Re: [PATCH v12 1/1] clk: microchip: Add driver for Microchip PolarFire SoC

[<Conor.Dooley@microchip.com>]

Hey Stephen,

Could you take another look at this when you get a chance
& see if I addressed your comments on v9? [0]

Thanks,
Conor.

[0] https://lore.kernel.org/linux-clk/20220125004818.83E27C340E4@smtp.kernel.org/

On 22/02/2022 12:11, conor.dooley@microchip.com wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> Add support for clock configuration on Microchip PolarFire SoC
> 
> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Co-developed-by: Padmarao Begari <padmarao.begari@microchip.com>
> Signed-off-by: Padmarao Begari <padmarao.begari@microchip.com>
> Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
> Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>   drivers/clk/Kconfig              |   4 +-
>   drivers/clk/Makefile             |   2 +-
>   drivers/clk/microchip/Kconfig    |  10 +
>   drivers/clk/microchip/Makefile   |   1 +
>   drivers/clk/microchip/clk-mpfs.c | 381 +++++++++++++++++++++++++++++++
>   5 files changed, 394 insertions(+), 4 deletions(-)
>   create mode 100644 drivers/clk/microchip/Kconfig
>   create mode 100644 drivers/clk/microchip/clk-mpfs.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 4a8451f61f37..8dffd2d9ba38 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -331,9 +331,6 @@ config COMMON_CLK_PXA
>   	help
>   	  Support for the Marvell PXA SoC.
>   
> -config COMMON_CLK_PIC32
> -	def_bool COMMON_CLK && MACH_PIC32
> -
>   config COMMON_CLK_OXNAS
>   	bool "Clock driver for the OXNAS SoC Family"
>   	depends on ARCH_OXNAS || COMPILE_TEST
> @@ -408,6 +405,7 @@ source "drivers/clk/keystone/Kconfig"
>   source "drivers/clk/mediatek/Kconfig"
>   source "drivers/clk/meson/Kconfig"
>   source "drivers/clk/mstar/Kconfig"
> +source "drivers/clk/microchip/Kconfig"
>   source "drivers/clk/mvebu/Kconfig"
>   source "drivers/clk/pistachio/Kconfig"
>   source "drivers/clk/qcom/Kconfig"
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 6a98291350b6..3b0062746984 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -92,7 +92,7 @@ obj-$(CONFIG_ARCH_KEYSTONE)		+= keystone/
>   obj-$(CONFIG_MACH_LOONGSON32)		+= loongson1/
>   obj-y					+= mediatek/
>   obj-$(CONFIG_ARCH_MESON)		+= meson/
> -obj-$(CONFIG_MACH_PIC32)		+= microchip/
> +obj-y					+= microchip/
>   ifeq ($(CONFIG_COMMON_CLK), y)
>   obj-$(CONFIG_ARCH_MMP)			+= mmp/
>   endif
> diff --git a/drivers/clk/microchip/Kconfig b/drivers/clk/microchip/Kconfig
> new file mode 100644
> index 000000000000..a5a99873c4f5
> --- /dev/null
> +++ b/drivers/clk/microchip/Kconfig
> @@ -0,0 +1,10 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +config COMMON_CLK_PIC32
> +	def_bool COMMON_CLK && MACH_PIC32
> +
> +config MCHP_CLK_MPFS
> +	bool "Clk driver for PolarFire SoC"
> +	depends on (RISCV && SOC_MICROCHIP_POLARFIRE) || COMPILE_TEST
> +	help
> +	  Supports Clock Configuration for PolarFire SoC
> diff --git a/drivers/clk/microchip/Makefile b/drivers/clk/microchip/Makefile
> index f34b247e870f..5fa6dcf30a9a 100644
> --- a/drivers/clk/microchip/Makefile
> +++ b/drivers/clk/microchip/Makefile
> @@ -1,3 +1,4 @@
>   # SPDX-License-Identifier: GPL-2.0-only
>   obj-$(CONFIG_COMMON_CLK_PIC32) += clk-core.o
>   obj-$(CONFIG_PIC32MZDA) += clk-pic32mzda.o
> +obj-$(CONFIG_MCHP_CLK_MPFS) += clk-mpfs.o
> diff --git a/drivers/clk/microchip/clk-mpfs.c b/drivers/clk/microchip/clk-mpfs.c
> new file mode 100644
> index 000000000000..aa1561b773d6
> --- /dev/null
> +++ b/drivers/clk/microchip/clk-mpfs.c
> @@ -0,0 +1,381 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Daire McNamara,<daire.mcnamara@microchip.com>
> + * Copyright (C) 2020 Microchip Technology Inc.  All rights reserved.
