[PATCH V9 5/5] firmware: imx: add SCU power domain driver

["A.s. Dong" <aisheng.dong@nxp.com>]

Some i.MX SoCs contain a system controller that is responsible for
controlling the state of the IPs that are present. Communication
between the host processor running an OS and the system controller
happens through a SCU protocol. This patch adds SCU protocol based
power domains drivers.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
ChangeLog:
v8->v9:
 * add comment at the top of scu-pd.c file about how to convert
   to "single global domain".
v7->v8:
 * update to #power-domain-cells 1 binding
v6->v7:
 * still using generic "fsl,scu-pd" to driver binding incase the future
   SoC is compatible
 * remove unnecessary cast
v5->v6:
 * only compatible string name updated from fsl,scu-pd to fsl,imx8qxp-scu-pd
   accordingly
v4->v5:
 * minor improvements according to Sascha's suggestions
v3->v4:
 * update firmware headfile patch from include/soc/imx to
   include/linux/firmware/imx
v2->v3:
 * name of structures/enums updated with imx_sc prefix
v1->v2:
 * move into drivers/firmware/imx
 * Implement sc_pm_set_resource_power_mode() API in the driver instead
   of call it via SCU API according to Sascha's suggestion
---
 drivers/firmware/imx/Kconfig  |   6 +
 drivers/firmware/imx/Makefile |   3 +-
 drivers/firmware/imx/scu-pd.c | 339 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 347 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/imx/scu-pd.c

diff --git a/drivers/firmware/imx/Kconfig b/drivers/firmware/imx/Kconfig
index b170c28..6a7a7c2 100644
--- a/drivers/firmware/imx/Kconfig
+++ b/drivers/firmware/imx/Kconfig
@@ -9,3 +9,9 @@ config IMX_SCU
 
 	  This driver manages the IPC interface between host CPU and the
 	  SCU firmware running on M4.
+
+config IMX_SCU_PD
+	bool "IMX SCU Power Domain driver"
+	depends on IMX_SCU
+	help
+	  The System Controller Firmware (SCFW) based power domain driver.
diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
index 0ac04df..1b2e15b 100644
--- a/drivers/firmware/imx/Makefile
+++ b/drivers/firmware/imx/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_IMX_SCU)	+= imx-scu.o misc.o
+obj-$(CONFIG_IMX_SCU)		+= imx-scu.o misc.o
+obj-$(CONFIG_IMX_SCU_PD)	+= scu-pd.o
diff --git a/drivers/firmware/imx/scu-pd.c b/drivers/firmware/imx/scu-pd.c
new file mode 100644
index 0000000..407245f
--- /dev/null
+++ b/drivers/firmware/imx/scu-pd.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP
+ *	Dong Aisheng <aisheng.dong@nxp.com>
+ *
+ * Implementation of the SCU based Power Domains
+ *
+ * NOTE: a better implementation suggested by Ulf Hansson is using a
+ * single global power domain and implement the ->attach|detach_dev()
+ * callback for the genpd and use the regular of_genpd_add_provider_simple().
+ * From within the ->attach_dev(), we could get the OF node for
+ * the device that is being attached and then parse the power-domain
+ * cell containing the "resource id" and store that in the per device
+ * struct generic_pm_domain_data (we have void pointer there for
+ * storing these kind of things).
+ *
+ * Additionally, we need to implement the ->stop() and ->start()
+ * callbacks of genpd, which is where you "power on/off" devices,
+ * rather than using the above ->power_on|off() callbacks.
+ *
+ * However, there're two known issues:
+ * 1. The ->attach_dev() of power domain infrastructure still does
+ *    not support multi domains case as the struct device *dev passed
+ *    in is a virtual PD device, it does not help for parsing the real
+ *    device resource id from device tree, so it's unware of which
+ *    real sub power domain of device should be attached.
+ *
+ *    The framework needs some proper extension to support multi power
+ *    domain cases.
+ *
+ * 2. It also breaks most of current drivers as the driver probe sequence
+ *    behavior changed if removing ->power_on|off() callback and use
+ *    ->start() and ->stop() instead. genpd_dev_pm_attach will only power
+ *    up the domain and attach device, but will not call .start() which
+ *    relies on device runtime pm. That means the device power is still
+ *    not up before running driver probe function. For SCU enabled
+ *    platforms, all device drivers accessing registers/clock without power
+ *    domain enabled will trigger a HW access error. That means we need fix
+ *    most drivers probe sequence with proper runtime pm.
