Re: [PATCH 2/5] pmdomain: sunxi: add H6 PRCM PPU driver

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 21 Feb 2025 19:10:33 +0100
Jernej Škrabec <jernej.skrabec@gmail.com> wrote:

> Dne petek, 21. februar 2025 ob 01:57:59 Srednjeevropski standardni čas je Andre Przywara napisal(a):
> > The Allwinner Power Reset Clock Management (RPCM) block contains a few
> > bits that control some power domains. The most prominent one is the one
> > for the Mali GPU. On the Allwinner H6 this domain is enabled at reset, so
> > we didn't care about it so far, but the H616 defaults to it being disabled.
> > 
> > Add a power domain driver for those bits. Some BSP code snippets and
> > some spare documentation describe three bits, slightly different between
> > the H6 and H616, so add three power domains for each SoC, connected to
> > their compatible string.
> > 
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > ---
> >  drivers/pmdomain/sunxi/Kconfig              |  10 +
> >  drivers/pmdomain/sunxi/Makefile             |   1 +
> >  drivers/pmdomain/sunxi/sun50i-h6-prcm-ppu.c | 191 ++++++++++++++++++++
> >  3 files changed, 202 insertions(+)
> >  create mode 100644 drivers/pmdomain/sunxi/sun50i-h6-prcm-ppu.c
> > 
> > diff --git a/drivers/pmdomain/sunxi/Kconfig b/drivers/pmdomain/sunxi/Kconfig
> > index 17781bf8d86d7..43eecb3ea9819 100644
> > --- a/drivers/pmdomain/sunxi/Kconfig
> > +++ b/drivers/pmdomain/sunxi/Kconfig
> > @@ -8,3 +8,13 @@ config SUN20I_PPU
> >  	help
> >  	  Say y to enable the PPU power domain driver. This saves power
> >  	  when certain peripherals, such as the video engine, are idle.
> > +
> > +config SUN50I_H6_PRCM_PPU
> > +	tristate "Allwinner H6 PRCM power domain driver"
> > +	depends on ARCH_SUNXI || COMPILE_TEST
> > +	depends on PM
> > +	select PM_GENERIC_DOMAINS
> > +	help
> > +	  Say y to enable the Allwinner H6/H616 PRCM power domain driver.
> > +	  This is required to enable the Mali GPU in the H616 SoC, it is
> > +	  optional for the H6.
> > diff --git a/drivers/pmdomain/sunxi/Makefile b/drivers/pmdomain/sunxi/Makefile
> > index ec1d7a2fb21db..c1343e1237599 100644
> > --- a/drivers/pmdomain/sunxi/Makefile
> > +++ b/drivers/pmdomain/sunxi/Makefile
> > @@ -1,2 +1,3 @@
> >  # SPDX-License-Identifier: GPL-2.0-only
> >  obj-$(CONFIG_SUN20I_PPU)		+= sun20i-ppu.o
> > +obj-$(CONFIG_SUN50I_H6_PRCM_PPU)	+= sun50i-h6-prcm-ppu.o
> > diff --git a/drivers/pmdomain/sunxi/sun50i-h6-prcm-ppu.c b/drivers/pmdomain/sunxi/sun50i-h6-prcm-ppu.c
> > new file mode 100644
> > index 0000000000000..1c6b0c78b222d
> > --- /dev/null
> > +++ b/drivers/pmdomain/sunxi/sun50i-h6-prcm-ppu.c
> > @@ -0,0 +1,191 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright (C) Arm Ltd. 2024
> > + *
> > + * Allwinner H6/H616 PRCM power domain driver.
> > + * This covers a few registers inside the PRCM (Power Reset Clock Management)
> > + * block that control some power rails, most prominently for the Mali GPU.
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_domain.h>
> > +#include <linux/reset.h>
> > +
> > +/*
> > + * The PRCM block covers multiple devices, starting with some clocks,
> > + * then followed by the power rails.
> > + * The clocks are covered by a different driver, so this driver's MMIO range
> > + * starts later in the PRCM MMIO frame, not at the beginning of it.
> > + * To keep the register offsets consistent with other PRCM documentation,
> > + * express the registers relative to the beginning of the whole PRCM, and
> > + * subtract the PPU offset this driver is bound to.
> > + */
> > +#define PD_H6_PPU_OFFSET		0x250
> > +#define PD_H6_VDD_SYS_REG		0x250
> > +#define PD_H616_ANA_VDD_GATE			BIT(4)
> > +#define PD_H6_CPUS_VDD_GATE			BIT(3)
> > +#define PD_H6_AVCC_VDD_GATE			BIT(2)
