[PATCH 3/9] clk: stm32: add STM32H7RS RCC driver

[Liu Changjie]

Register the active STM32H7RS system, bus and selected peripheral
clocks without reprogramming the PLLs used for execute-in-place.
Decode the PLL2 S and T outputs used by SDMMC from PLL2DIVR2.
Expose gates for TIM5, UART4, GPIO banks A-H and M-P, and SDMMC1.

Signed-off-by: Liu Changjie <liucj1228@xxxxxxxxxxx>
---
 drivers/clk/Kconfig         |   5 +
 drivers/clk/Makefile        |   1 +
 drivers/clk/clk-stm32h7rs.c | 466 ++++++++++++++++++++++++++++++++++++
 3 files changed, 472 insertions(+)
 create mode 100644 drivers/clk/clk-stm32h7rs.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 1717ce75a..5d1562a8a 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -448,6 +448,11 @@ config COMMON_CLK_STM32H7
 	help
 	  Support for stm32h7 SoC family clocks
 
+config COMMON_CLK_STM32H7RS
+	def_bool COMMON_CLK && MACH_STM32H7R7
+	help
+	  Support for STM32H7RS SoC family clocks
+
 config COMMON_CLK_MMP2
 	def_bool COMMON_CLK && (MACH_MMP2_DT || MACH_MMP3_DT)
 	help
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index cc108a75a..3dcb2f525 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -98,6 +98,7 @@ obj-$(CONFIG_COMMON_CLK_SI570)		+= clk-si570.o
 obj-$(CONFIG_COMMON_CLK_SP7021)		+= clk-sp7021.o
 obj-$(CONFIG_COMMON_CLK_STM32F)		+= clk-stm32f4.o
 obj-$(CONFIG_COMMON_CLK_STM32H7)	+= clk-stm32h7.o
+obj-$(CONFIG_COMMON_CLK_STM32H7RS)	+= clk-stm32h7rs.o
 obj-$(CONFIG_COMMON_CLK_TPS68470)      += clk-tps68470.o
 obj-$(CONFIG_CLK_TWL6040)		+= clk-twl6040.o
 obj-$(CONFIG_CLK_TWL)			+= clk-twl.o
diff --git a/drivers/clk/clk-stm32h7rs.c b/drivers/clk/clk-stm32h7rs.c
new file mode 100644
index 000000000..b82a24822
--- /dev/null
+++ b/drivers/clk/clk-stm32h7rs.c
@@ -0,0 +1,466 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Clock driver for the STM32H7RS Reset and Clock Controller.
+ *
+ * The first-stage firmware configures the oscillators and PLLs before Linux
+ * starts executing from external NOR.  The driver reconstructs that running
+ * clock tree from RCC registers and gives Linux ownership of peripheral clock
+ * gates without disturbing the XIP-critical PLL configuration.
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_clk.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <dt-bindings/clock/stm32h7rs-clks.h>
+
+#define RCC_CR			0x000
+#define RCC_CFGR		0x010
+#define RCC_CDCFGR		0x018
+#define RCC_BMCFGR		0x01c
+#define RCC_APBCFGR		0x020
+#define RCC_PLLCKSELR		0x028
+#define RCC_PLLCFGR		0x02c
+#define RCC_PLL1DIVR1		0x030
+#define RCC_PLL1FRACR		0x034
+#define RCC_PLL2DIVR1		0x038
+#define RCC_PLL2FRACR		0x03c
+#define RCC_PLL3DIVR1		0x040
+#define RCC_PLL3FRACR		0x044
+#define RCC_CCIPR1		0x04c
+#define RCC_CCIPR2		0x050
+#define RCC_PLL2DIVR2		0x0c4
+#define RCC_AHB5ENR		0x134
+#define RCC_AHB4ENR		0x140
+#define RCC_APB1ENR1		0x148
+
+#define RCC_CR_HSIDIV_SHIFT	3
