soc: imx: move PGC handling to a new GPC driver

This is an almost complete re-write of the previous GPC power gating control
code found in the IMX architecture code. It supports both the old and the new
DT binding, allowing more domains to be added later and generally makes the
driver easier to extend, while keeping compatibility with existing DTBs.

As the result, all functionality regarding the power gating controller
gets removed from the IMX architecture GPC driver.  It keeps only the
IRQ controller code in the architecture, as this is closely coupled to
the CPU idle implementation.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

2 files changed, 488 insertions, 0 deletions

diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
new file mode 100644
index 000000000000..35861f5b2802
--- /dev/null
+++ b/drivers/soc/imx/Makefile
@@ -0,0 +1 @@
+obj-y += gpc.o
diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
new file mode 100644
index 000000000000..1e9b3b81f466
--- /dev/null
+++ b/drivers/soc/imx/gpc.c
@@ -0,0 +1,487 @@
+/*
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@pengutronix.de>
+ * Copyright 2011-2013 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define GPC_CNTR		0x000
+
+#define GPC_PGC_PDN_OFFS	0x0
+#define GPC_PGC_PUPSCR_OFFS	0x4
+#define GPC_PGC_PDNSCR_OFFS	0x8
+#define GPC_PGC_SW2ISO_SHIFT	0x8
+#define GPC_PGC_SW_SHIFT	0x0
+
+#define GPC_PGC_GPU_PDN		0x260
+#define GPC_PGC_GPU_PUPSCR	0x264
+#define GPC_PGC_GPU_PDNSCR	0x268
+
+#define GPU_VPU_PUP_REQ		BIT(1)
+#define GPU_VPU_PDN_REQ		BIT(0)
+
+#define GPC_CLK_MAX		6
+
+struct imx_pm_domain {
+	struct generic_pm_domain base;
+	struct regmap *regmap;
+	struct regulator *supply;
+	struct clk *clk[GPC_CLK_MAX];
+	int num_clks;
+	unsigned int reg_offs;
+	signed char cntr_pdn_bit;
+	unsigned int ipg_rate_mhz;
+};
+
+static inline struct imx_pm_domain *
+to_imx_pm_domain(struct generic_pm_domain *genpd)
+{
+	return container_of(genpd, struct imx_pm_domain, base);
+}
+
+static int imx6_pm_domain_power_off(struct generic_pm_domain *genpd)
+{
+	struct imx_pm_domain *pd = to_imx_pm_domain(genpd);
+	int iso, iso2sw;
+	u32 val;
+
+	/* Read ISO and ISO2SW power down delays */
+	regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val);
+	iso = val & 0x3f;
+	iso2sw = (val >> 8) & 0x3f;
+
+	/* Gate off domain when powered down */
+	regmap_update_bits(pd->regmap, pd->reg_offs + GPC_PGC_PDN_OFFS,
+			   0x1, 0x1);
+
+	/* Request GPC to power down domain */
+	val = BIT(pd->cntr_pdn_bit);
+	regmap_update_bits(pd->regmap, GPC_CNTR, val, val);
+
+	/* Wait ISO + ISO2SW IPG clock cycles */
+	udelay(DIV_ROUND_UP(iso + iso2sw, pd->ipg_rate_mhz));
+
+	if (pd->supply)
+		regulator_disable(pd->supply);
+
+	return 0;
+}
+
+static int imx6_pm_domain_power_on(struct generic_pm_domain *genpd)
+{
+	struct imx_pm_domain *pd = to_imx_pm_domain(genpd);
+	int i, ret, sw, sw2iso;
+	u32 val;
+
+	if (pd->supply) {
+		ret = regulator_enable(pd->supply);
+		if (ret) {
+			pr_err("%s: failed to enable regulator: %d\n",
+			       __func__, ret);
