firmware: arm_scmi: Keep the discrete clock rates sorted

Instead of relying on the firmware to keep the clock rates sorted, let
us sort the list. This is not essential for clock layer but it helps
to find the min and max rates easily from the list.

Link: https://lore.kernel.org/r/20200709081705.46084-1-sudeep.holla@arm.com
Fixes: 5f6c6430 ("firmware: arm_scmi: add initial support for clock protocol")
Reported-and-tested-by: Dien Pham <dien.pham.ry@renesas.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/clock.c

@@ -5,6 +5,8 @@
  * Copyright (C) 2018 ARM Ltd.
  */
 
+#include <linux/sort.h>
+
 #include "common.h"
 
 enum scmi_clock_protocol_cmd {
@@ -121,11 +123,23 @@ static int scmi_clock_attributes_get(const struct scmi_handle *handle,
 	return ret;
 }
 
+static int rate_cmp_func(const void *_r1, const void *_r2)
+{
+	const u64 *r1 = _r1, *r2 = _r2;
+
+	if (*r1 < *r2)
+		return -1;
+	else if (*r1 == *r2)
+		return 0;
+	else
+		return 1;
+}
+
 static int
 scmi_clock_describe_rates_get(const struct scmi_handle *handle, u32 clk_id,
 			      struct scmi_clock_info *clk)
 {
-	u64 *rate;
+	u64 *rate = 0;
 	int ret, cnt;
 	bool rate_discrete = false;
 	u32 tot_rate_cnt = 0, rates_flag;
@@ -184,8 +198,10 @@ scmi_clock_describe_rates_get(const struct scmi_handle *handle, u32 clk_id,
 		 */
 	} while (num_returned && num_remaining);
 
-	if (rate_discrete)
+	if (rate_discrete && rate) {
 		clk->list.num_rates = tot_rate_cnt;
+		sort(rate, tot_rate_cnt, sizeof(*rate), rate_cmp_func, NULL);
+	}
 
 	clk->rate_discrete = rate_discrete;