> + */
> +#include <linux/clk-provider.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <dt-bindings/clock/microchip,mpfs-clock.h>
> +
> +/* address offset of control registers */
> +#define REG_CLOCK_CONFIG_CR	0x08u
> +#define REG_SUBBLK_CLOCK_CR	0x84u
> +#define REG_SUBBLK_RESET_CR	0x88u
> +
> +struct mpfs_clock_data {
> +	void __iomem *base;
> +	struct clk_hw_onecell_data hw_data;
> +};
> +
> +struct mpfs_cfg_clock {
> +	const struct clk_div_table *table;
> +	unsigned int id;
> +	u8 shift;
> +	u8 width;
> +};
> +
> +struct mpfs_cfg_hw_clock {
> +	struct mpfs_cfg_clock cfg;
> +	void __iomem *sys_base;
> +	struct clk_hw hw;
> +	struct clk_init_data init;
> +};
> +
> +#define to_mpfs_cfg_clk(_hw) container_of(_hw, struct mpfs_cfg_hw_clock, hw)
> +
> +struct mpfs_periph_clock {
> +	unsigned int id;
> +	u8 shift;
> +};
> +
> +struct mpfs_periph_hw_clock {
> +	struct mpfs_periph_clock periph;
> +	void __iomem *sys_base;
> +	struct clk_hw hw;
> +};
> +
> +#define to_mpfs_periph_clk(_hw) container_of(_hw, struct mpfs_periph_hw_clock, hw)
> +
> +/*
> + * mpfs_clk_lock prevents anything else from writing to the
> + * mpfs clk block while a software locked register is being written.
> + */
> +static DEFINE_SPINLOCK(mpfs_clk_lock);
> +
> +static const struct clk_parent_data mpfs_cfg_parent[] = {
> +	{ .index = 0 },
> +};
> +
> +static const struct clk_div_table mpfs_div_cpu_axi_table[] = {
> +	{ 0, 1 }, { 1, 2 }, { 2, 4 }, { 3, 8 },
> +	{ 0, 0 }
> +};
> +
> +static const struct clk_div_table mpfs_div_ahb_table[] = {
> +	{ 1, 2 }, { 2, 4}, { 3, 8 },
> +	{ 0, 0 }
> +};
> +
> +static unsigned long mpfs_cfg_clk_recalc_rate(struct clk_hw *hw, unsigned long prate)
> +{
> +	struct mpfs_cfg_hw_clock *cfg_hw = to_mpfs_cfg_clk(hw);
> +	struct mpfs_cfg_clock *cfg = &cfg_hw->cfg;
> +	void __iomem *base_addr = cfg_hw->sys_base;
> +	u32 val;
> +
> +	val = readl_relaxed(base_addr + REG_CLOCK_CONFIG_CR) >> cfg->shift;
> +	val &= clk_div_mask(cfg->width);
> +
> +	return prate / (1u << val);
> +}
> +
> +static long mpfs_cfg_clk_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *prate)
> +{
> +	struct mpfs_cfg_hw_clock *cfg_hw = to_mpfs_cfg_clk(hw);
> +	struct mpfs_cfg_clock *cfg = &cfg_hw->cfg;
> +
> +	return divider_round_rate(hw, rate, prate, cfg->table, cfg->width, 0);
> +}
> +
> +static int mpfs_cfg_clk_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long prate)
> +{
> +	struct mpfs_cfg_hw_clock *cfg_hw = to_mpfs_cfg_clk(hw);
> +	struct mpfs_cfg_clock *cfg = &cfg_hw->cfg;
> +	void __iomem *base_addr = cfg_hw->sys_base;
> +	unsigned long flags;
> +	u32 val;
> +	int divider_setting;
> +
> +	divider_setting = divider_get_val(rate, prate, cfg->table, cfg->width, 0);
> +
> +	if (divider_setting < 0)
> +		return divider_setting;
> +
> +	spin_lock_irqsave(&mpfs_clk_lock, flags);
> +
> +	val = readl_relaxed(base_addr + REG_CLOCK_CONFIG_CR);
> +	val &= ~(clk_div_mask(cfg->width) << cfg_hw->cfg.shift);
> +	val |= divider_setting << cfg->shift;
> +	writel_relaxed(val, base_addr + REG_CLOCK_CONFIG_CR);
> +
> +	spin_unlock_irqrestore(&mpfs_clk_lock, flags);
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops mpfs_clk_cfg_ops = {
