*cfg), 0, &t); > if (ret) > @@ -668,6 +679,10 @@ 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 = ci->clk + clk_id; > + > + if (clk->attributes & SCMI_CLOCK_SET_ENABLE_DENIED) > + return 0; > > return ci->clock_config_set(ph, clk_id, CLK_STATE_ENABLE, > NULL_OEM_TYPE, 0, atomic); > @@ -677,6 +692,10 @@ 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 = ci->clk + clk_id; > + > + if (clk->attributes & SCMI_CLOCK_SET_ENABLE_DENIED) > + return 0; > > 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..ddf5363c8cfd 100644 > --- a/include/linux/scmi_protocol.h > +++ b/include/linux/scmi_protocol.h > @@ -58,6 +58,7 @@ struct scmi_clock_info { > u64 step_size; > } range; > }; > + u32 attributes; > int num_parents; > u32 *parents; > }; > -- > 2.37.1 >
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