+ *
+ * In summary, we need fix above two issue before being able to switch to
+ * the "single global power domain" way.
+ *
+ */
+
+#include <dt-bindings/firmware/imx/rsrc.h>
+#include <linux/firmware/imx/sci.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_domain.h>
+#include <linux/slab.h>
+
+/* SCU Power Mode Protocol definition */
+struct imx_sc_msg_req_set_resource_power_mode {
+	struct imx_sc_rpc_msg hdr;
+	u16 resource;
+	u8 mode;
+} __packed;
+
+#define IMX_SCU_PD_NAME_SIZE 20
+struct imx_sc_pm_domain {
+	struct generic_pm_domain pd;
+	char name[IMX_SCU_PD_NAME_SIZE];
+	u32 rsrc;
+};
+
+struct imx_sc_pd_range {
+	char *name;
+	u32 rsrc;
+	u8 num;
+	bool postfix;
+};
+
+struct imx_sc_pd_soc {
+	const struct imx_sc_pd_range *pd_ranges;
+	u8 num_ranges;
+};
+
+static const struct imx_sc_pd_range imx8qxp_scu_pd_ranges[] = {
+	/* LSIO SS */
+	{ "lsio-pwm", IMX_SC_R_PWM_0, 8, 1 },
+	{ "lsio-gpio", IMX_SC_R_GPIO_0, 8, 1 },
+	{ "lsio-gpt", IMX_SC_R_GPT_0, 5, 1 },
+	{ "lsio-kpp", IMX_SC_R_KPP, 1, 0 },
+	{ "lsio-fspi", IMX_SC_R_FSPI_0, 2, 1 },
+	{ "lsio-mu", IMX_SC_R_MU_0A, 14, 1 },
+
+	/* CONN SS */
+	{ "con-usb", IMX_SC_R_USB_0, 2, 1 },
+	{ "con-usb0phy", IMX_SC_R_USB_0_PHY, 1, 0 },
+	{ "con-usb2", IMX_SC_R_USB_2, 1, 0 },
+	{ "con-usb2phy", IMX_SC_R_USB_2_PHY, 1, 0 },
+	{ "con-sdhc", IMX_SC_R_SDHC_0, 3, 1 },
+	{ "con-enet", IMX_SC_R_ENET_0, 2, 1 },
+	{ "con-nand", IMX_SC_R_NAND, 1, 0 },
+	{ "con-mlb", IMX_SC_R_MLB_0, 1, 1 },
+
+	/* Audio DMA SS */
+	{ "adma-audio-pll0", IMX_SC_R_AUDIO_PLL_0, 1, 0 },
+	{ "adma-audio-pll1", IMX_SC_R_AUDIO_PLL_1, 1, 0 },
+	{ "adma-audio-clk-0", IMX_SC_R_AUDIO_CLK_0, 1, 0 },
+	{ "adma-dma0-ch", IMX_SC_R_DMA_0_CH0, 16, 1 },
+	{ "adma-dma1-ch", IMX_SC_R_DMA_1_CH0, 16, 1 },
+	{ "adma-dma2-ch", IMX_SC_R_DMA_2_CH0, 5, 1 },
+	{ "adma-asrc0", IMX_SC_R_ASRC_0, 1, 0 },
+	{ "adma-asrc1", IMX_SC_R_ASRC_1, 1, 0 },
+	{ "adma-esai0", IMX_SC_R_ESAI_0, 1, 0 },
+	{ "adma-spdif0", IMX_SC_R_SPDIF_0, 1, 0 },
+	{ "adma-sai", IMX_SC_R_SAI_0, 3, 1 },
+	{ "adma-amix", IMX_SC_R_AMIX, 1, 0 },
+	{ "adma-mqs0", IMX_SC_R_MQS_0, 1, 0 },
+	{ "adma-dsp", IMX_SC_R_DSP, 1, 0 },
+	{ "adma-dsp-ram", IMX_SC_R_DSP_RAM, 1, 0 },
+	{ "adma-can", IMX_SC_R_CAN_0, 3, 1 },
+	{ "adma-ftm", IMX_SC_R_FTM_0, 2, 1 },
+	{ "adma-lpi2c", IMX_SC_R_I2C_0, 4, 1 },
+	{ "adma-adc", IMX_SC_R_ADC_0, 1, 1 },
+	{ "adma-lcd", IMX_SC_R_LCD_0, 1, 1 },
+	{ "adma-lcd0-pwm", IMX_SC_R_LCD_0_PWM_0, 1, 1 },
+	{ "adma-lpuart", IMX_SC_R_UART_0, 4, 1 },
+	{ "adma-lpspi", IMX_SC_R_SPI_0, 4, 1 },
+
+	/* VPU SS  */
+	{ "vpu", IMX_SC_R_VPU, 1, 0 },
+	{ "vpu-pid", IMX_SC_R_VPU_PID0, 8, 1 },
+	{ "vpu-dec0", IMX_SC_R_VPU_DEC_0, 1, 0 },