> +	.recalc_rate = mpfs_cfg_clk_recalc_rate,
> +	.round_rate = mpfs_cfg_clk_round_rate,
> +	.set_rate = mpfs_cfg_clk_set_rate,
> +};
> +
> +#define CLK_CFG(_id, _name, _parent, _shift, _width, _table, _flags) {		\
> +	.cfg.id = _id,								\
> +	.cfg.shift = _shift,							\
> +	.cfg.width = _width,							\
> +	.cfg.table = _table,							\
> +	.hw.init = CLK_HW_INIT_PARENTS_DATA(_name, _parent, &mpfs_clk_cfg_ops,	\
> +					    _flags),				\
> +}
> +
> +static struct mpfs_cfg_hw_clock mpfs_cfg_clks[] = {
> +	CLK_CFG(CLK_CPU, "clk_cpu", mpfs_cfg_parent, 0, 2, mpfs_div_cpu_axi_table, 0),
> +	CLK_CFG(CLK_AXI, "clk_axi", mpfs_cfg_parent, 2, 2, mpfs_div_cpu_axi_table, 0),
> +	CLK_CFG(CLK_AHB, "clk_ahb", mpfs_cfg_parent, 4, 2, mpfs_div_ahb_table, 0),
> +};
> +
> +static int mpfs_clk_register_cfg(struct device *dev, struct mpfs_cfg_hw_clock *cfg_hw,
> +				 void __iomem *sys_base)
> +{
> +	cfg_hw->sys_base = sys_base;
> +
> +	return devm_clk_hw_register(dev, &cfg_hw->hw);
> +}
> +
> +static int mpfs_clk_register_cfgs(struct device *dev, struct mpfs_cfg_hw_clock *cfg_hws,
> +				  unsigned int num_clks, struct mpfs_clock_data *data)
> +{
> +	void __iomem *sys_base = data->base;
> +	unsigned int i, id;
> +	int ret;
> +
> +	for (i = 0; i < num_clks; i++) {
> +		struct mpfs_cfg_hw_clock *cfg_hw = &cfg_hws[i];
> +
> +		ret = mpfs_clk_register_cfg(dev, cfg_hw, sys_base);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "failed to register clock id: %d\n",
> +					     cfg_hw->cfg.id);
> +
> +		id = cfg_hws[i].cfg.id;
> +		data->hw_data.hws[id] = &cfg_hw->hw;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mpfs_periph_clk_enable(struct clk_hw *hw)
> +{
> +	struct mpfs_periph_hw_clock *periph_hw = to_mpfs_periph_clk(hw);
> +	struct mpfs_periph_clock *periph = &periph_hw->periph;
> +	void __iomem *base_addr = periph_hw->sys_base;
> +	u32 reg, val;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&mpfs_clk_lock, flags);
> +
> +	reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
> +	val = reg & ~(1u << periph->shift);
> +	writel_relaxed(val, base_addr + REG_SUBBLK_RESET_CR);
> +
> +	reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
> +	val = reg | (1u << periph->shift);
> +	writel_relaxed(val, base_addr + REG_SUBBLK_CLOCK_CR);
> +
> +	spin_unlock_irqrestore(&mpfs_clk_lock, flags);
> +
> +	return 0;
> +}
> +
> +static void mpfs_periph_clk_disable(struct clk_hw *hw)
> +{
> +	struct mpfs_periph_hw_clock *periph_hw = to_mpfs_periph_clk(hw);
> +	struct mpfs_periph_clock *periph = &periph_hw->periph;
> +	void __iomem *base_addr = periph_hw->sys_base;
> +	u32 reg, val;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&mpfs_clk_lock, flags);
> +
> +	reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
> +	val = reg | (1u << periph->shift);
> +	writel_relaxed(val, base_addr + REG_SUBBLK_RESET_CR);
> +
> +	reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
> +	val = reg & ~(1u << periph->shift);
> +	writel_relaxed(val, base_addr + REG_SUBBLK_CLOCK_CR);
> +
> +	spin_unlock_irqrestore(&mpfs_clk_lock, flags);
> +}
> +
> +static int mpfs_periph_clk_is_enabled(struct clk_hw *hw)
