[PATCH v2 09/18] soc: imx: Add GPCv2 power gating driver

[Andrey Smirnov <andrew.smirnov@gmail.com>]

Port of a Linux commit 03aa12629fc4f73acf28e519c9ee9cb1f5dd3706

  Add code allowing for control of various power domains managed by GPCv2
  IP block found in i.MX7 series of SoCs. Power domains covered by this
  patch are:

      - PCIE PHY
      - MIPI PHY
      - USB HSIC PHY
      - USB OTG1/2 PHY

  Support for any other power domain controlled by GPC is not present, and
  can be added at some later point.

  Testing of this code was done against a PCIe driver.

  Cc: yurovsky@gmail.com
  Cc: Lucas Stach <l.stach@pengutronix.de>
  Cc: Fabio Estevam <fabio.estevam@nxp.com>
  Cc: Dong Aisheng <dongas86@gmail.com>
  Cc: linux-arm-kernel@lists.infradead.org
  Cc: linux-kernel@vger.kernel.org
  Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
  Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Linux commit 9e01e2d56db23485a75864b6aeee8e443f024ddb was squashed
here as well:

  soc: imx: gpcv2: fix regulator deferred probe

  If a regulator requests a deferred probe, the power domain gets
  initialized twice. This leads to a list double add (without
  list debugging the kernel hangs due to the double add later):

    WARNING: CPU: 0 PID: 19 at lib/list_debug.c:31 __list_add_valid+0xbc/0xc4
    list_add double add: new=c1229754, prev=c12383b4, next=c1229754.

  Initialize the power domain after we get the regulator. Also do
  not print an error in case the regulator defers probing.

  Cc: Fabio Estevam <fabio.estevam@nxp.com>
  Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
  Cc: linux-arm-kernel@lists.infradead.org
  Cc: linux-kernel@vger.kernel.org
  Fixes: 03aa12629fc4 ("soc: imx: Add GPCv2 power gating driver")
  Signed-off-by: Stefan Agner <stefan@agner.ch>
  Acked-by: Andrey Smirnov <andrew.smirnov@gmail.com>
  Tested-by: Andrey Smirnov <andrew.smirnov@gmail.com>
  Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Linux commit 3637f12faf507b0a4b8ac1e7115fc99583ab1db3 was squashed
here as well

  soc: imx: gpcv2: correct PGC offset

  Correct MIPI/PCIe/USB_HSIC's PGC offset based on
  design RTL, the values in the Reference Manual
  (Rev. 1, 01/2018 and the older ones) are incorrect.

  The correct offset values should be as below:

  0x800 ~ 0x83F: PGC for core0 of A7 platform;
  0x840 ~ 0x87F: PGC for core1 of A7 platform;
  0x880 ~ 0x8BF: PGC for SCU of A7 platform;
  0xA00 ~ 0xA3F: PGC for fastmix/megamix;
  0xC00 ~ 0xC3F: PGC for MIPI PHY;
  0xC40 ~ 0xC7F: PGC for PCIe_PHY;
  0xC80 ~ 0xCBF: PGC for USB OTG1 PHY;
  0xCC0 ~ 0xCFF: PGC for USB OTG2 PHY;
  0xD00 ~ 0xD3F: PGC for USB HSIC PHY;

  Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
  Fixes: 03aa12629fc4 ("soc: imx: Add GPCv2 power gating driver")
  Acked-by: Andrey Smirnov <andrew.smirnov@gmail.com>
  Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
  Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 drivers/Kconfig          |   1 +
 drivers/Makefile         |   1 +
 drivers/soc/imx/Kconfig  |   9 ++
 drivers/soc/imx/Makefile |   1 +
 drivers/soc/imx/gpcv2.c  | 315 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 327 insertions(+)
 create mode 100644 drivers/soc/imx/Kconfig
 create mode 100644 drivers/soc/imx/Makefile
 create mode 100644 drivers/soc/imx/gpcv2.c

diff --git a/drivers/Kconfig b/drivers/Kconfig
index c3bf9dfe18..c6c2eb14db 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -38,5 +38,6 @@ source "drivers/firmware/Kconfig"
 source "drivers/phy/Kconfig"
 source "drivers/crypto/Kconfig"
 source "drivers/memory/Kconfig"
+source "drivers/soc/imx/Kconfig"
 
