ARM: imx6: gpc: Add PU power domain for GPU/VPU

When generic pm domain support is enabled, the PGC can be used
to completely gate power to the PU power domain containing GPU3D,
GPU2D, and VPU cores.
This code triggers the PGC powerdown sequence to disable the GPU/VPU
isolation cells and gate power and then disables the PU regulator.
To reenable, the reverse powerup sequence is triggered after the PU
regulator is enabled again.
The GPU and VPU devices in the PU power domain temporarily need
to be clocked during powerup, so that the reset machinery can work.

[Avoid explicit regulator enabling in probe, unless !PM]
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/Kconfig

@@ -50,6 +50,7 @@ config HAVE_IMX_ANATOP
 
 config HAVE_IMX_GPC
 	bool
+	select PM_GENERIC_DOMAINS if PM
 
 config HAVE_IMX_MMDC
 	bool

arch/arm/mach-imx/gpc.c

@@ -10,15 +10,25 @@
  * http://www.gnu.org/copyleft/gpl.html
  */
 
+#include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regulator/consumer.h>
 #include <linux/irqchip/arm-gic.h>
 #include "common.h"
+#include "hardware.h"
 
+#define GPC_CNTR		0x000
 #define GPC_IMR1		0x008
+#define GPC_PGC_GPU_PDN		0x260
+#define GPC_PGC_GPU_PUPSCR	0x264
+#define GPC_PGC_GPU_PDNSCR	0x268
 #define GPC_PGC_CPU_PDN		0x2a0
 #define GPC_PGC_CPU_PUPSCR	0x2a4
 #define GPC_PGC_CPU_PDNSCR	0x2a8
@@ -27,6 +37,18 @@
 