+#define RCC_CFGR_SWS_SHIFT	3
+#define RCC_CFGR_TIMPRE		BIT(15)
+#define RCC_PLLCFGR_FRACEN(_pll)	BIT(((_pll) - 1) * 11)
+#define RCC_PLL_ON(_pll)	BIT(24 + (((_pll) - 1) * 2))
+
+#define RCC_CDCFGR_CPRE_SHIFT	0
+#define RCC_BMCFGR_BMPRE_SHIFT	0
+#define RCC_APBCFGR_PPRE1_SHIFT	0
+#define RCC_APBCFGR_PPRE2_SHIFT	4
+#define RCC_APBCFGR_PPRE4_SHIFT	8
+#define RCC_APBCFGR_PPRE5_SHIFT	12
+
+#define RCC_CCIPR1_SDMMC12SEL	BIT(2)
+#define RCC_CCIPR2_UARTSEL_MASK	GENMASK(2, 0)
+
+#define HSI_RATE		64000000UL
+#define CSI_RATE		4000000UL
+
+static DEFINE_SPINLOCK(stm32h7rs_rcc_lock);
+
+static const u16 pll_divr_offset[] = {
+	RCC_PLL1DIVR1, RCC_PLL2DIVR1, RCC_PLL3DIVR1,
+};
+
+static const u16 pll_fracr_offset[] = {
+	RCC_PLL1FRACR, RCC_PLL2FRACR, RCC_PLL3FRACR,
+};
+
+static const u8 pll_m_shift[] = { 4, 12, 20 };
+
+enum stm32h7rs_pll_output {
+	PLL_P,
+	PLL_Q,
+	PLL_R,
+	PLL_S,
+	PLL_T,
+};
+
+static unsigned long stm32h7rs_hsi_rate(void __iomem *base)
+{
+	u32 div = (readl_relaxed(base + RCC_CR) >> RCC_CR_HSIDIV_SHIFT) & 0x3;
+
+	return HSI_RATE >> div;
+}
+
+static unsigned long stm32h7rs_pll_rate(void __iomem *base, unsigned int pll,
+					unsigned int output,
+					unsigned long hse_rate)
+{
+	static const u8 output_shift[] = { 9, 16, 24 };
+	u64 numerator;
+	unsigned long parent_rate;
+	u32 divr1, frac = 0, m, n, out_div, source;
+
+	if (pll < 1 || pll > ARRAY_SIZE(pll_divr_offset) || output > PLL_T)
+		return 0;
+
+	if (output > PLL_R && pll != 2)
+		return 0;
+
+	if (!(readl_relaxed(base + RCC_CR) & RCC_PLL_ON(pll)))
+		return 0;
+
+	source = readl_relaxed(base + RCC_PLLCKSELR) & GENMASK(1, 0);
+	switch (source) {
+	case 0:
+		parent_rate = stm32h7rs_hsi_rate(base);
+		break;
+	case 1:
+		parent_rate = CSI_RATE;
+		break;
+	case 2:
+		parent_rate = hse_rate;
+		break;
+	default:
+		return 0;
+	}
+
+	m = (readl_relaxed(base + RCC_PLLCKSELR) >> pll_m_shift[pll - 1]) & 0x3f;
+	if (!m || !parent_rate)
+		return 0;
+
+	divr1 = readl_relaxed(base + pll_divr_offset[pll - 1]);
+	n = (divr1 & GENMASK(8, 0)) + 1;
+	if (readl_relaxed(base + RCC_PLLCFGR) & RCC_PLLCFGR_FRACEN(pll))
+		frac = (readl_relaxed(base + pll_fracr_offset[pll - 1]) >> 3) &
+			GENMASK(12, 0);
+
+	if (output <= PLL_R) {
+		out_div = ((divr1 >> output_shift[output]) &
+			   GENMASK(6, 0)) + 1;
+	} else {
+		u32 divr2 = readl_relaxed(base + RCC_PLL2DIVR2);
+		u8 shift = output == PLL_S ? 0 : 8;
+
+		out_div = ((divr2 >> shift) & GENMASK(2, 0)) + 1;
+	}
+
+	numerator = (u64)parent_rate * (n * 8192ULL + frac);
+	return div64_u64(numerator, (u64)m * 8192ULL * out_div);
+}
+
+static unsigned long stm32h7rs_ahb_rate(unsigned long parent_rate, u32 val)
+{
+	static const u16 div_table[] = { 2, 4, 8, 16, 64, 128, 256, 512 };
+
+	if (val < 8)
+		return parent_rate;
+
+	return parent_rate / div_table[val - 8];
+}
+
+static unsigned long stm32h7rs_sys_rate(void __iomem *base,
+					unsigned long hse_rate)
+{
+	unsigned long rate;