> +{
> +	struct mpfs_periph_hw_clock *periph_hw = to_mpfs_periph_clk(hw);
> +	struct mpfs_periph_clock *periph = &periph_hw->periph;
> +	void __iomem *base_addr = periph_hw->sys_base;
> +	u32 reg;
> +
> +	reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
> +	if ((reg & (1u << periph->shift)) == 0u) {
> +		reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
> +		if (reg & (1u << periph->shift))
> +			return 1;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops mpfs_periph_clk_ops = {
> +	.enable = mpfs_periph_clk_enable,
> +	.disable = mpfs_periph_clk_disable,
> +	.is_enabled = mpfs_periph_clk_is_enabled,
> +};
> +
> +#define CLK_PERIPH(_id, _name, _parent, _shift, _flags) {			\
> +	.periph.id = _id,							\
> +	.periph.shift = _shift,							\
> +	.hw.init = CLK_HW_INIT_HW(_name, _parent, &mpfs_periph_clk_ops,		\
> +				  _flags),					\
> +}
> +
> +#define PARENT_CLK(PARENT) (&mpfs_cfg_clks[CLK_##PARENT].hw)
> +
> +/*
> + * Critical clocks:
> + * - CLK_ENVM: reserved by hart software services (hss) superloop monitor/m mode interrupt
> + *   trap handler
> + * - CLK_MMUART0: reserved by the hss
> + * - CLK_DDRC: provides clock to the ddr subsystem
> + * - CLK_FICx: these provide clocks for sections of the fpga fabric, disabling them would
> + *   cause the fabric to go into reset
> + */
> +
> +static struct mpfs_periph_hw_clock mpfs_periph_clks[] = {
> +	CLK_PERIPH(CLK_ENVM, "clk_periph_envm", PARENT_CLK(AHB), 0, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_MAC0, "clk_periph_mac0", PARENT_CLK(AHB), 1, 0),
> +	CLK_PERIPH(CLK_MAC1, "clk_periph_mac1", PARENT_CLK(AHB), 2, 0),
> +	CLK_PERIPH(CLK_MMC, "clk_periph_mmc", PARENT_CLK(AHB), 3, 0),
> +	CLK_PERIPH(CLK_TIMER, "clk_periph_timer", PARENT_CLK(AHB), 4, 0),
> +	CLK_PERIPH(CLK_MMUART0, "clk_periph_mmuart0", PARENT_CLK(AHB), 5, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_MMUART1, "clk_periph_mmuart1", PARENT_CLK(AHB), 6, 0),
> +	CLK_PERIPH(CLK_MMUART2, "clk_periph_mmuart2", PARENT_CLK(AHB), 7, 0),
> +	CLK_PERIPH(CLK_MMUART3, "clk_periph_mmuart3", PARENT_CLK(AHB), 8, 0),
> +	CLK_PERIPH(CLK_MMUART4, "clk_periph_mmuart4", PARENT_CLK(AHB), 9, 0),
> +	CLK_PERIPH(CLK_SPI0, "clk_periph_spi0", PARENT_CLK(AHB), 10, 0),
> +	CLK_PERIPH(CLK_SPI1, "clk_periph_spi1", PARENT_CLK(AHB), 11, 0),
> +	CLK_PERIPH(CLK_I2C0, "clk_periph_i2c0", PARENT_CLK(AHB), 12, 0),
> +	CLK_PERIPH(CLK_I2C1, "clk_periph_i2c1", PARENT_CLK(AHB), 13, 0),
> +	CLK_PERIPH(CLK_CAN0, "clk_periph_can0", PARENT_CLK(AHB), 14, 0),
> +	CLK_PERIPH(CLK_CAN1, "clk_periph_can1", PARENT_CLK(AHB), 15, 0),
> +	CLK_PERIPH(CLK_USB, "clk_periph_usb", PARENT_CLK(AHB), 16, 0),
> +	CLK_PERIPH(CLK_RTC, "clk_periph_rtc", PARENT_CLK(AHB), 18, 0),
> +	CLK_PERIPH(CLK_QSPI, "clk_periph_qspi", PARENT_CLK(AHB), 19, 0),
> +	CLK_PERIPH(CLK_GPIO0, "clk_periph_gpio0", PARENT_CLK(AHB), 20, 0),
> +	CLK_PERIPH(CLK_GPIO1, "clk_periph_gpio1", PARENT_CLK(AHB), 21, 0),
> +	CLK_PERIPH(CLK_GPIO2, "clk_periph_gpio2", PARENT_CLK(AHB), 22, 0),
