[PATCH v4 07/15] firmware: arm_scmi: Make clock rates allocation dynamic

Leveraging SCMI Clock protocol dynamic discovery capabilities, move away
from the static per-clock rates allocation model in favour of a dynamic
runtime allocation based on effectively discovered resources.

No functional change.

Reviewed-by: Peng Fan <[email protected]>
Signed-off-by: Cristian Marussi <[email protected]>
---
v2 --> v3
 - collected Review-by tags
---
 drivers/firmware/arm_scmi/clock.c | 19 ++++++++++++++++---
 include/linux/scmi_protocol.h     |  1 -
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 467b13a3a18f..c9b62edce4fd 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -161,7 +161,7 @@ struct scmi_clock_desc {
 	u32 id;
 	bool rate_discrete;
 	unsigned int num_rates;
-	u64 rates[SCMI_MAX_NUM_RATES];
+	u64 *rates;
 #define	RATE_MIN	0
 #define	RATE_MAX	1
 #define	RATE_STEP	2
@@ -480,6 +480,18 @@ iter_clk_describe_update_state(struct scmi_iterator_state *st,
 			   QUIRK_OUT_OF_SPEC_TRIPLET);
 	}
 
+	if (!st->max_resources) {
+		int num_rates = st->num_returned + st->num_remaining;
+
+		p->clkd->rates = devm_kcalloc(p->dev, num_rates,
+					      sizeof(*p->clkd->rates), GFP_KERNEL);
+		if (!p->clkd->rates)
+			return -ENOMEM;
+
+		/* max_resources is used by the iterators to control bounds */
+		st->max_resources = st->num_returned + st->num_remaining;
+	}
+
 	return 0;
 }
 
@@ -493,6 +505,8 @@ iter_clk_describe_process_response(const struct scmi_protocol_handle *ph,
 
 	p->clkd->rates[st->desc_index + st->loop_idx] =
 		RATE_TO_U64(r->rate[st->loop_idx]);
+
+	/* Count only effectively discovered rates */
 	p->clkd->num_rates++;
 
 	return 0;
@@ -515,8 +529,7 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id,
 		.dev = ph->dev,
 	};
 
-	iter = ph->hops->iter_response_init(ph, &ops, SCMI_MAX_NUM_RATES,
-					    CLOCK_DESCRIBE_RATES,
+	iter = ph->hops->iter_response_init(ph, &ops, 0, CLOCK_DESCRIBE_RATES,
 					    sizeof(struct scmi_msg_clock_describe_rates),
 					    &cpriv);
 	if (IS_ERR(iter))
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 19834f85f5d3..0824a7dc4aae 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -15,7 +15,6 @@
 
 #define SCMI_MAX_STR_SIZE		64
 #define SCMI_SHORT_NAME_MAX_SIZE	16
-#define SCMI_MAX_NUM_RATES		16
 
 /**
  * struct scmi_revision_info - version information structure
-- 
2.53.0