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Subject[PATCH v2 2/5] clk: mvebu: add CPU clock driver for Armada 7K/8K
Date
The CPU frequency is managed at the AP level for the Armada 7K/8K. The
CPU frequency is modified by cluster: the CPUs of the same cluster have
the same frequency.

This patch adds the clock driver that will be used by CPUFreq, it is
based on the work of Omri Itach <omrii@marvell.com>.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
drivers/clk/mvebu/Kconfig | 3 +
drivers/clk/mvebu/Makefile | 1 +
drivers/clk/mvebu/ap-cpu-clk.c | 259 +++++++++++++++++++++++++++++++++
3 files changed, 263 insertions(+)
create mode 100644 drivers/clk/mvebu/ap-cpu-clk.c

diff --git a/drivers/clk/mvebu/Kconfig b/drivers/clk/mvebu/Kconfig
index 5492fae3f0ab..9d0b2f7cee21 100644
--- a/drivers/clk/mvebu/Kconfig
+++ b/drivers/clk/mvebu/Kconfig
@@ -39,6 +39,9 @@ config ARMADA_AP806_SYSCON
bool
select ARMADA_AP_CP_HELPER

+config ARMADA_AP_CPU_CLK
+ bool
+
config ARMADA_CP110_SYSCON
bool
select ARMADA_AP_CP_HELPER
diff --git a/drivers/clk/mvebu/Makefile b/drivers/clk/mvebu/Makefile
index 6638ad962ec1..04464cef0f06 100644
--- a/drivers/clk/mvebu/Makefile
+++ b/drivers/clk/mvebu/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_ARMADA_37XX_CLK) += armada-37xx-tbg.o
obj-$(CONFIG_ARMADA_37XX_CLK) += armada-37xx-periph.o
obj-$(CONFIG_ARMADA_XP_CLK) += armada-xp.o mv98dx3236.o
obj-$(CONFIG_ARMADA_AP806_SYSCON) += ap806-system-controller.o
+obj-$(CONFIG_ARMADA_AP_CPU_CLK) += ap-cpu-clk.o
obj-$(CONFIG_ARMADA_CP110_SYSCON) += cp110-system-controller.o
obj-$(CONFIG_DOVE_CLK) += dove.o dove-divider.o
obj-$(CONFIG_KIRKWOOD_CLK) += kirkwood.o
diff --git a/drivers/clk/mvebu/ap-cpu-clk.c b/drivers/clk/mvebu/ap-cpu-clk.c
new file mode 100644
index 000000000000..e4cecb456884
--- /dev/null
+++ b/drivers/clk/mvebu/ap-cpu-clk.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Marvell Armada AP CPU Clock Controller
+ *
+ * Copyright (C) 2018 Marvell
+ *
+ * Omri Itach <omrii@marvell.com>
+ * Gregory Clement <gregory.clement@bootlin.com>
+ */
+
+#define pr_fmt(fmt) "ap-cpu-clk: " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include "armada_ap_cp_helper.h"
+
+#define AP806_CPU_CLUSTER0 0
+#define AP806_CPU_CLUSTER1 1
+#define AP806_CPUS_PER_CLUSTER 2
+#define APN806_CPU1_MASK 0x1
+
+#define APN806_CLUSTER_NUM_OFFSET 8
+#define APN806_CLUSTER_NUM_MASK BIT(APN806_CLUSTER_NUM_OFFSET)
+
+#define APN806_MAX_DIVIDER 32
+
+/* AP806 CPU DFS register mapping*/
+#define AP806_CA72MP2_0_PLL_CR_0_REG_OFFSET 0x278
+#define AP806_CA72MP2_0_PLL_CR_1_REG_OFFSET 0x280
+#define AP806_CA72MP2_0_PLL_CR_2_REG_OFFSET 0x284
+#define AP806_CA72MP2_0_PLL_SR_REG_OFFSET 0xC94
+
+#define AP806_CA72MP2_0_PLL_CR_CLUSTER_OFFSET 0x14
+#define AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_OFFSET 0
+#define AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_MASK \
+ (0x3f << AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_OFFSET)
+#define AP806_PLL_CR_0_CPU_CLK_RELOAD_FORCE_OFFSET 24
+#define AP806_PLL_CR_0_CPU_CLK_RELOAD_FORCE_MASK \
+ (0x1 << AP806_PLL_CR_0_CPU_CLK_RELOAD_FORCE_OFFSET)
+#define AP806_PLL_CR_0_CPU_CLK_RELOAD_RATIO_OFFSET 16
+#define AP806_CA72MP2_0_PLL_RATIO_STATE 11
+
+#define STATUS_POLL_PERIOD_US 1
+#define STATUS_POLL_TIMEOUT_US 1000000
+
+#define to_ap_cpu_clk(_hw) container_of(_hw, struct ap_cpu_clk, hw)
+
+/*
+ * struct ap806_clk: CPU cluster clock controller instance
+ * @cluster: Cluster clock controller index