+	u32 cpre, source;
+
+	source = (readl_relaxed(base + RCC_CFGR) >> RCC_CFGR_SWS_SHIFT) & 0x7;
+	switch (source) {
+	case 0:
+		rate = stm32h7rs_hsi_rate(base);
+		break;
+	case 1:
+		rate = CSI_RATE;
+		break;
+	case 2:
+		rate = hse_rate;
+		break;
+	case 3:
+		rate = stm32h7rs_pll_rate(base, 1, PLL_P, hse_rate);
+		break;
+	default:
+		return 0;
+	}
+
+	cpre = (readl_relaxed(base + RCC_CDCFGR) >> RCC_CDCFGR_CPRE_SHIFT) & 0xf;
+	return stm32h7rs_ahb_rate(rate, cpre);
+}
+
+static unsigned long stm32h7rs_apb_rate(void __iomem *base,
+					unsigned long hclk_rate, u8 shift)
+{
+	u32 prescaler = (readl_relaxed(base + RCC_APBCFGR) >> shift) & 0x7;
+
+	if (prescaler < 4)
+		return hclk_rate;
+
+	return hclk_rate >> (prescaler - 3);
+}
+
+static unsigned long stm32h7rs_timer_rate(void __iomem *base,
+					  unsigned long hclk_rate,
+					  unsigned long pclk_rate)
+{
+	u32 prescaler = (readl_relaxed(base + RCC_APBCFGR) >>
+			 RCC_APBCFGR_PPRE1_SHIFT) & 0x7;
+
+	if (prescaler < 4)
+		return pclk_rate;
+
+	if (!(readl_relaxed(base + RCC_CFGR) & RCC_CFGR_TIMPRE))
+		return pclk_rate * 2;
+
+	return prescaler < 6 ? hclk_rate : pclk_rate * 4;
+}
+
+static unsigned long stm32h7rs_uart4_rate(void __iomem *base,
+					  unsigned long hse_rate,
+					  unsigned long lse_rate,
+					  unsigned long pclk1_rate)
+{
+	u32 source = readl_relaxed(base + RCC_CCIPR2) & RCC_CCIPR2_UARTSEL_MASK;
+
+	switch (source) {
+	case 0:
+		return pclk1_rate;
+	case 1:
+		return stm32h7rs_pll_rate(base, 2, PLL_Q, hse_rate);
+	case 2:
+		return stm32h7rs_pll_rate(base, 3, PLL_Q, hse_rate);
+	case 3:
+		return stm32h7rs_hsi_rate(base);
+	case 4:
+		return CSI_RATE;
+	case 5:
+		return lse_rate;
+	default:
+		return 0;
+	}
+}
+
+static unsigned long stm32h7rs_sdmmc1_rate(void __iomem *base,
+					   unsigned long hse_rate)
+{
+	if (readl_relaxed(base + RCC_CCIPR1) & RCC_CCIPR1_SDMMC12SEL)
+		return stm32h7rs_pll_rate(base, 2, PLL_T, hse_rate);
+
+	return stm32h7rs_pll_rate(base, 2, PLL_S, hse_rate);
+}
+
+static int __init h7rs_register_fixed(struct clk_hw_onecell_data *data,
+				      unsigned int id, const char *name,
+				       unsigned long rate)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_fixed_rate(NULL, name, NULL, CLK_IS_CRITICAL, rate);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+
+	data->hws[id] = hw;
+	return 0;
+}
+
+static int __init h7rs_register_gate(struct clk_hw_onecell_data *data,
+				     unsigned int id, const char *name,
+				      const char *parent_name,
+				      void __iomem *base, u16 offset,
+				      u8 bit_idx)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_gate(NULL, name, parent_name, CLK_IGNORE_UNUSED,
+				  base + offset, bit_idx, 0,
+				  &stm32h7rs_rcc_lock);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+
+	data->hws[id] = hw;
+	return 0;
+}
+
+struct stm32h7rs_gate {
+	u8 id;
+	u8 bit_idx;
+	u16 offset;
+	const char *name;