+			return ret;
+		}
+	}
+
+	/* Enable reset clocks for all devices in the domain */
+	for (i = 0; i < pd->num_clks; i++)
+		clk_prepare_enable(pd->clk[i]);
+
+	/* Gate off domain when powered down */
+	regmap_update_bits(pd->regmap, pd->reg_offs + GPC_PGC_PDN_OFFS,
+			   0x1, 0x1);
+
+	/* Read ISO and ISO2SW power down delays */
+	regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val);
+	sw = val & 0x3f;
+	sw2iso = (val >> 8) & 0x3f;
+
+	/* Request GPC to power up domain */
+	val = BIT(pd->cntr_pdn_bit + 1);
+	regmap_update_bits(pd->regmap, GPC_CNTR, val, val);
+
+	/* Wait ISO + ISO2SW IPG clock cycles */
+	udelay(DIV_ROUND_UP(sw + sw2iso, pd->ipg_rate_mhz));
+
+	/* Disable reset clocks for all devices in the domain */
+	for (i = 0; i < pd->num_clks; i++)
+		clk_disable_unprepare(pd->clk[i]);
+
+	return 0;
+}
+
+static int imx_pgc_get_clocks(struct device *dev, struct imx_pm_domain *domain)
+{
+	int i, ret;
+
+	for (i = 0; ; i++) {
+		struct clk *clk = of_clk_get(dev->of_node, i);
+		if (IS_ERR(clk))
+			break;
+		if (i >= GPC_CLK_MAX) {
+			dev_err(dev, "more than %d clocks\n", GPC_CLK_MAX);
+			ret = -EINVAL;
+			goto clk_err;
+		}
+		domain->clk[i] = clk;
+	}
+	domain->num_clks = i;
+
+	return 0;
+
+clk_err:
+	for (; i >= 0; i--)
+		clk_put(domain->clk[i]);
+
+	return ret;
+}
+
+static void imx_pgc_put_clocks(struct imx_pm_domain *domain)
+{
+	int i;
+
+	for (i = domain->num_clks - 1; i >= 0; i--)
+		clk_put(domain->clk[i]);
+}
+
+static int imx_pgc_parse_dt(struct device *dev, struct imx_pm_domain *domain)
+{
+	/* try to get the domain supply regulator */
+	domain->supply = devm_regulator_get_optional(dev, "power");
+	if (IS_ERR(domain->supply)) {
+		if (PTR_ERR(domain->supply) == -ENODEV)
+			domain->supply = NULL;
+		else
+			return PTR_ERR(domain->supply);
+	}
+
+	/* try to get all clocks needed for reset propagation */
+	return imx_pgc_get_clocks(dev, domain);
+}
+
+static int imx_pgc_power_domain_probe(struct platform_device *pdev)
+{
+	struct imx_pm_domain *domain = pdev->dev.platform_data;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	/* if this PD is associated with a DT node try to parse it */
+	if (dev->of_node) {
+		ret = imx_pgc_parse_dt(dev, domain);
+		if (ret)
+			return ret;
+	}
+
+	/* initially power on the domain */
+	if (domain->base.power_on)
+		domain->base.power_on(&domain->base);
+
+	if (IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) {
+		pm_genpd_init(&domain->base, NULL, false);
+		ret = of_genpd_add_provider_simple(dev->of_node, &domain->base);
+		if (ret)
+			goto genpd_err;
+	}
+
+	device_link_add(dev, dev->parent, DL_FLAG_AUTOREMOVE);
+
+	return 0;
+
+genpd_err:
+	pm_genpd_remove(&domain->base);
+	imx_pgc_put_clocks(domain);
+
+	return ret;
+}
+
+static int imx_pgc_power_domain_remove(struct platform_device *pdev)
+{
+	struct imx_pm_domain *domain = pdev->dev.platform_data;
+
+	if (IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) {
+		of_genpd_del_provider(pdev->dev.of_node);
+		pm_genpd_remove(&domain->base);