+ * @clk_name: Cluster clock controller name
+ * @dev : Cluster clock device
+ * @hw: HW specific structure of Cluster clock controller
+ * @pll_cr_base: CA72MP2 Register base (Device Sample at Reset register)
+ */
+struct ap_cpu_clk {
+ unsigned int cluster;
+ const char *clk_name;
+ struct device *dev;
+ struct clk_hw hw;
+ struct regmap *pll_cr_base;
+};
+
+static unsigned long ap_cpu_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ap_cpu_clk *clk = to_ap_cpu_clk(hw);
+ unsigned int cpu_clkdiv_reg;
+ int cpu_clkdiv_ratio;
+
+ cpu_clkdiv_reg = AP806_CA72MP2_0_PLL_CR_0_REG_OFFSET +
+ (clk->cluster * AP806_CA72MP2_0_PLL_CR_CLUSTER_OFFSET);
+ regmap_read(clk->pll_cr_base, cpu_clkdiv_reg, &cpu_clkdiv_ratio);
+ cpu_clkdiv_ratio &= AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_MASK;
+ cpu_clkdiv_ratio >>= AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_OFFSET;
+
+ return parent_rate / cpu_clkdiv_ratio;
+}
+
+static int ap_cpu_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ap_cpu_clk *clk = to_ap_cpu_clk(hw);
+ int ret, reg, divider = parent_rate / rate;
+ unsigned int cpu_clkdiv_reg, cpu_force_reg, cpu_ratio_reg, stable_bit;
+
+ cpu_clkdiv_reg = AP806_CA72MP2_0_PLL_CR_0_REG_OFFSET +
+ (clk->cluster * AP806_CA72MP2_0_PLL_CR_CLUSTER_OFFSET);
+ cpu_force_reg = AP806_CA72MP2_0_PLL_CR_1_REG_OFFSET +
+ (clk->cluster * AP806_CA72MP2_0_PLL_CR_CLUSTER_OFFSET);
+ cpu_ratio_reg = AP806_CA72MP2_0_PLL_CR_2_REG_OFFSET +
+ (clk->cluster * AP806_CA72MP2_0_PLL_CR_CLUSTER_OFFSET);
+
+ regmap_update_bits(clk->pll_cr_base, cpu_clkdiv_reg,
+ AP806_PLL_CR_0_CPU_CLK_DIV_RATIO_MASK, divider);
+
+ regmap_update_bits(clk->pll_cr_base, cpu_force_reg,
+ AP806_PLL_CR_0_CPU_CLK_RELOAD_FORCE_MASK,
+ AP806_PLL_CR_0_CPU_CLK_RELOAD_FORCE_MASK);
+
+ regmap_update_bits(clk->pll_cr_base, cpu_ratio_reg,
+ BIT(AP806_PLL_CR_0_CPU_CLK_RELOAD_RATIO_OFFSET),
+ BIT(AP806_PLL_CR_0_CPU_CLK_RELOAD_RATIO_OFFSET));
+
+ stable_bit = BIT(clk->cluster * AP806_CA72MP2_0_PLL_RATIO_STATE),
+
+ ret = regmap_read_poll_timeout(clk->pll_cr_base,
+ AP806_CA72MP2_0_PLL_SR_REG_OFFSET, reg,
+ reg & stable_bit, STATUS_POLL_PERIOD_US,
+ STATUS_POLL_TIMEOUT_US);
+ if (ret)
+ return ret;
+
+ regmap_update_bits(clk->pll_cr_base, cpu_ratio_reg,
+ BIT(AP806_PLL_CR_0_CPU_CLK_RELOAD_RATIO_OFFSET), 0);
+
+ return 0;
+}
+
+static long ap_cpu_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ int divider = *parent_rate / rate;
+
+ divider = min(divider, APN806_MAX_DIVIDER);
+
+ return *parent_rate / divider;
+}
+
+static const struct clk_ops ap_cpu_clk_ops = {
+ .recalc_rate = ap_cpu_clk_recalc_rate,
+ .round_rate = ap_cpu_clk_round_rate,
+ .set_rate = ap_cpu_clk_set_rate,
+};
+
+static int ap_cpu_clock_probe(struct platform_device *pdev)
+{
+ int ret, nclusters = 0, cluster_index = 0;
+ struct device *dev = &pdev->dev;
+ struct device_node *dn, *np = dev->of_node;
+ struct clk_hw_onecell_data *ap_cpu_data;
+ struct ap_cpu_clk *ap_cpu_clk;
+ struct regmap *regmap;
+
+ regmap = syscon_node_to_regmap(np->parent);
+ if (IS_ERR(regmap)) {
+ pr_err("cannot get pll_cr_base regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ /*
+ * AP806 has 4 cpus and DFS for AP806 is controlled per
+ * cluster (2 CPUs per cluster), cpu0 and cpu1 are fixed to
+ * cluster0 while cpu2 and cpu3 are fixed to cluster1 whether
+ * they are enabled or not. Since cpu0 is the boot cpu, then
+ * cluster0 must exist. If cpu2 or cpu3 is enabled, cluster1
+ * will exist and the cluster number is 2; otherwise the
+ * cluster number is 1.