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 767789d541..752fd66242 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -38,3 +38,4 @@ obj-$(CONFIG_HAB) += hab/
 obj-$(CONFIG_CRYPTO_HW) += crypto/
 obj-$(CONFIG_AIODEV) += aiodev/
 obj-y	+= memory/
+obj-y	+= soc/imx/
diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
new file mode 100644
index 0000000000..a78a9e3967
--- /dev/null
+++ b/drivers/soc/imx/Kconfig
@@ -0,0 +1,9 @@
+menu "i.MX SoC drivers"
+
+config IMX7_PM_DOMAINS
+	bool "i.MX7 PM domains"
+	depends on ARCH_IMX7
+	select PM_GENERIC_DOMAINS
+	default y if ARCH_IMX7
+
+endmenu
diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
new file mode 100644
index 0000000000..b039f77dc1
--- /dev/null
+++ b/drivers/soc/imx/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
new file mode 100644
index 0000000000..158bfc02de
--- /dev/null
+++ b/drivers/soc/imx/gpcv2.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright 2017 Impinj, Inc
+ * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
+ *
+ * Based on the code of analogus driver:
+ *
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@pengutronix.de>
+ *
+ * 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 <common.h>
+#include <clock.h>
+#include <abort.h>
+#include <malloc.h>
+#include <io.h>
+#include <init.h>
+#include <linux/iopoll.h>
+
+#include <pm_domain.h>
+#include <regulator.h>
+#include <dt-bindings/power/imx7-power.h>
+
+#define GPC_LPCR_A7_BSC			0x000
+
+#define GPC_PGC_CPU_MAPPING		0x0ec
+#define USB_HSIC_PHY_A7_DOMAIN		BIT(6)
+#define USB_OTG2_PHY_A7_DOMAIN		BIT(5)
+#define USB_OTG1_PHY_A7_DOMAIN		BIT(4)
+#define PCIE_PHY_A7_DOMAIN		BIT(3)
+#define MIPI_PHY_A7_DOMAIN		BIT(2)
+
+#define GPC_PU_PGC_SW_PUP_REQ		0x0f8
+#define GPC_PU_PGC_SW_PDN_REQ		0x104
+#define USB_HSIC_PHY_SW_Pxx_REQ		BIT(4)
+#define USB_OTG2_PHY_SW_Pxx_REQ		BIT(3)
+#define USB_OTG1_PHY_SW_Pxx_REQ		BIT(2)
+#define PCIE_PHY_SW_Pxx_REQ		BIT(1)
+#define MIPI_PHY_SW_Pxx_REQ		BIT(0)
+
+#define GPC_M4_PU_PDN_FLG		0x1bc
+
+/*
+ * The PGC offset values in Reference Manual
+ * (Rev. 1, 01/2018 and the older ones) GPC chapter's
+ * GPC_PGC memory map are incorrect, below offset
+ * values are from design RTL.
+ */
+#define PGC_MIPI                       16
+#define PGC_PCIE                       17
+#define PGC_USB_HSIC                   20
+#define GPC_PGC_CTRL(n)			(0x800 + (n) * 0x40)
+#define GPC_PGC_SR(n)			(GPC_PGC_CTRL(n) + 0xc)
+
+#define GPC_PGC_CTRL_PCR		BIT(0)
+
+struct imx7_pgc_domain {
+	struct generic_pm_domain genpd;
+	void __iomem *base;
+	struct regulator *regulator;
+
+	unsigned int pgc;
+
+	const struct {
+		u32 pxx;
+		u32 map;
+	} bits;
+
+	const int voltage;
+	struct device_d *dev;
+};
+
+static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
+				      bool on)
+{
+	struct imx7_pgc_domain *domain = container_of(genpd,
+						      struct imx7_pgc_domain,
+						      genpd);
+	unsigned int offset = on ?
+		GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
+	const bool enable_power_control = !on;
+	const bool has_regulator = !IS_ERR(domain->regulator);
+	int ret = 0;
+	unsigned int mapping, ctrl = 0, pxx;
+
+	mapping = readl(domain->base + GPC_PGC_CPU_MAPPING);
+	mapping |= domain->bits.map;
+	writel(mapping, domain->base + GPC_PGC_CPU_MAPPING);
+
+	if (has_regulator && on) {
+		ret = regulator_enable(domain->regulator);
+		if (ret) {
+			dev_err(domain->dev, "failed to enable regulator\n");
+			goto unmap;
+		}
+	}
+
+	if (enable_power_control) {
+		ctrl = readl(domain->base + GPC_PGC_CTRL(domain->pgc));
+		ctrl |= GPC_PGC_CTRL_PCR;
+		writel(ctrl, domain->base + GPC_PGC_CTRL(domain->pgc));
+	}
+
+	pxx = readl(domain->base + offset);
+	pxx |= domain->bits.pxx;
+	writel(pxx, domain->base + offset);
+
+	/*
+	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+	 * for PUP_REQ/PDN_REQ bit to be cleared
+	 */
+	ret = readl_poll_timeout(domain->base + offset, pxx,
+				 !(pxx & domain->bits.pxx), MSECOND);
+	if (ret < 0) {
+		dev_err(domain->dev, "falied to command PGC\n");
+		/*
+		 * If we were in a process of enabling a
+		 * domain and failed we might as well disable
+		 * the regulator we just enabled. And if it
+		 * was the opposite situation and we failed to
+		 * power down -- keep the regulator on
+		 */
+		on = !on;
+	}
+