+		imx_pgc_put_clocks(domain);
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id imx_pgc_power_domain_id[] = {
+	{ "imx-pgc-power-domain"},
+	{ },
+};
+
+static struct platform_driver imx_pgc_power_domain_driver = {
+	.driver = {
+		.name = "imx-pgc-pd",
+	},
+	.probe = imx_pgc_power_domain_probe,
+	.remove = imx_pgc_power_domain_remove,
+	.id_table = imx_pgc_power_domain_id,
+};
+builtin_platform_driver(imx_pgc_power_domain_driver)
+
+static struct genpd_power_state imx6_pm_domain_pu_state = {
+	.power_off_latency_ns = 25000,
+	.power_on_latency_ns = 2000000,
+};
+
+static struct imx_pm_domain imx_gpc_domains[] = {
+	{
+		.base = {
+			.name = "ARM",
+		},
+	}, {
+		.base = {
+			.name = "PU",
+			.power_off = imx6_pm_domain_power_off,
+			.power_on = imx6_pm_domain_power_on,
+			.states = &imx6_pm_domain_pu_state,
+			.state_count = 1,
+		},
+		.reg_offs = 0x260,
+		.cntr_pdn_bit = 0,
+	}, {
+		.base = {
+			.name = "DISPLAY",
+			.power_off = imx6_pm_domain_power_off,
+			.power_on = imx6_pm_domain_power_on,
+		},
+		.reg_offs = 0x240,
+		.cntr_pdn_bit = 4,
+	}
+};
+
+struct imx_gpc_dt_data {
+	int num_domains;
+};
+
+static const struct imx_gpc_dt_data imx6q_dt_data = {
+	.num_domains = 2,
+};
+
+static const struct imx_gpc_dt_data imx6sl_dt_data = {
+	.num_domains = 3,
+};
+
+static const struct of_device_id imx_gpc_dt_ids[] = {
+	{ .compatible = "fsl,imx6q-gpc", .data = &imx6q_dt_data },
+	{ .compatible = "fsl,imx6sl-gpc", .data = &imx6sl_dt_data },
+	{ }
+};
+
+static bool imx_gpc_readable_reg(struct device *dev, unsigned int reg)
+{
+	return (reg % 4 == 0) && (reg <= 0x2ac);
+}
+
+static bool imx_gpc_volatile_reg(struct device *dev, unsigned int reg)
+{
+	if (reg == GPC_CNTR)
+		return true;
+
+	return false;
+}
+
+static const struct regmap_config imx_gpc_regmap_config = {
+	.cache_type = REGCACHE_FLAT,
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+
+	.readable_reg = imx_gpc_readable_reg,
+	.volatile_reg = imx_gpc_volatile_reg,
+
+	.max_register = 0x2ac,
+};
+
+static struct generic_pm_domain *imx_gpc_onecell_domains[] = {
+	&imx_gpc_domains[0].base,
+	&imx_gpc_domains[1].base,
+};
+
+static struct genpd_onecell_data imx_gpc_onecell_data = {
+	.domains = imx_gpc_onecell_domains,
+	.num_domains = 2,
+};
+
+static int imx_gpc_old_dt_init(struct device *dev, struct regmap *regmap)
+{
+	struct imx_pm_domain *domain;
+	int i, ret;
+
+	for (i = 0; i < 2; i++) {
+		domain = &imx_gpc_domains[i];
+		domain->regmap = regmap;
+		domain->ipg_rate_mhz = 66;
+
+		if (i == 1) {
+			domain->supply = devm_regulator_get(dev, "pu");
+			if (IS_ERR(domain->supply))
+				return PTR_ERR(domain->supply);;
+
+			ret = imx_pgc_get_clocks(dev, domain);
+			if (ret)
+				goto clk_err;
+
+			domain->base.power_on(&domain->base);
+		}
+	}
+
+	for (i = 0; i < 2; i++)
+		pm_genpd_init(&imx_gpc_domains[i].base, NULL, false);
+
+	if (IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) {
+		ret = of_genpd_add_provider_onecell(dev->of_node,
+						    &imx_gpc_onecell_data);
+		if (ret)
