pmdomain: Rename the genpd subsystem to pmdomain

It has been pointed out that naming a subsystem "genpd" isn't very
self-explanatory and the acronym itself that means Generic PM Domain, is
known only by a limited group of people.

In a way to improve the situation, let's rename the subsystem to pmdomain,
which ideally should indicate that this is about so called Power Domains or
"PM domains" as we often also use within the Linux Kernel terminology.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230912221127.487327-1-ulf.hansson@linaro.org

2 files changed, 209 insertions, 0 deletions

diff --git a/drivers/pmdomain/sunxi/Makefile b/drivers/pmdomain/sunxi/Makefile
new file mode 100644
index 000000000000..ec1d7a2fb21d
--- /dev/null
+++ b/drivers/pmdomain/sunxi/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_SUN20I_PPU)		+= sun20i-ppu.o
diff --git a/drivers/pmdomain/sunxi/sun20i-ppu.c b/drivers/pmdomain/sunxi/sun20i-ppu.c
new file mode 100644
index 000000000000..8700f9dd5f75
--- /dev/null
+++ b/drivers/pmdomain/sunxi/sun20i-ppu.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#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>
+
+#define PD_STATE_ON			1
+#define PD_STATE_OFF			2
+
+#define PD_RSTN_REG			0x00
+#define PD_CLK_GATE_REG			0x04
+#define PD_PWROFF_GATE_REG		0x08
+#define PD_PSW_ON_REG			0x0c
+#define PD_PSW_OFF_REG			0x10
+#define PD_PSW_DELAY_REG		0x14
+#define PD_OFF_DELAY_REG		0x18
+#define PD_ON_DELAY_REG			0x1c
+#define PD_COMMAND_REG			0x20
+#define PD_STATUS_REG			0x24
+#define PD_STATUS_COMPLETE			BIT(1)
+#define PD_STATUS_BUSY				BIT(3)
+#define PD_STATUS_STATE				GENMASK(17, 16)
+#define PD_ACTIVE_CTRL_REG		0x2c
+#define PD_GATE_STATUS_REG		0x30
+#define PD_RSTN_STATUS				BIT(0)
+#define PD_CLK_GATE_STATUS			BIT(1)
+#define PD_PWROFF_GATE_STATUS			BIT(2)
+#define PD_PSW_STATUS_REG		0x34
+
+#define PD_REGS_SIZE			0x80
+
+struct sun20i_ppu_desc {
+	const char *const		*names;
+	unsigned int			num_domains;
+};
+
+struct sun20i_ppu_pd {
+	struct generic_pm_domain	genpd;
+	void __iomem			*base;
+};
+
+#define to_sun20i_ppu_pd(_genpd) \
+	container_of(_genpd, struct sun20i_ppu_pd, genpd)
+
+static bool sun20i_ppu_pd_is_on(const struct sun20i_ppu_pd *pd)
+{
+	u32 status = readl(pd->base + PD_STATUS_REG);
+
+	return FIELD_GET(PD_STATUS_STATE, status) == PD_STATE_ON;
+}
+
+static int sun20i_ppu_pd_set_power(const struct sun20i_ppu_pd *pd, bool power_on)
+{
+	u32 state, status;
+	int ret;
+
+	if (sun20i_ppu_pd_is_on(pd) == power_on)
+		return 0;
+
+	/* Wait for the power controller to be idle. */
+	ret = readl_poll_timeout(pd->base + PD_STATUS_REG, status,
+				 !(status & PD_STATUS_BUSY), 100, 1000);
+	if (ret)
+		return ret;
+
+	state = power_on ? PD_STATE_ON : PD_STATE_OFF;
+	writel(state, pd->base + PD_COMMAND_REG);
+
+	/* Wait for the state transition to complete. */
+	ret = readl_poll_timeout(pd->base + PD_STATUS_REG, status,
+				 FIELD_GET(PD_STATUS_STATE, status) == state &&