+	if (enable_power_control) {
+		ctrl &= ~GPC_PGC_CTRL_PCR;
+		writel(ctrl, domain->base + GPC_PGC_CTRL(domain->pgc));
+	}
+
+	if (has_regulator && !on) {
+		int err;
+
+		err = regulator_disable(domain->regulator);
+		if (err)
+			dev_err(domain->dev,
+				"failed to disable regulator: %d\n", ret);
+		/* Preserve earlier error code */
+		ret = ret ?: err;
+	}
+unmap:
+	mapping &= ~domain->bits.map;
+	writel(mapping, domain->base + GPC_PGC_CPU_MAPPING);
+
+	return ret;
+}
+
+static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
+}
+
+static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
+}
+
+static const struct imx7_pgc_domain imx7_pgc_domains[] = {
+	[IMX7_POWER_DOMAIN_MIPI_PHY] = {
+		.genpd = {
+			.name      = "mipi-phy",
+		},
+		.bits  = {
+			.pxx = MIPI_PHY_SW_Pxx_REQ,
+			.map = MIPI_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc	   = PGC_MIPI,
+	},
+
+	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
+		.genpd = {
+			.name      = "pcie-phy",
+		},
+		.bits  = {
+			.pxx = PCIE_PHY_SW_Pxx_REQ,
+			.map = PCIE_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc	   = PGC_PCIE,
+	},
+
+	[IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
+		.genpd = {
+			.name      = "usb-hsic-phy",
+		},
+		.bits  = {
+			.pxx = USB_HSIC_PHY_SW_Pxx_REQ,
+			.map = USB_HSIC_PHY_A7_DOMAIN,
+	},
+		.voltage   = 1200000,
+		.pgc	   = PGC_USB_HSIC,
+	},
+};
+
+static int imx7_pgc_domain_probe(struct device_d *dev)
+{
+	struct imx7_pgc_domain *domain = dev->priv;
+	int ret;
+
+	domain->dev = dev;
+
+	domain->regulator = regulator_get(domain->dev, "power");
+	if (IS_ERR(domain->regulator)) {
+		if (PTR_ERR(domain->regulator) != -ENODEV) {
+			if (PTR_ERR(domain->regulator) != -EPROBE_DEFER)
+				dev_err(domain->dev, "Failed to get domain's regulator\n");
+			return PTR_ERR(domain->regulator);
+		}
+	} else {
+		regulator_set_voltage(domain->regulator,
+				      domain->voltage, domain->voltage);
+	}
+
+	ret = pm_genpd_init(&domain->genpd, NULL, true);
+	if (ret) {
+		dev_err(domain->dev, "Failed to init power domain\n");
+		return ret;
+	}
+
+	ret = of_genpd_add_provider_simple(domain->dev->device_node,
+					   &domain->genpd);
+	if (ret) {
+		dev_err(domain->dev, "Failed to add genpd provider\n");
+	}
+
+	return ret;
+}
+
+static const struct platform_device_id imx7_pgc_domain_id[] = {
+	{ "imx7-pgc-domain", },
+	{ },
+};
+
+static struct driver_d imx7_pgc_domain_driver = {
+	.name = "imx-pgc",
+	.probe = imx7_pgc_domain_probe,
+	.id_table = imx7_pgc_domain_id,
+};
+coredevice_platform_driver(imx7_pgc_domain_driver);
+
+static int imx_gpcv2_probe(struct device_d *dev)
+{
+	struct device_node *pgc_np, *np;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+
+	pgc_np = of_get_child_by_name(dev->device_node, "pgc");
+	if (!pgc_np) {
+		dev_err(dev, "No power domains specified in DT\n");
+		return -EINVAL;
+	}
+
+	res = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	base = IOMEM(res->start);
+
+	for_each_child_of_node(pgc_np, np) {
+		struct device_d *pd_dev;
+		struct imx7_pgc_domain *domain;
+		u32 domain_index;
+		ret = of_property_read_u32(np, "reg", &domain_index);
+		if (ret) {
+			dev_err(dev, "Failed to read 'reg' property\n");
+			return ret;
+		}
+
+		if (domain_index >= ARRAY_SIZE(imx7_pgc_domains)) {
+			dev_warn(dev,
+				 "Domain index %d is out of bounds\n",
+				 domain_index);
+			continue;
+		}
+
+		domain = xmemdup(&imx7_pgc_domains[domain_index],
+				 sizeof(imx7_pgc_domains[domain_index]));
+		domain->base = base;
+		domain->genpd.power_on = imx7_gpc_pu_pgc_sw_pup_req;
+		domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
+
+		pd_dev = xzalloc(sizeof(*pd_dev));
+		pd_dev->device_node = np;
+		pd_dev->id = domain_index;
+		pd_dev->parent = dev;
+		pd_dev->priv = domain;
+		pd_dev->device_node = np;
+		dev_set_name(pd_dev, imx7_pgc_domain_id[0].name);
+
+		ret = platform_device_register(pd_dev);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id imx_gpcv2_dt_ids[] = {
+	{ .compatible = "fsl,imx7d-gpc" },
+	{ }
+};
+
+static struct driver_d imx_gpcv2_driver = {
+	.name = "imx7d-gpc",
+	.probe = imx_gpcv2_probe,
+	.of_compatible = DRV_OF_COMPAT(imx_gpcv2_dt_ids),
+};
+coredevice_platform_driver(imx_gpcv2_driver);
-- 
2.20.1


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