+	{ "vpu-enc0", IMX_SC_R_VPU_ENC_0, 1, 0 },
+
+	/* GPU SS */
+	{ "gpu0-pid", IMX_SC_R_GPU_0_PID0, 4, 1 },
+
+	/* HSIO SS */
+	{ "hsio-pcie-b", IMX_SC_R_PCIE_B, 1, 0 },
+	{ "hsio-serdes-1", IMX_SC_R_SERDES_1, 1, 0 },
+	{ "hsio-gpio", IMX_SC_R_HSIO_GPIO, 1, 0 },
+
+	/* MIPI/LVDS SS */
+	{ "mipi0", IMX_SC_R_MIPI_0, 1, 0 },
+	{ "mipi0-pwm0", IMX_SC_R_MIPI_0_PWM_0, 1, 0 },
+	{ "mipi0-i2c", IMX_SC_R_MIPI_0_I2C_0, 2, 1 },
+	{ "lvds0", IMX_SC_R_LVDS_0, 1, 0 },
+
+	/* DC SS */
+	{ "dc0", IMX_SC_R_DC_0, 1, 0 },
+	{ "dc0-pll", IMX_SC_R_DC_0_PLL_0, 2, 1 },
+};
+
+static const struct imx_sc_pd_soc imx8qxp_scu_pd = {
+	.pd_ranges = imx8qxp_scu_pd_ranges,
+	.num_ranges = ARRAY_SIZE(imx8qxp_scu_pd_ranges),
+};
+
+static struct imx_sc_ipc *pm_ipc_handle;
+
+static inline struct imx_sc_pm_domain *
+to_imx_sc_pd(struct generic_pm_domain *genpd)
+{
+	return container_of(genpd, struct imx_sc_pm_domain, pd);
+}
+
+static int imx_sc_pd_power(struct generic_pm_domain *domain, bool power_on)
+{
+	struct imx_sc_msg_req_set_resource_power_mode msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	struct imx_sc_pm_domain *pd;
+	int ret;
+
+	pd = to_imx_sc_pd(domain);
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_PM;
+	hdr->func = IMX_SC_PM_FUNC_SET_RESOURCE_POWER_MODE;
+	hdr->size = 2;
+
+	msg.resource = pd->rsrc;
+	msg.mode = power_on ? IMX_SC_PM_PW_MODE_ON : IMX_SC_PM_PW_MODE_LP;
+
+	ret = imx_scu_call_rpc(pm_ipc_handle, &msg, true);
+	if (ret)
+		dev_err(&domain->dev, "failed to power %s resource %d ret %d\n",
+			power_on ? "up" : "off", pd->rsrc, ret);
+
+	return ret;
+}
+
+static int imx_sc_pd_power_on(struct generic_pm_domain *domain)
+{
+	return imx_sc_pd_power(domain, true);
+}
+
+static int imx_sc_pd_power_off(struct generic_pm_domain *domain)
+{
+	return imx_sc_pd_power(domain, false);
+}
+
+static struct generic_pm_domain *imx_scu_pd_xlate(struct of_phandle_args *spec,
+						  void *data)
+{
+	struct generic_pm_domain *domain = ERR_PTR(-ENOENT);
+	struct genpd_onecell_data *pd_data = data;
+	unsigned int i;
+
+	for (i = 0; i < pd_data->num_domains; i++) {
+		struct imx_sc_pm_domain *sc_pd;
+
+		sc_pd = to_imx_sc_pd(pd_data->domains[i]);
+		if (sc_pd->rsrc == spec->args[0]) {
+			domain = &sc_pd->pd;
+			break;
+		}
+	}
+
+	return domain;
+}
+
+static struct imx_sc_pm_domain *
+imx_scu_add_pm_domain(struct device *dev, int idx,
+		      const struct imx_sc_pd_range *pd_ranges)
+{
+	struct imx_sc_pm_domain *sc_pd;
+	int ret;
+
+	sc_pd = devm_kzalloc(dev, sizeof(*sc_pd), GFP_KERNEL);
+	if (!sc_pd)
+		return ERR_PTR(-ENOMEM);
+
+	sc_pd->rsrc = pd_ranges->rsrc + idx;