> > +#define PD_H6_GPU_REG			0x254
> > +#define PD_H6_GPU_GATE				BIT(0)
> > +
> > +struct sun50i_h6_ppu_pd {
> > +	struct generic_pm_domain	genpd;
> > +	void __iomem			*reg;
> > +	u32				gate_mask;
> > +	bool				negated;
> > +};
> > +
> > +#define FLAG_PPU_ALWAYS_ON	BIT(0)
> > +#define FLAG_PPU_NEGATED	BIT(1)
> > +
> > +struct sun50i_h6_ppu_desc {
> > +	const char *name;
> > +	u32 offset;
> > +	u32 mask;
> > +	unsigned int flags;
> > +};
> > +
> > +struct sun50i_h6_ppu_desc sun50i_h6_ppus[] = {
> > +	{ "AVCC", PD_H6_VDD_SYS_REG, PD_H6_AVCC_VDD_GATE },
> > +	{ "CPUS", PD_H6_VDD_SYS_REG, PD_H6_CPUS_VDD_GATE },
> > +	{ "GPU", PD_H6_GPU_REG, PD_H6_GPU_GATE },
> > +	{}
> > +};
> > +
> > +struct sun50i_h6_ppu_desc sun50i_h616_ppus[] = {
> > +	{ "PLL", PD_H6_VDD_SYS_REG, PD_H6_AVCC_VDD_GATE,
> > +		FLAG_PPU_ALWAYS_ON | FLAG_PPU_NEGATED },
> > +	{ "ANA", PD_H6_VDD_SYS_REG, PD_H616_ANA_VDD_GATE, FLAG_PPU_ALWAYS_ON },
> > +	{ "GPU", PD_H6_GPU_REG, PD_H6_GPU_GATE, FLAG_PPU_NEGATED },
> > +	{}
> > +};
> > +#define to_sun50i_h6_ppu_pd(_genpd) \
> > +	container_of(_genpd, struct sun50i_h6_ppu_pd, genpd)
> > +
> > +static bool sun50i_h6_ppu_power_status(const struct sun50i_h6_ppu_pd *pd)
> > +{
> > +	bool bit = readl(pd->reg) & pd->gate_mask;
> > +
> > +	return bit ^ pd->negated;
> > +}
> > +
> > +static int sun50i_h6_ppu_pd_set_power(const struct sun50i_h6_ppu_pd *pd,
> > +				      bool set_bit)
> > +{
> > +	u32 reg = readl(pd->reg);
> > +
> > +	if (set_bit)
> > +		writel(reg | pd->gate_mask, pd->reg);
> > +	else
> > +		writel(reg & ~pd->gate_mask, pd->reg);
> > +
> > +	return 0;
> > +}
> > +
> > +static int sun50i_h6_ppu_pd_power_on(struct generic_pm_domain *genpd)
> > +{
> > +	const struct sun50i_h6_ppu_pd *pd = to_sun50i_h6_ppu_pd(genpd);
> > +
> > +	return sun50i_h6_ppu_pd_set_power(pd, !pd->negated);
> > +}
> > +
> > +static int sun50i_h6_ppu_pd_power_off(struct generic_pm_domain *genpd)
> > +{
> > +	const struct sun50i_h6_ppu_pd *pd = to_sun50i_h6_ppu_pd(genpd);
> > +
> > +	return sun50i_h6_ppu_pd_set_power(pd, pd->negated);
> > +}
> > +
> > +static int sun50i_h6_ppu_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct genpd_onecell_data *ppu;
> > +	struct sun50i_h6_ppu_pd *pds;
> > +	const struct sun50i_h6_ppu_desc *desc;
> > +	void __iomem *base;
> > +	int ret, i, count;
> > +
> > +	desc = of_device_get_match_data(dev);
> > +	if (!desc)
> > +		return -EINVAL;
> > +
> > +	for (count = 0; desc[count].name; count++)
> > +		;
> > +
> > +	pds = devm_kcalloc(dev, count, sizeof(*pds), GFP_KERNEL);
> > +	if (!pds)
> > +		return -ENOMEM;
> > +
> > +	ppu = devm_kzalloc(dev, sizeof(*ppu), GFP_KERNEL);
> > +	if (!ppu)
> > +		return -ENOMEM;
> > +
> > +	ppu->num_domains = count;
> > +	ppu->domains = devm_kcalloc(dev, count, sizeof(*ppu->domains),
> > +				    GFP_KERNEL);
> > +	if (!ppu->domains)
> > +		return -ENOMEM;
> > +
> > +	platform_set_drvdata(pdev, ppu);
> > +
> > +	base = devm_platform_ioremap_resource(pdev, 0);
> > +	if (IS_ERR(base))
> > +		return PTR_ERR(base);
> > +
> > +	for (i = 0; i < count; i++) {
> > +		struct sun50i_h6_ppu_pd *pd = &pds[i];
> > +
> > +		pd->genpd.name		= desc[i].name;
> > +		pd->genpd.power_off	= sun50i_h6_ppu_pd_power_off;
> > +		pd->genpd.power_on	= sun50i_h6_ppu_pd_power_on;
> > +		if (desc[i].flags & FLAG_PPU_ALWAYS_ON)
> > +			pd->genpd.flags = GENPD_FLAG_ALWAYS_ON;
> > +		pd->negated		= !!(desc[i].flags & FLAG_PPU_NEGATED);
> > +		pd->reg			= base + desc[i].offset - PD_H6_PPU_OFFSET;
> > +		pd->gate_mask		= desc[i].mask;
> > +
> > +		ret = pm_genpd_init(&pd->genpd, NULL,
> > +				    !sun50i_h6_ppu_power_status(pd));
> > +		if (ret) {
> > +			dev_warn(dev, "Failed to add GPU power domain: %d\n", ret);  
> 
> I suppose you want to replace "GPU" with desc[i].name.