+	const char *parent_name;
+};
+
+static const struct stm32h7rs_gate stm32h7rs_gates[] __initconst = {
+	{ STM32H7RS_TIM5_CK, 3, RCC_APB1ENR1, "tim5", "tim5_ker" },
+	{ STM32H7RS_UART4_CK, 19, RCC_APB1ENR1, "uart4", "uart4_ker" },
+	{ STM32H7RS_GPIOA_CK, 0, RCC_AHB4ENR, "gpioa", "h7rs_hclk" },
+	{ STM32H7RS_GPIOB_CK, 1, RCC_AHB4ENR, "gpiob", "h7rs_hclk" },
+	{ STM32H7RS_GPIOC_CK, 2, RCC_AHB4ENR, "gpioc", "h7rs_hclk" },
+	{ STM32H7RS_GPIOD_CK, 3, RCC_AHB4ENR, "gpiod", "h7rs_hclk" },
+	{ STM32H7RS_GPIOE_CK, 4, RCC_AHB4ENR, "gpioe", "h7rs_hclk" },
+	{ STM32H7RS_GPIOF_CK, 5, RCC_AHB4ENR, "gpiof", "h7rs_hclk" },
+	{ STM32H7RS_GPIOG_CK, 6, RCC_AHB4ENR, "gpiog", "h7rs_hclk" },
+	{ STM32H7RS_GPIOH_CK, 7, RCC_AHB4ENR, "gpioh", "h7rs_hclk" },
+	{ STM32H7RS_GPIOM_CK, 12, RCC_AHB4ENR, "gpiom", "h7rs_hclk" },
+	{ STM32H7RS_GPION_CK, 13, RCC_AHB4ENR, "gpion", "h7rs_hclk" },
+	{ STM32H7RS_GPIOO_CK, 14, RCC_AHB4ENR, "gpioo", "h7rs_hclk" },
+	{ STM32H7RS_GPIOP_CK, 15, RCC_AHB4ENR, "gpiop", "h7rs_hclk" },
+	{ STM32H7RS_SDMMC1_CK, 8, RCC_AHB5ENR, "sdmmc1", "sdmmc1_ker" },
+};
+
+static void __init stm32h7rs_rcc_init(struct device_node *np)
+{
+	struct clk_hw_onecell_data *clk_data;
+	unsigned long hse_rate, lse_rate;
+	unsigned long sys_rate, hclk_rate;
+	unsigned long pclk1_rate, pclk2_rate, pclk4_rate, pclk5_rate;
+	unsigned long timer_rate, uart4_rate, sdmmc1_rate;
+	struct clk_hw *timer_hw = NULL, *uart4_hw = NULL, *sdmmc1_hw = NULL;
+	struct clk *input;
+	void __iomem *base;
+	unsigned int fixed_count = 0, gate_count = 0;
+	unsigned int i;
+	u32 bmpre;
+	int ret;
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		pr_err("%pOF: unable to map RCC registers\n", np);
+		return;
+	}
+
+	input = of_clk_get(np, 0);
+	if (IS_ERR(input)) {
+		pr_err("%pOF: unable to get HSE input clock\n", np);
+		goto err_unmap;
+	}
+	hse_rate = clk_get_rate(input);
+	clk_put(input);
+
+	input = of_clk_get(np, 1);
+	if (IS_ERR(input)) {
+		pr_err("%pOF: unable to get LSE input clock\n", np);
+		goto err_unmap;
+	}
+	lse_rate = clk_get_rate(input);
+	clk_put(input);
+
+	clk_data = kzalloc(struct_size(clk_data, hws, STM32H7RS_MAX_CLKS),
+			   GFP_KERNEL);
+	if (!clk_data)
+		goto err_unmap;
+	clk_data->num = STM32H7RS_MAX_CLKS;
+
+	sys_rate = stm32h7rs_sys_rate(base, hse_rate);
+	bmpre = (readl_relaxed(base + RCC_BMCFGR) >>
+		  RCC_BMCFGR_BMPRE_SHIFT) & 0xf;
+	hclk_rate = stm32h7rs_ahb_rate(sys_rate, bmpre);
+	pclk1_rate = stm32h7rs_apb_rate(base, hclk_rate, RCC_APBCFGR_PPRE1_SHIFT);
+	pclk2_rate = stm32h7rs_apb_rate(base, hclk_rate, RCC_APBCFGR_PPRE2_SHIFT);
+	pclk4_rate = stm32h7rs_apb_rate(base, hclk_rate, RCC_APBCFGR_PPRE4_SHIFT);
+	pclk5_rate = stm32h7rs_apb_rate(base, hclk_rate, RCC_APBCFGR_PPRE5_SHIFT);
+	timer_rate = stm32h7rs_timer_rate(base, hclk_rate, pclk1_rate);
+	uart4_rate = stm32h7rs_uart4_rate(base, hse_rate, lse_rate, pclk1_rate);
+	sdmmc1_rate = stm32h7rs_sdmmc1_rate(base, hse_rate);