+ */
+ nclusters = 1;
+ for_each_of_cpu_node(dn) {
+ int cpu, err;
+
+ err = of_property_read_u32(dn, "reg", &cpu);
+ if (WARN_ON(err))
+ return err;
+
+ /* If cpu2 or cpu3 is enabled */
+ if (cpu & APN806_CLUSTER_NUM_MASK) {
+ nclusters = 2;
+ break;
+ }
+ }
+ /*
+ * DFS for AP806 is controlled per cluster (2 CPUs per cluster),
+ * so allocate structs per cluster
+ */
+ ap_cpu_clk = devm_kcalloc(dev, nclusters, sizeof(*ap_cpu_clk),
+ GFP_KERNEL);
+ if (!ap_cpu_clk)
+ return -ENOMEM;
+
+ ap_cpu_data = devm_kzalloc(dev, sizeof(*ap_cpu_data) +
+ sizeof(struct clk_hw *) * nclusters,
+ GFP_KERNEL);
+ if (!ap_cpu_data)
+ return -ENOMEM;
+
+ for_each_of_cpu_node(dn) {
+ char *clk_name = "cpu-cluster-0";
+ struct clk_init_data init;
+ const char *parent_name;
+ struct clk *parent;
+ int cpu, err;
+
+ err = of_property_read_u32(dn, "reg", &cpu);
+ if (WARN_ON(err))
+ return err;
+
+ cluster_index = cpu & APN806_CLUSTER_NUM_MASK;
+ cluster_index >>= APN806_CLUSTER_NUM_OFFSET;
+
+ /* Initialize once for one cluster */
+ if (ap_cpu_data->hws[cluster_index])
+ continue;
+
+ parent = of_clk_get(np, cluster_index);
+ if (IS_ERR(parent)) {
+ dev_err(dev, "Could not get the clock parent\n");
+ return -EINVAL;
+ }
+ parent_name = __clk_get_name(parent);
+ clk_name[12] += cluster_index;
+ ap_cpu_clk[cluster_index].clk_name =
+ ap_cp_unique_name(dev, np->parent, clk_name);
+ ap_cpu_clk[cluster_index].cluster = cluster_index;
+ ap_cpu_clk[cluster_index].pll_cr_base = regmap;
+ ap_cpu_clk[cluster_index].hw.init = &init;
+ ap_cpu_clk[cluster_index].dev = dev;
+
+ init.name = ap_cpu_clk[cluster_index].clk_name;
+ init.ops = &ap_cpu_clk_ops;
+ init.num_parents = 1;
+ init.parent_names = &parent_name;
+
+ ret = devm_clk_hw_register(dev, &ap_cpu_clk[cluster_index].hw);
+ if (ret)
+ return ret;
+ ap_cpu_data->hws[cluster_index] = &ap_cpu_clk[cluster_index].hw;
+ }
+
+ ap_cpu_data->num = cluster_index + 1;
+
+ ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, ap_cpu_data);
+ if (ret)
+ dev_err(dev, "failed to register OF clock provider\n");
+
+ return ret;
+}
+
+static const struct of_device_id ap_cpu_clock_of_match[] = {
+ { .compatible = "marvell,ap806-cpu-clock", },
+ { }
+};
+
+static struct platform_driver ap_cpu_clock_driver = {
+ .probe = ap_cpu_clock_probe,
+ .driver = {
+ .name = "marvell-ap-cpu-clock",
+ .of_match_table = ap_cpu_clock_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+builtin_platform_driver(ap_cpu_clock_driver);
--
2.19.2
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