+				 (status & PD_STATUS_COMPLETE), 100, 1000);
+	if (ret)
+		return ret;
+
+	/* Clear the completion flag. */
+	writel(status, pd->base + PD_STATUS_REG);
+
+	return 0;
+}
+
+static int sun20i_ppu_pd_power_on(struct generic_pm_domain *genpd)
+{
+	const struct sun20i_ppu_pd *pd = to_sun20i_ppu_pd(genpd);
+
+	return sun20i_ppu_pd_set_power(pd, true);
+}
+
+static int sun20i_ppu_pd_power_off(struct generic_pm_domain *genpd)
+{
+	const struct sun20i_ppu_pd *pd = to_sun20i_ppu_pd(genpd);
+
+	return sun20i_ppu_pd_set_power(pd, false);
+}
+
+static int sun20i_ppu_probe(struct platform_device *pdev)
+{
+	const struct sun20i_ppu_desc *desc;
+	struct device *dev = &pdev->dev;
+	struct genpd_onecell_data *ppu;
+	struct sun20i_ppu_pd *pds;
+	struct reset_control *rst;
+	void __iomem *base;
+	struct clk *clk;
+	int ret;
+
+	desc = of_device_get_match_data(dev);
+	if (!desc)
+		return -EINVAL;
+
+	pds = devm_kcalloc(dev, desc->num_domains, sizeof(*pds), GFP_KERNEL);
+	if (!pds)
+		return -ENOMEM;
+
+	ppu = devm_kzalloc(dev, sizeof(*ppu), GFP_KERNEL);
+	if (!ppu)
+		return -ENOMEM;
+
+	ppu->domains = devm_kcalloc(dev, desc->num_domains,
+				    sizeof(*ppu->domains), GFP_KERNEL);
+	if (!ppu->domains)
+		return -ENOMEM;
+
+	ppu->num_domains = desc->num_domains;
+	platform_set_drvdata(pdev, ppu);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	rst = devm_reset_control_get_exclusive(dev, NULL);
+	if (IS_ERR(rst))
+		return PTR_ERR(rst);
+
+	ret = reset_control_deassert(rst);
+	if (ret)
+		return ret;
+
+	for (unsigned int i = 0; i < ppu->num_domains; ++i) {
+		struct sun20i_ppu_pd *pd = &pds[i];
+
+		pd->genpd.name		= desc->names[i];
+		pd->genpd.power_off	= sun20i_ppu_pd_power_off;
+		pd->genpd.power_on	= sun20i_ppu_pd_power_on;
+		pd->base		= base + PD_REGS_SIZE * i;
+
+		ret = pm_genpd_init(&pd->genpd, NULL, sun20i_ppu_pd_is_on(pd));
+		if (ret) {
+			dev_warn(dev, "Failed to add '%s' domain: %d\n",
+				 pd->genpd.name, ret);
+			continue;
+		}
+
+		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 char *const sun20i_d1_ppu_pd_names[] = {
+	"CPU",
+	"VE",
+	"DSP",
+};
+
+static const struct sun20i_ppu_desc sun20i_d1_ppu_desc = {
+	.names		= sun20i_d1_ppu_pd_names,
+	.num_domains	= ARRAY_SIZE(sun20i_d1_ppu_pd_names),
+};
+
+static const struct of_device_id sun20i_ppu_of_match[] = {
+	{
+		.compatible	= "allwinner,sun20i-d1-ppu",
+		.data		= &sun20i_d1_ppu_desc,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sun20i_ppu_of_match);
+
+static struct platform_driver sun20i_ppu_driver = {
+	.probe	= sun20i_ppu_probe,
+	.driver	= {
+		.name			= "sun20i-ppu",
+		.of_match_table		= sun20i_ppu_of_match,
+		/* Power domains cannot be removed while they are in use. */
+		.suppress_bind_attrs	= true,
+	},
+};
+module_platform_driver(sun20i_ppu_driver);
+
+MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
+MODULE_DESCRIPTION("Allwinner D1 PPU power domain driver");
+MODULE_LICENSE("GPL");