firmware: arm_scmi: Add support for clock parents

SCMI v3.2 spec introduces CLOCK_POSSIBLE_PARENTS_GET, CLOCK_PARENT_SET
and CLOCK_PARENT_GET. Add support for these to enable clock parents
and use them in the clock driver.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20231004-scmi-clock-v3-v5-1-1b8a1435673e@nxp.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 9c0e33c1efabcacb53f2cff5e23b09cdb511055e..42b81c181d687a885455934344db0961c217e9cf 100644 (file)
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -22,6 +22,9 @@ enum scmi_clock_protocol_cmd {
        CLOCK_RATE_NOTIFY = 0x9,
        CLOCK_RATE_CHANGE_REQUESTED_NOTIFY = 0xA,
        CLOCK_CONFIG_GET = 0xB,
+       CLOCK_POSSIBLE_PARENTS_GET = 0xC,
+       CLOCK_PARENT_SET = 0xD,
+       CLOCK_PARENT_GET = 0xE,
 };
 
 enum clk_state {
@@ -42,10 +45,28 @@ struct scmi_msg_resp_clock_attributes {
 #define SUPPORTS_RATE_CHANGED_NOTIF(x)         ((x) & BIT(31))
 #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))
        u8 name[SCMI_SHORT_NAME_MAX_SIZE];
        __le32 clock_enable_latency;
 };
 
+struct scmi_msg_clock_possible_parents {
+       __le32 id;
+       __le32 skip_parents;
+};
+
+struct scmi_msg_resp_clock_possible_parents {
+       __le32 num_parent_flags;
+#define NUM_PARENTS_RETURNED(x)                ((x) & 0xff)
+#define NUM_PARENTS_REMAINING(x)       ((x) >> 24)
+       __le32 possible_parents[];
+};
+
+struct scmi_msg_clock_set_parent {
+       __le32 id;
+       __le32 parent_id;
+};
+
 struct scmi_msg_clock_config_set {
        __le32 id;
        __le32 attributes;
@@ -168,6 +189,98 @@ scmi_clock_protocol_attributes_get(const struct scmi_protocol_handle *ph,
        return ret;
 }
 
+struct scmi_clk_ipriv {
+       struct device *dev;
+       u32 clk_id;
+       struct scmi_clock_info *clk;
+};
+
+static void iter_clk_possible_parents_prepare_message(void *message, unsigned int desc_index,
+                                                     const void *priv)
+{
+       struct scmi_msg_clock_possible_parents *msg = message;
+       const struct scmi_clk_ipriv *p = priv;
+
+       msg->id = cpu_to_le32(p->clk_id);
+       /* Set the number of OPPs to be skipped/already read */
+       msg->skip_parents = cpu_to_le32(desc_index);
+}
+
+static int iter_clk_possible_parents_update_state(struct scmi_iterator_state *st,
+                                                 const void *response, void *priv)
+{
+       const struct scmi_msg_resp_clock_possible_parents *r = response;
+       struct scmi_clk_ipriv *p = priv;
+       struct device *dev = ((struct scmi_clk_ipriv *)p)->dev;
+       u32 flags;
+
+       flags = le32_to_cpu(r->num_parent_flags);
+       st->num_returned = NUM_PARENTS_RETURNED(flags);
+       st->num_remaining = NUM_PARENTS_REMAINING(flags);
+
+       /*
+        * num parents is not declared previously anywhere so we
+        * assume it's returned+remaining on first call.
+        */
+       if (!st->max_resources) {
+               p->clk->num_parents = st->num_returned + st->num_remaining;
+               p->clk->parents = devm_kcalloc(dev, p->clk->num_parents,
+                                              sizeof(*p->clk->parents),
+                                              GFP_KERNEL);
+               if (!p->clk->parents) {
+                       p->clk->num_parents = 0;
+                       return -ENOMEM;
+               }
+               st->max_resources = st->num_returned + st->num_remaining;
+       }
+
+       return 0;
+}
+
+static int iter_clk_possible_parents_process_response(const struct scmi_protocol_handle *ph,
+                                                     const void *response,
+                                                     struct scmi_iterator_state *st,
+                                                     void *priv)
+{
+       const struct scmi_msg_resp_clock_possible_parents *r = response;
+       struct scmi_clk_ipriv *p = priv;
+
+       u32 *parent = &p->clk->parents[st->desc_index + st->loop_idx];
+
+       *parent = le32_to_cpu(r->possible_parents[st->loop_idx]);
+
+       return 0;
+}
+
+static int scmi_clock_possible_parents(const struct scmi_protocol_handle *ph, u32 clk_id,
+                                      struct scmi_clock_info *clk)
+{
+       struct scmi_iterator_ops ops = {
+               .prepare_message = iter_clk_possible_parents_prepare_message,
+               .update_state = iter_clk_possible_parents_update_state,
+               .process_response = iter_clk_possible_parents_process_response,
+       };
+
+       struct scmi_clk_ipriv ppriv = {
+               .clk_id = clk_id,
+               .clk = clk,
+               .dev = ph->dev,
+       };
+       void *iter;
+       int ret;
+
+       iter = ph->hops->iter_response_init(ph, &ops, 0,
+                                           CLOCK_POSSIBLE_PARENTS_GET,
+                                           sizeof(struct scmi_msg_clock_possible_parents),
+                                           &ppriv);
+       if (IS_ERR(iter))
+               return PTR_ERR(iter);
+
+       ret = ph->hops->iter_response_run(iter);
+
+       return ret;
+}
+
 static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
                                     u32 clk_id, struct scmi_clock_info *clk,
                                     u32 version)
@@ -212,6 +325,8 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
                        clk->rate_changed_notifications = true;
                if (SUPPORTS_RATE_CHANGE_REQUESTED_NOTIF(attributes))
                        clk->rate_change_requested_notifications = true;
+               if (SUPPORTS_PARENT_CLOCK(attributes))
+                       scmi_clock_possible_parents(ph, clk_id, clk);
        }
 