+
+	if (!sys_rate || !hclk_rate || !pclk1_rate || !pclk2_rate ||
+	    !pclk4_rate || !pclk5_rate || !timer_rate || !uart4_rate ||
+	    !sdmmc1_rate) {
+		pr_err("%pOF: invalid boot clock configuration\n", np);
+		goto err_free;
+	}
+
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_SYS_CK,
+				  "h7rs_sys_ck", sys_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_HCLK,
+				  "h7rs_hclk", hclk_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_PCLK1,
+				  "h7rs_pclk1", pclk1_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_PCLK2,
+				  "h7rs_pclk2", pclk2_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_PCLK4,
+				  "h7rs_pclk4", pclk4_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+	ret = h7rs_register_fixed(clk_data, STM32H7RS_PCLK5,
+				  "h7rs_pclk5", pclk5_rate);
+	if (ret)
+		goto err_register;
+	fixed_count++;
+
+	timer_hw = clk_hw_register_fixed_rate(NULL, "tim5_ker", NULL,
+					      CLK_IS_CRITICAL, timer_rate);
+	if (IS_ERR(timer_hw)) {
+		ret = PTR_ERR(timer_hw);
+		timer_hw = NULL;
+		goto err_register;
+	}
+	uart4_hw = clk_hw_register_fixed_rate(NULL, "uart4_ker", NULL,
+					      CLK_IS_CRITICAL, uart4_rate);
+	if (IS_ERR(uart4_hw)) {
+		ret = PTR_ERR(uart4_hw);
+		uart4_hw = NULL;
+		goto err_register;
+	}
+	sdmmc1_hw = clk_hw_register_fixed_rate(NULL, "sdmmc1_ker", NULL,
+					       CLK_IS_CRITICAL, sdmmc1_rate);
+	if (IS_ERR(sdmmc1_hw)) {
+		ret = PTR_ERR(sdmmc1_hw);
+		sdmmc1_hw = NULL;
+		goto err_register;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(stm32h7rs_gates); i++) {
+		const struct stm32h7rs_gate *gate = &stm32h7rs_gates[i];
+
+		ret = h7rs_register_gate(clk_data, gate->id, gate->name,
+					 gate->parent_name, base,
+					   gate->offset, gate->bit_idx);
+		if (ret) {
+			pr_err("%pOF: failed to register %s clock: %d\n",
+			       np, gate->name, ret);
+			goto err_register;
+		}
+		gate_count++;
+	}
+
+	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_data);
+	if (ret) {
+		pr_err("%pOF: failed to add clock provider: %d\n", np, ret);
+		goto err_register;
+	}
+
+	pr_info("STM32H7RS RCC: sys=%lu hclk=%lu pclk1=%lu tim5=%lu uart4=%lu sdmmc1=%lu\n",
+		sys_rate, hclk_rate, pclk1_rate, timer_rate, uart4_rate,
+		sdmmc1_rate);
+	return;
+
+err_register:
+	while (gate_count) {
+		const struct stm32h7rs_gate *gate;
+
+		gate = &stm32h7rs_gates[--gate_count];
+		clk_hw_unregister_gate(clk_data->hws[gate->id]);
+	}
+	if (sdmmc1_hw)
+		clk_hw_unregister_fixed_rate(sdmmc1_hw);
+	if (uart4_hw)
+		clk_hw_unregister_fixed_rate(uart4_hw);
+	if (timer_hw)
+		clk_hw_unregister_fixed_rate(timer_hw);
+	while (fixed_count)
+		clk_hw_unregister_fixed_rate(clk_data->hws[--fixed_count]);
+	pr_err("%pOF: failed to register clocks: %d\n", np, ret);
+err_free:
+	kfree(clk_data);
+err_unmap:
+	iounmap(base);
+}
+
+CLK_OF_DECLARE_DRIVER(stm32h7rs_rcc, "st,stm32h7rs-rcc", stm32h7rs_rcc_init);
-- 
2.55.0