+	sc_pd->pd.power_off = imx_sc_pd_power_off;
+	sc_pd->pd.power_on = imx_sc_pd_power_on;
+
+	if (pd_ranges->postfix)
+		snprintf(sc_pd->name, sizeof(sc_pd->name),
+			 "%s%i", pd_ranges->name, idx);
+	else
+		snprintf(sc_pd->name, sizeof(sc_pd->name),
+			 "%s", pd_ranges->name);
+
+	sc_pd->pd.name = sc_pd->name;
+
+	if (sc_pd->rsrc >= IMX_SC_R_LAST) {
+		dev_warn(dev, "invalid pd %s rsrc id %d found",
+			 sc_pd->name, sc_pd->rsrc);
+
+		devm_kfree(dev, sc_pd);
+		return NULL;
+	}
+
+	ret = pm_genpd_init(&sc_pd->pd, NULL, true);
+	if (ret) {
+		dev_warn(dev, "failed to init pd %s rsrc id %d",
+			 sc_pd->name, sc_pd->rsrc);
+		devm_kfree(dev, sc_pd);
+		return NULL;
+	}
+
+	return sc_pd;
+}
+
+static int imx_scu_init_pm_domains(struct device *dev,
+				    const struct imx_sc_pd_soc *pd_soc)
+{
+	const struct imx_sc_pd_range *pd_ranges = pd_soc->pd_ranges;
+	struct generic_pm_domain **domains;
+	struct genpd_onecell_data *pd_data;
+	struct imx_sc_pm_domain *sc_pd;
+	u32 count = 0;
+	int i, j;
+
+	for (i = 0; i < pd_soc->num_ranges; i++)
+		count += pd_ranges[i].num;
+
+	domains = devm_kcalloc(dev, count, sizeof(*domains), GFP_KERNEL);
+	if (!domains)
+		return -ENOMEM;
+
+	pd_data = devm_kzalloc(dev, sizeof(*pd_data), GFP_KERNEL);
+	if (!pd_data)
+		return -ENOMEM;
+
+	count = 0;
+	for (i = 0; i < pd_soc->num_ranges; i++) {
+		for (j = 0; j < pd_ranges[i].num; j++) {
+			sc_pd = imx_scu_add_pm_domain(dev, j, &pd_ranges[i]);
+			if (IS_ERR_OR_NULL(sc_pd))
+				continue;
+
+			domains[count++] = &sc_pd->pd;
+			dev_dbg(dev, "added power domain %s\n", sc_pd->pd.name);
+		}
+	}
+
+	pd_data->domains = domains;
+	pd_data->num_domains = count;
+	pd_data->xlate = imx_scu_pd_xlate;
+
+	of_genpd_add_provider_onecell(dev->of_node, pd_data);
+
+	return 0;
+}
+
+static int imx_sc_pd_probe(struct platform_device *pdev)
+{
+	const struct imx_sc_pd_soc *pd_soc;
+	int ret;
+
+	ret = imx_scu_get_handle(&pm_ipc_handle);
+	if (ret)
+		return ret;
+
+	pd_soc = of_device_get_match_data(&pdev->dev);
+	if (!pd_soc)
+		return -ENODEV;
+
+	return imx_scu_init_pm_domains(&pdev->dev, pd_soc);
+}
+
+static const struct of_device_id imx_sc_pd_match[] = {
+	{ .compatible = "fsl,imx8qxp-scu-pd", &imx8qxp_scu_pd},
+	{ /* sentinel */ }
+};
+
+static struct platform_driver imx_sc_pd_driver = {
+	.driver = {
+		.name = "imx-scu-pd",
+		.of_match_table = imx_sc_pd_match,
+	},
+	.probe = imx_sc_pd_probe,
+};
+builtin_platform_driver(imx_sc_pd_driver);
+
+MODULE_AUTHOR("Dong Aisheng <aisheng.dong@nxp.com>");
+MODULE_DESCRIPTION("IMX SCU Power Domain driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4