        return ret;
@@ -229,12 +344,6 @@ static int rate_cmp_func(const void *_r1, const void *_r2)
                return 1;
 }
 
-struct scmi_clk_ipriv {
-       struct device *dev;
-       u32 clk_id;
-       struct scmi_clock_info *clk;
-};
-
 static void iter_clk_describe_prepare_message(void *message,
                                              const unsigned int desc_index,
                                              const void *priv)
@@ -458,6 +567,64 @@ scmi_clock_config_set(const struct scmi_protocol_handle *ph, u32 clk_id,
        return ret;
 }
 
+static int
+scmi_clock_set_parent(const struct scmi_protocol_handle *ph, u32 clk_id,
+                     u32 parent_id)
+{
+       int ret;
+       struct scmi_xfer *t;
+       struct scmi_msg_clock_set_parent *cfg;
+       struct clock_info *ci = ph->get_priv(ph);
+       struct scmi_clock_info *clk;
+
+       if (clk_id >= ci->num_clocks)
+               return -EINVAL;
+
+       clk = ci->clk + clk_id;
+
+       if (parent_id >= clk->num_parents)
+               return -EINVAL;
+
+       ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_SET,
+                                     sizeof(*cfg), 0, &t);
+       if (ret)
+               return ret;
+
+       t->hdr.poll_completion = false;
+
+       cfg = t->tx.buf;
+       cfg->id = cpu_to_le32(clk_id);
+       cfg->parent_id = cpu_to_le32(clk->parents[parent_id]);
+
+       ret = ph->xops->do_xfer(ph, t);
+
+       ph->xops->xfer_put(ph, t);
+
+       return ret;
+}
+
+static int
+scmi_clock_get_parent(const struct scmi_protocol_handle *ph, u32 clk_id,
+                     u32 *parent_id)
+{
+       int ret;
+       struct scmi_xfer *t;
+
+       ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_GET,
+                                     sizeof(__le32), sizeof(u32), &t);
+       if (ret)
+               return ret;
+
+       put_unaligned_le32(clk_id, t->tx.buf);
+
+       ret = ph->xops->do_xfer(ph, t);
+       if (!ret)
+               *parent_id = get_unaligned_le32(t->rx.buf);
+
+       ph->xops->xfer_put(ph, t);
+       return ret;
+}
+
 /* For SCMI clock v2.1 and onwards */
 static int
 scmi_clock_config_set_v2(const struct scmi_protocol_handle *ph, u32 clk_id,
@@ -650,6 +817,8 @@ static const struct scmi_clk_proto_ops clk_proto_ops = {
        .state_get = scmi_clock_state_get,
        .config_oem_get = scmi_clock_config_oem_get,
        .config_oem_set = scmi_clock_config_oem_set,
+       .parent_set = scmi_clock_set_parent,
+       .parent_get = scmi_clock_get_parent,
 };
 
 static int scmi_clk_rate_notify(const struct scmi_protocol_handle *ph,

diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 27bfa5a65b4507ea888fa6493315d8dcdba9687c..f2f05fb42d284034a94ba61d99e0e6d4fc523a1b 100644 (file)
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -58,6 +58,8 @@ struct scmi_clock_info {
                        u64 step_size;
                } range;
        };
+       int num_parents;
+       u32 *parents;
 };
 
 enum scmi_power_scale {
@@ -83,6 +85,8 @@ struct scmi_protocol_handle;
  * @state_get: get the status of the specified clock
  * @config_oem_get: get the value of an OEM specific clock config
  * @config_oem_set: set the value of an OEM specific clock config
+ * @parent_get: get the parent id of a clk
+ * @parent_set: set the parent of a clock
  */
 struct scmi_clk_proto_ops {
        int (*count_get)(const struct scmi_protocol_handle *ph);
@@ -104,6 +108,8 @@ struct scmi_clk_proto_ops {
                              bool atomic);
        int (*config_oem_set)(const struct scmi_protocol_handle *ph, u32 clk_id,
                              u8 oem_type, u32 oem_val, bool atomic);
+       int (*parent_get)(const struct scmi_protocol_handle *ph, u32 clk_id, u32 *parent_id);
+       int (*parent_set)(const struct scmi_protocol_handle *ph, u32 clk_id, u32 parent_id);
 };
 
 struct scmi_perf_domain_info {