Ah yeah, good point, fixed that.

> Otherwise it looks good to me, but I'd like to hear a comment from genpd maintainers.

Thanks!

Cheers,
Andre

> Best regards,
> Jernej
> 
> > +			return ret;
> > +		}
> > +		ppu->domains[i] = &pd->genpd;
> > +	}
> > +
> > +	ret = of_genpd_add_provider_onecell(dev->of_node, ppu);
> > +	if (ret)
> > +		dev_warn(dev, "Failed to add provider: %d\n", ret);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id sun50i_h6_ppu_of_match[] = {
> > +	{ .compatible	= "allwinner,sun50i-h6-prcm-ppu",
> > +	  .data		= &sun50i_h6_ppus },
> > +	{ .compatible	= "allwinner,sun50i-h616-prcm-ppu",
> > +	  .data		= &sun50i_h616_ppus },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, sun50i_h6_ppu_of_match);
> > +
> > +static struct platform_driver sun50i_h6_ppu_driver = {
> > +	.probe	= sun50i_h6_ppu_probe,
> > +	.driver	= {
> > +		.name			= "sun50i-h6-prcm-ppu",
> > +		.of_match_table		= sun50i_h6_ppu_of_match,
> > +		/* Power domains cannot be removed while they are in use. */
> > +		.suppress_bind_attrs	= true,
> > +	},
> > +};
> > +module_platform_driver(sun50i_h6_ppu_driver);
> > +
> > +MODULE_AUTHOR("Andre Przywara <andre.przywara@arm.com>");
> > +MODULE_DESCRIPTION("Allwinner H6 PRCM power domain driver");
> > +MODULE_LICENSE("GPL");
> >   
> 
> 
> 
>