@@ -1,4 +1,11 @@
# SPDX-License-Identifier: GPL-2.0-only
+config MSTAR_MSC313_CPUPLL
+ bool "MStar CPUPLL driver"
+ depends on ARCH_MSTARV7 || COMPILE_TEST
+ default ARCH_MSTARV7
+ help
+ Support for the CPU PLL present on MStar/Sigmastar SoCs.
+
config MSTAR_MSC313_MPLL
bool "MStar MPLL driver"
depends on ARCH_MSTARV7 || COMPILE_TEST
@@ -3,4 +3,5 @@
# Makefile for mstar specific clk
#
+obj-$(CONFIG_MSTAR_MSC313_CPUPLL) += clk-msc313-cpupll.o
obj-$(CONFIG_MSTAR_MSC313_MPLL) += clk-msc313-mpll.o
new file mode 100644
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Daniel Palmer <daniel@thingy.jp>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+/*
+ * This IP is not documented outside of the messy vendor driver.
+ * Below is what we think the registers look like based on looking at
+ * the vendor code and poking at the hardware:
+ *
+ * 0x140 -- LPF low. Seems to store one half of the clock transition
+ * 0x144 /
+ * 0x148 -- LPF high. Seems to store one half of the clock transition
+ * 0x14c /
+ * 0x150 -- vendor code says "toggle lpf enable"
+ * 0x154 -- mu?
+ * 0x15c -- lpf_update_count?
+ * 0x160 -- vendor code says "switch to LPF". Clock source config? Register bank?
+ * 0x164 -- vendor code says "from low to high" which seems to mean transition from LPF low to
+ * LPF high.
+ * 0x174 -- Seems to be the PLL lock status bit
+ * 0x180 -- Seems to be the current frequency, this might need to be populated by software?
+ * 0x184 / The vendor driver uses these to set the initial value of LPF low
+ *
+ * Frequency seems to be calculated like this:
+ * (parent clock (432mhz) / register_magic_value) * 16 * 524288
+ * Only the lower 24 bits of the resulting value will be used. In addition, the
+ * PLL doesn't seem to be able to lock on frequencies lower than 220 MHz, as
+ * divisor 0xfb586f (220 MHz) works but 0xfb7fff locks up.
+ *
+ * Vendor values:
+ * frequency - register value
+ *
+ * 400000000 - 0x0067AE14
+ * 600000000 - 0x00451EB8,
+ * 800000000 - 0x0033D70A,
+ * 1000000000 - 0x002978d4,
+ */
+
+#define REG_LPF_LOW_L 0x140
+#define REG_LPF_LOW_H 0x144
+#define REG_LPF_HIGH_BOTTOM 0x148
+#define REG_LPF_HIGH_TOP 0x14c
+#define REG_LPF_TOGGLE 0x150
+#define REG_LPF_MYSTERYTWO 0x154
+#define REG_LPF_UPDATE_COUNT 0x15c
+#define REG_LPF_MYSTERYONE 0x160
+#define REG_LPF_TRANSITIONCTRL 0x164
+#define REG_LPF_LOCK 0x174
+#define REG_CURRENT 0x180
+
+#define LPF_LOCK_TIMEOUT 100000000
+
+#define MULTIPLIER_1 16
+#define MULTIPLIER_2 524288
+#define MULTIPLIER (MULTIPLIER_1 * MULTIPLIER_2)
+
+struct msc313_cpupll {
+ void __iomem *base;
+ struct clk_hw clk_hw;
+};
+
+#define to_cpupll(_hw) container_of(_hw, struct msc313_cpupll, clk_hw)
+
+static u32 msc313_cpupll_reg_read32(struct msc313_cpupll *cpupll, unsigned int reg)
+{
+ u32 value;
+
+ value = ioread16(cpupll->base + reg + 4) << 16;
+ value |= ioread16(cpupll->base + reg);
+
+ return value;
+}
+
+static void msc313_cpupll_reg_write32(struct msc313_cpupll *cpupll, unsigned int reg, u32 value)
+{
+ u16 l = value & 0xffff, h = (value >> 16) & 0xffff;
+
+ iowrite16(l, cpupll->base + reg);
+ iowrite16(h, cpupll->base + reg + 4);
+}
+
+static void msc313_cpupll_setfreq(struct msc313_cpupll *cpupll, u32 regvalue)
+{
+ ktime_t timeout;
+
+ msc313_cpupll_reg_write32(cpupll, REG_LPF_HIGH_BOTTOM, regvalue);
+
+ iowrite16(0x1, cpupll->base + REG_LPF_MYSTERYONE);
+ iowrite16(0x6, cpupll->base + REG_LPF_MYSTERYTWO);
+ iowrite16(0x8, cpupll->base + REG_LPF_UPDATE_COUNT);