+			goto genpd_err;
+	}
+
+	return 0;
+
+genpd_err:
+	for (i = 0; i < 2; i++)
+		pm_genpd_remove(&imx_gpc_domains[i].base);
+	imx_pgc_put_clocks(&imx_gpc_domains[1]);
+clk_err:
+	return ret;
+}
+
+static int imx_gpc_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id =
+			of_match_device(imx_gpc_dt_ids, &pdev->dev);
+	const struct imx_gpc_dt_data *of_id_data = of_id->data;
+	struct device_node *pgc_node;
+	struct regmap *regmap;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+
+	pgc_node = of_get_child_by_name(pdev->dev.of_node, "pgc");
+
+	/* bail out if DT too old and doesn't provide the necessary info */
+	if (!of_property_read_bool(pdev->dev.of_node, "#power-domain-cells") &&
+	    !pgc_node)
+		return 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+					   &imx_gpc_regmap_config);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(&pdev->dev, "failed to init regmap: %d\n",
+			ret);
+		return ret;
+	}
+
+	if (!pgc_node) {
+		/* old DT layout is only supported for mx6q aka 2 domains */
+		if (of_id_data->num_domains != 2) {
+			dev_err(&pdev->dev, "could not find pgc DT node\n");
+			return -ENODEV;
+		}
+
+		ret = imx_gpc_old_dt_init(&pdev->dev, regmap);
+		if (ret)
+			return ret;
+	} else {
+		struct imx_pm_domain *domain;
+		struct platform_device *pd_pdev;
+		struct device_node *np;
+		struct clk *ipg_clk;
+		unsigned int ipg_rate_mhz;
+		int domain_index;
+
+		ipg_clk = devm_clk_get(&pdev->dev, "ipg");
+		if (IS_ERR(ipg_clk))
+			return PTR_ERR(ipg_clk);
+		ipg_rate_mhz = clk_get_rate(ipg_clk) / 1000000;
+
+		for_each_child_of_node(pgc_node, np) {
+			ret = of_property_read_u32(np, "reg", &domain_index);
+			if (ret) {
+				of_node_put(np);
+				return ret;
+			}
+			if (domain_index >= ARRAY_SIZE(imx_gpc_domains))
+				continue;
+
+			domain = &imx_gpc_domains[domain_index];
+			domain->regmap = regmap;
+			domain->ipg_rate_mhz = ipg_rate_mhz;
+
+			pd_pdev = platform_device_alloc("imx-pgc-power-domain",
+							domain_index);
+			if (!pd_pdev) {
+				of_node_put(np);
+				return -ENOMEM;
+			}
+			pd_pdev->dev.platform_data = domain;
+			pd_pdev->dev.parent = &pdev->dev;
+			pd_pdev->dev.of_node = np;
+
+			ret = platform_device_add(pd_pdev);
+			if (ret) {
+				platform_device_put(pd_pdev);
+				of_node_put(np);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int imx_gpc_remove(struct platform_device *pdev)
+{
+	int ret;
+
+	/*
+	 * If the old DT binding is used the toplevel driver needs to
+	 * de-register the power domains
+	 */
+	if (!of_get_child_by_name(pdev->dev.of_node, "pgc")) {
+		of_genpd_del_provider(pdev->dev.of_node);
+
+		ret = pm_genpd_remove(&imx_gpc_domains[1].base);
+		if (ret)
+			return ret;
+		imx_pgc_put_clocks(&imx_gpc_domains[1]);
+
+		ret = pm_genpd_remove(&imx_gpc_domains[0].base);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver imx_gpc_driver = {
+	.driver = {
+		.name = "imx-gpc",
+		.of_match_table = imx_gpc_dt_ids,
+	},
+	.probe = imx_gpc_probe,
+	.remove = imx_gpc_remove,
+};
+builtin_platform_driver(imx_gpc_driver)