 #define IMR_NUM			4
 
+#define GPU_VPU_PUP_REQ		BIT(1)
+#define GPU_VPU_PDN_REQ		BIT(0)
+
+#define GPC_CLK_MAX		6
+
+struct pu_domain {
+	struct generic_pm_domain base;
+	struct regulator *reg;
+	struct clk *clk[GPC_CLK_MAX];
+	int num_clks;
+};
+
 static void __iomem *gpc_base;
 static u32 gpc_wake_irqs[IMR_NUM];
 static u32 gpc_saved_imrs[IMR_NUM];
@@ -170,3 +192,194 @@ void __init imx_gpc_init(void)
 	gic_arch_extn.irq_unmask = imx_gpc_irq_unmask;
 	gic_arch_extn.irq_set_wake = imx_gpc_irq_set_wake;
 }
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+
+static void _imx6q_pm_pu_power_off(struct generic_pm_domain *genpd)
+{
+	int iso, iso2sw;
+	u32 val;
+
+	/* Read ISO and ISO2SW power down delays */
+	val = readl_relaxed(gpc_base + GPC_PGC_GPU_PDNSCR);
+	iso = val & 0x3f;
+	iso2sw = (val >> 8) & 0x3f;
+
+	/* Gate off PU domain when GPU/VPU when powered down */
+	writel_relaxed(0x1, gpc_base + GPC_PGC_GPU_PDN);
+
+	/* Request GPC to power down GPU/VPU */
+	val = readl_relaxed(gpc_base + GPC_CNTR);
+	val |= GPU_VPU_PDN_REQ;
+	writel_relaxed(val, gpc_base + GPC_CNTR);
+
+	/* Wait ISO + ISO2SW IPG clock cycles */
+	ndelay((iso + iso2sw) * 1000 / 66);
+}
+
+static int imx6q_pm_pu_power_off(struct generic_pm_domain *genpd)
+{
+	struct pu_domain *pu = container_of(genpd, struct pu_domain, base);
+
+	_imx6q_pm_pu_power_off(genpd);
+
+	if (pu->reg)
+		regulator_disable(pu->reg);
+
+	return 0;
+}
+
+static int imx6q_pm_pu_power_on(struct generic_pm_domain *genpd)
+{
+	struct pu_domain *pu = container_of(genpd, struct pu_domain, base);
+	int i, ret, sw, sw2iso;
+	u32 val;
+
+	if (pu->reg)
+		ret = regulator_enable(pu->reg);
+	if (pu->reg && ret) {
+		pr_err("%s: failed to enable regulator: %d\n", __func__, ret);
+		return ret;
+	}
+
+	/* Enable reset clocks for all devices in the PU domain */
+	for (i = 0; i < pu->num_clks; i++)
+		clk_prepare_enable(pu->clk[i]);
+
+	/* Gate off PU domain when GPU/VPU when powered down */
+	writel_relaxed(0x1, gpc_base + GPC_PGC_GPU_PDN);
+
+	/* Read ISO and ISO2SW power down delays */
+	val = readl_relaxed(gpc_base + GPC_PGC_GPU_PUPSCR);
+	sw = val & 0x3f;
+	sw2iso = (val >> 8) & 0x3f;
+
+	/* Request GPC to power up GPU/VPU */
+	val = readl_relaxed(gpc_base + GPC_CNTR);
+	val |= GPU_VPU_PUP_REQ;
+	writel_relaxed(val, gpc_base + GPC_CNTR);
+
+	/* Wait ISO + ISO2SW IPG clock cycles */
+	ndelay((sw + sw2iso) * 1000 / 66);
+
+	/* Disable reset clocks for all devices in the PU domain */
+	for (i = 0; i < pu->num_clks; i++)
+		clk_disable_unprepare(pu->clk[i]);
+
+	return 0;
+}
+
+static struct generic_pm_domain imx6q_arm_domain = {
+	.name = "ARM",
+};
+
+static struct pu_domain imx6q_pu_domain = {
+	.base = {
+		.name = "PU",
+		.power_off = imx6q_pm_pu_power_off,
+		.power_on = imx6q_pm_pu_power_on,
+		.power_off_latency_ns = 25000,
+		.power_on_latency_ns = 2000000,
+	},
+};
+
+static struct generic_pm_domain imx6sl_display_domain = {
+	.name = "DISPLAY",
+};
+
+static struct generic_pm_domain *imx_gpc_domains[] = {
+	&imx6q_arm_domain,
+	&imx6q_pu_domain.base,
+	&imx6sl_display_domain,
+};
+
+static struct genpd_onecell_data imx_gpc_onecell_data = {
+	.domains = imx_gpc_domains,
+	.num_domains = ARRAY_SIZE(imx_gpc_domains),
+};
+
+static int imx_gpc_genpd_init(struct device *dev, struct regulator *pu_reg)
+{
+	struct clk *clk;
+	bool is_off;
+	int i;
+
+	imx6q_pu_domain.reg = pu_reg;
+
+	for (i = 0; ; i++) {
+		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);
+			goto clk_err;
+		}
+		imx6q_pu_domain.clk[i] = clk;
+	}
+	imx6q_pu_domain.num_clks = i;
+
+	is_off = IS_ENABLED(CONFIG_PM);
+	if (is_off) {
+		_imx6q_pm_pu_power_off(&imx6q_pu_domain.base);
+	} else {
+		/*
+		 * Enable power if compiled without CONFIG_PM in case the
+		 * bootloader disabled it.
+		 */
+		imx6q_pm_pu_power_on(&imx6q_pu_domain.base);
+	}
+
+	pm_genpd_init(&imx6q_pu_domain.base, NULL, is_off);
+	return of_genpd_add_provider_onecell(dev->of_node,
+					     &imx_gpc_onecell_data);
+
+clk_err:
+	while (i--)
+		clk_put(imx6q_pu_domain.clk[i]);
+	return -EINVAL;
+}
+
+#else
+static inline int imx_gpc_genpd_init(struct device *dev, struct regulator *reg)
+{
+	return 0;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS */
+
+static int imx_gpc_probe(struct platform_device *pdev)
+{
+	struct regulator *pu_reg;
+	int ret;
+
+	pu_reg = devm_regulator_get_optional(&pdev->dev, "pu");
+	if (PTR_ERR(pu_reg) == -ENODEV)
+		pu_reg = NULL;
+	if (IS_ERR(pu_reg)) {
+		ret = PTR_ERR(pu_reg);
+		dev_err(&pdev->dev, "failed to get pu regulator: %d\n", ret);
+		return ret;
+	}
+
+	return imx_gpc_genpd_init(&pdev->dev, pu_reg);
+}
+
+static const struct of_device_id imx_gpc_dt_ids[] = {
+	{ .compatible = "fsl,imx6q-gpc" },
+	{ .compatible = "fsl,imx6sl-gpc" },
+	{ }
+};
+
+static struct platform_driver imx_gpc_driver = {
+	.driver = {
+		.name = "imx-gpc",
+		.owner = THIS_MODULE,
+		.of_match_table = imx_gpc_dt_ids,
+	},
+	.probe = imx_gpc_probe,
+};
+
+static int __init imx_pgc_init(void)
+{
+	return platform_driver_register(&imx_gpc_driver);
+}
+subsys_initcall(imx_pgc_init);