+ iowrite16(BIT(12), cpupll->base + REG_LPF_TRANSITIONCTRL);
+
+ iowrite16(0, cpupll->base + REG_LPF_TOGGLE);
+ iowrite16(1, cpupll->base + REG_LPF_TOGGLE);
+
+ timeout = ktime_add_ns(ktime_get(), LPF_LOCK_TIMEOUT);
+ while (!(ioread16(cpupll->base + REG_LPF_LOCK))) {
+ if (ktime_after(ktime_get(), timeout)) {
+ pr_err("timeout waiting for LPF_LOCK\n");
+ return;
+ }
+ cpu_relax();
+ }
+
+ iowrite16(0, cpupll->base + REG_LPF_TOGGLE);
+
+ msc313_cpupll_reg_write32(cpupll, REG_LPF_LOW_L, regvalue);
+}
+
+static unsigned long msc313_cpupll_frequencyforreg(u32 reg, unsigned long parent_rate)
+{
+ unsigned long long prescaled = ((unsigned long long)parent_rate) * MULTIPLIER;
+
+ if (prescaled == 0 || reg == 0)
+ return 0;
+ return DIV_ROUND_DOWN_ULL(prescaled, reg);
+}
+
+static u32 msc313_cpupll_regforfrequecy(unsigned long rate, unsigned long parent_rate)
+{
+ unsigned long long prescaled = ((unsigned long long)parent_rate) * MULTIPLIER;
+
+ if (prescaled == 0 || rate == 0)
+ return 0;
+ return DIV_ROUND_UP_ULL(prescaled, rate);
+}
+
+static unsigned long msc313_cpupll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+ struct msc313_cpupll *cpupll = to_cpupll(hw);
+
+ return msc313_cpupll_frequencyforreg(msc313_cpupll_reg_read32(cpupll, REG_LPF_LOW_L),
+ parent_rate);
+}
+
+static long msc313_cpupll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ u32 reg = msc313_cpupll_regforfrequecy(rate, *parent_rate);
+ long rounded = msc313_cpupll_frequencyforreg(reg, *parent_rate);
+
+ /*
+ * This is my poor attempt at making sure the resulting
+ * rate doesn't overshoot the requested rate.
+ */
+ for (; rounded >= rate && reg > 0; reg--)
+ rounded = msc313_cpupll_frequencyforreg(reg, *parent_rate);
+
+ return rounded;
+}
+
+static int msc313_cpupll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate)
+{
+ struct msc313_cpupll *cpupll = to_cpupll(hw);
+ u32 reg = msc313_cpupll_regforfrequecy(rate, parent_rate);
+
+ msc313_cpupll_setfreq(cpupll, reg);
+
+ return 0;
+}
+
+static const struct clk_ops msc313_cpupll_ops = {
+ .recalc_rate = msc313_cpupll_recalc_rate,
+ .round_rate = msc313_cpupll_round_rate,
+ .set_rate = msc313_cpupll_set_rate,
+};
+
+static const struct of_device_id msc313_cpupll_of_match[] = {
+ { .compatible = "mstar,msc313-cpupll" },
+ {}
+};
+
+static int msc313_cpupll_probe(struct platform_device *pdev)
+{
+ struct clk_init_data clk_init = {};
+ struct clk_parent_data cpupll_parent = { .index = 0 };
+ struct device *dev = &pdev->dev;
+ struct msc313_cpupll *cpupll;
+ int ret;
+
+ cpupll = devm_kzalloc(&pdev->dev, sizeof(*cpupll), GFP_KERNEL);
+ if (!cpupll)
+ return -ENOMEM;
+
+ cpupll->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(cpupll->base))
+ return PTR_ERR(cpupll->base);
+
+ /* LPF might not contain the current frequency so fix that up */
+ msc313_cpupll_reg_write32(cpupll, REG_LPF_LOW_L,
+ msc313_cpupll_reg_read32(cpupll, REG_CURRENT));
+
+ clk_init.name = dev_name(dev);
+ clk_init.ops = &msc313_cpupll_ops;
+ clk_init.parent_data = &cpupll_parent;
+ clk_init.num_parents = 1;
+ cpupll->clk_hw.init = &clk_init;
+
+ ret = devm_clk_hw_register(dev, &cpupll->clk_hw);
+ if (ret)
+ return ret;
+
+ return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, &cpupll->clk_hw);
+}
+
+static struct platform_driver msc313_cpupll_driver = {
+ .driver = {
+ .name = "mstar-msc313-cpupll",
+ .of_match_table = msc313_cpupll_of_match,
+ },
+ .probe = msc313_cpupll_probe,
+};
+builtin_platform_driver(msc313_cpupll_driver);