clk: qcom: clk-cpu-osm: Allow overriding CPU frequency tables in DT

Sometimes, it may be desirable to use CPU frequency tables different
from the ones in the hardware's OSM LUTs. This commit adds support for
overriding each CPU's frequency table with a list of allowed frequencies
defined in the OSM driver's DT node.

Signed-off-by: Danny Lin <danny@kdrag0n.dev>

Author: kdrag0n

Documentation/devicetree/bindings/arm/msm/qcom,osm.txt

@@ -58,6 +58,13 @@ Properties:
 	Value type: <phandle>
 	Definition: Phandle to the aux clock device.
 
+- qcom,cpufreq-table-XX
+	Usage: optional
+	Value type: <u32>
+	Definition: List of frequencies (in kHz) to expose in CPU XX's cpufreq table.
+		    All frequencies present in hardware will be exposed if this list
+		    is not present.
+
 Example:
 	clock_cpucc: qcom,cpucc@0x17d41000 {
 		compatible = "qcom,clk-cpu-osm";
@@ -74,4 +81,49 @@ Example:
 		clock-names = "xo_ao";
 		clocks = <&clock_rpmh RPMH_CXO_CLK_A>;
 		#clock-cells = <1>;
+		qcom,cpufreq-table-0 =
+			< 300000>,
+			< 403200>,
+			< 480000>,
+			< 576000>,
+			< 652800>,
+			< 748800>,
+			< 825600>,
+			< 902400>,
+			< 979200>,
+			<1056000>,
+			<1132800>,
+			<1228800>,
+			<1324800>,
+			<1420800>,
+			<1516800>,
+			<1612800>,
+			<1689600>,
+			<1766400>;
+
+		qcom,cpufreq-table-4 =
+			< 825600>,
+			< 902400>,
+			< 979200>,
+			<1056000>,
+			<1209600>,
+			<1286400>,
+			<1363200>,
+			<1459200>,
+			<1536000>,
+			<1612800>,
+			<1689600>,
+			<1766400>,
+			<1843200>,
+			<1920000>,
+			<1996800>,
+			<2092800>,
+			<2169600>,
+			<2246400>,
+			<2323200>,
+			<2400000>,
+			<2476800>,
+			<2553600>,
+			<2649600>,
+			<2803200>;
 	};

drivers/clk/qcom/clk-cpu-osm.c

@@ -80,6 +80,7 @@ struct osm_entry {
 };
 
 struct clk_osm {
+	struct device *dev;
 	struct clk_hw hw;
 	struct osm_entry osm_table[OSM_TABLE_SIZE];
 	struct dentry *debugfs;
@@ -90,6 +91,7 @@ struct clk_osm {
 	u32 num_entries;
 	u32 cluster_num;
 	u32 core_num;
+	u32 osm_table_size;
 	unsigned long rate;
 	u64 total_cycle_counter;
 	u32 prev_cycle_counter;
@@ -386,6 +388,7 @@ static struct clk_init_data osm_clks_init[] = {
 static struct clk_osm l3_clk = {
 	.cluster_num = 0,
 	.max_core_count = 4,
+	.osm_table_size = OSM_TABLE_SIZE,
 	.hw.init = &osm_clks_init[0],
 };
 
@@ -397,6 +400,7 @@ static DEFINE_CLK_VOTER(l3_gpu_vote_clk, l3_clk, 0);
 static struct clk_osm pwrcl_clk = {
 	.cluster_num = 1,
 	.max_core_count = 4,
+	.osm_table_size = OSM_TABLE_SIZE,
 	.hw.init = &osm_clks_init[1],
 };
 
@@ -481,6 +485,7 @@ static struct clk_osm cpu5_pwrcl_clk = {
 static struct clk_osm perfcl_clk = {
 	.cluster_num = 2,
 	.max_core_count = 4,
+	.osm_table_size = OSM_TABLE_SIZE,
 	.hw.init = &osm_clks_init[2],
 };
 
@@ -717,14 +722,31 @@ static unsigned int osm_cpufreq_get(unsigned int cpu)
 		return XO_RATE * curr_lval / 1000;
 }
 