> +	CLK_PERIPH(CLK_DDRC, "clk_periph_ddrc", PARENT_CLK(AHB), 23, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_FIC0, "clk_periph_fic0", PARENT_CLK(AHB), 24, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_FIC1, "clk_periph_fic1", PARENT_CLK(AHB), 25, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_FIC2, "clk_periph_fic2", PARENT_CLK(AHB), 26, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_FIC3, "clk_periph_fic3", PARENT_CLK(AHB), 27, CLK_IS_CRITICAL),
> +	CLK_PERIPH(CLK_ATHENA, "clk_periph_athena", PARENT_CLK(AHB), 28, 0),
> +	CLK_PERIPH(CLK_CFM, "clk_periph_cfm", PARENT_CLK(AHB), 29, 0),
> +};
> +
> +static int mpfs_clk_register_periph(struct device *dev, struct mpfs_periph_hw_clock *periph_hw,
> +				    void __iomem *sys_base)
> +{
> +	periph_hw->sys_base = sys_base;
> +
> +	return devm_clk_hw_register(dev, &periph_hw->hw);
> +}
> +
> +static int mpfs_clk_register_periphs(struct device *dev, struct mpfs_periph_hw_clock *periph_hws,
> +				     int num_clks, struct mpfs_clock_data *data)
> +{
> +	void __iomem *sys_base = data->base;
> +	unsigned int i, id;
> +	int ret;
> +
> +	for (i = 0; i < num_clks; i++) {
> +		struct mpfs_periph_hw_clock *periph_hw = &periph_hws[i];
> +
> +		ret = mpfs_clk_register_periph(dev, periph_hw, sys_base);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "failed to register clock id: %d\n",
> +					     periph_hw->periph.id);
> +
> +		id = periph_hws[i].periph.id;
> +		data->hw_data.hws[id] = &periph_hw->hw;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mpfs_clk_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mpfs_clock_data *clk_data;
> +	unsigned int num_clks;
> +	int ret;
> +
> +	/* CLK_RESERVED is not part of cfg_clks nor periph_clks, so add 1 */
> +	num_clks = ARRAY_SIZE(mpfs_cfg_clks) + ARRAY_SIZE(mpfs_periph_clks) + 1;
> +
> +	clk_data = devm_kzalloc(dev, struct_size(clk_data, hw_data.hws, num_clks), GFP_KERNEL);
> +	if (!clk_data)
> +		return -ENOMEM;
> +
> +	clk_data->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(clk_data->base))
> +		return PTR_ERR(clk_data->base);
> +
> +	clk_data->hw_data.num = num_clks;
> +
> +	ret = mpfs_clk_register_cfgs(dev, mpfs_cfg_clks, ARRAY_SIZE(mpfs_cfg_clks), clk_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = mpfs_clk_register_periphs(dev, mpfs_periph_clks, ARRAY_SIZE(mpfs_periph_clks),
> +					clk_data);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, &clk_data->hw_data);
> +	if (ret)
> +		return ret;
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id mpfs_clk_of_match_table[] = {
> +	{ .compatible = "microchip,mpfs-clkcfg", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, mpfs_clk_match_table);
> +
> +static struct platform_driver mpfs_clk_driver = {
> +	.probe = mpfs_clk_probe,
> +	.driver	= {
> +		.name = "microchip-mpfs-clkcfg",
> +		.of_match_table = mpfs_clk_of_match_table,
> +	},
> +};
> +
> +static int __init clk_mpfs_init(void)
> +{
> +	return platform_driver_register(&mpfs_clk_driver);
> +}
> +core_initcall(clk_mpfs_init);
> +
> +static void __exit clk_mpfs_exit(void)
> +{
> +	platform_driver_unregister(&mpfs_clk_driver);
> +}
> +module_exit(clk_mpfs_exit);
> +
> +MODULE_DESCRIPTION("Microchip PolarFire SoC Clock Driver");
> +MODULE_LICENSE("GPL v2");