+static bool osm_dt_find_freq(u32 *of_table, int of_len, long frequency)
+{
+	int i;
+
+	if (!of_table)
+		return true;
+
+	for (i = 0; i < of_len; i++) {
+		if (frequency == of_table[i])
+			return true;
+	}
+
+	return false;
+}
+
 static int osm_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	struct cpufreq_frequency_table *table;
 	struct clk_osm *c, *parent;
 	struct clk_hw *p_hw;
-	int ret;
+	int ret, of_len;
 	unsigned int i, prev_cc = 0;
 	unsigned int xo_kHz;
+	u32 *of_table = NULL;
+	char tbl_name[] = "qcom,cpufreq-table-##";
 
 	c = osm_configure_policy(policy);
 	if (!c) {
@@ -748,11 +770,33 @@ static int osm_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	}
 	xo_kHz = clk_hw_get_rate(p_hw) / 1000;
 
-	table = kcalloc(OSM_TABLE_SIZE + 1, sizeof(*table), GFP_KERNEL);
+	table = kcalloc(parent->osm_table_size + 1, sizeof(*table), GFP_KERNEL);
+
+	snprintf(tbl_name, sizeof(tbl_name), "qcom,cpufreq-table-%d", policy->cpu);
+	if (of_find_property(parent->dev->of_node, tbl_name, &of_len) && of_len > 0) {
+		of_len /= sizeof(*of_table);
+
+		of_table = kcalloc(of_len, sizeof(*of_table), GFP_KERNEL);
+		if (!of_table) {
+			pr_err("failed to allocate DT frequency table memory for CPU%d\n",
+			       policy->cpu);
+			return -ENOMEM;
+		}
+
+		ret = of_property_read_u32_array(parent->dev->of_node, tbl_name,
+						 of_table, of_len);
+		if (ret) {
+			pr_err("failed to read DT frequency table for CPU%d, err=%d\n",
+			       policy->cpu, ret);
+			return ret;
+		}
+	}
+
+	table = kcalloc(parent->osm_table_size + 1, sizeof(*table), GFP_KERNEL);
 	if (!table)
 		return -ENOMEM;
 
-	for (i = 0; i < OSM_TABLE_SIZE; i++) {
+	for (i = 0; i < parent->osm_table_size; i++) {
 		u32 data, src, div, lval, core_count;
 
 		data = clk_osm_read_reg(c, FREQ_REG + i * OSM_REG_SIZE);
@@ -767,6 +811,10 @@ static int osm_cpufreq_cpu_init(struct cpufreq_policy *policy)
 			table[i].frequency = xo_kHz * lval;
 		table[i].driver_data = table[i].frequency;
 
+		/* Ignore frequency if not present in DT table */
+		if (!osm_dt_find_freq(of_table, of_len, table[i].frequency))
+			table[i].frequency = CPUFREQ_ENTRY_INVALID;
+
 		if (core_count != parent->max_core_count)
 			table[i].frequency = CPUFREQ_ENTRY_INVALID;
 
@@ -795,9 +843,12 @@ static int osm_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 	policy->cpuinfo.transition_latency = MIN_RATE_LIMIT_US;
 	policy->driver_data = c;
+
+	kfree(of_table);
 	return 0;
 
 err:
+	kfree(of_table);
 	kfree(table);
 	return ret;
 }
@@ -1019,10 +1070,11 @@ static u64 clk_osm_get_cpu_cycle_counter(int cpu)
 
 static int clk_osm_read_lut(struct platform_device *pdev, struct clk_osm *c)
 {
-	u32 data, src, lval, i, j = OSM_TABLE_SIZE;
+	u32 data, src, lval, i, j = c->osm_table_size;
 	struct clk_vdd_class *vdd = osm_clks_init[c->cluster_num].vdd_class;
 
-	for (i = 0; i < OSM_TABLE_SIZE; i++) {
+	c->dev = &pdev->dev;
+	for (i = 0; i < c->osm_table_size; i++) {
 		data = clk_osm_read_reg(c, FREQ_REG + i * OSM_REG_SIZE);
 		src = ((data & GENMASK(31, 30)) >> 30);
 		lval = (data & GENMASK(7, 0));
@@ -1044,7 +1096,7 @@ static int clk_osm_read_lut(struct platform_device *pdev, struct clk_osm *c)
 			 c->osm_table[i].virtual_corner,
 			 c->osm_table[i].open_loop_volt);
 
-		if (i > 0 && j == OSM_TABLE_SIZE &&
+		if (i > 0 && j == c->osm_table_size &&
 				c->osm_table[i].frequency ==
 					c->osm_table[i - 1].frequency &&
 			c->osm_table[i].ccount == c->osm_table[i - 1].ccount)