soc: Mediatek: Add SCPSYS power domain driver

This adds a power domain driver for the Mediatek SCPSYS unit.

The System Control Processor System (SCPSYS) has several power
management related tasks in the system. The tasks include thermal
measurement, dynamic voltage frequency scaling (DVFS), interrupt
filter and lowlevel sleep control. The System Power Manager (SPM)
inside the SCPSYS is for the MTCMOS power domain control.

For now this driver only adds power domain support, the more
advanced features are not yet supported. The driver implements
the generic PM domain device tree bindings, the first user will
most likely be the Mediatek AFE audio driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

3 files changed, 498 insertions, 0 deletions

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
index e609a6f5e2eb..9d5068248aa0 100644
--- a/drivers/soc/mediatek/Kconfig
+++ b/drivers/soc/mediatek/Kconfig
@@ -19,3 +19,13 @@ config MTK_PMIC_WRAP
 	  Say yes here to add support for MediaTek PMIC Wrapper found
 	  on different MediaTek SoCs. The PMIC wrapper is a proprietary
 	  hardware to connect the PMIC.
+
+config MTK_SCPSYS
+	bool "MediaTek SCPSYS Support"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select REGMAP
+	select MTK_INFRACFG
+	select PM_GENERIC_DOMAINS if PM
+	help
+	  Say yes here to add support for the MediaTek SCPSYS power domain
+	  driver.
diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
index 3fa940fb4eab..12998b08819e 100644
--- a/drivers/soc/mediatek/Makefile
+++ b/drivers/soc/mediatek/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
 obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
+obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
new file mode 100644
index 000000000000..43a79ed761c4
--- /dev/null
+++ b/drivers/soc/mediatek/mtk-scpsys.c
@@ -0,0 +1,487 @@
+/*
+ * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/soc/mediatek/infracfg.h>
+#include <dt-bindings/power/mt8173-power.h>
+
+#define SPM_VDE_PWR_CON			0x0210
+#define SPM_MFG_PWR_CON			0x0214
+#define SPM_VEN_PWR_CON			0x0230
+#define SPM_ISP_PWR_CON			0x0238
+#define SPM_DIS_PWR_CON			0x023c
+#define SPM_VEN2_PWR_CON		0x0298
+#define SPM_AUDIO_PWR_CON		0x029c
+#define SPM_MFG_2D_PWR_CON		0x02c0
+#define SPM_MFG_ASYNC_PWR_CON		0x02c4
+#define SPM_USB_PWR_CON			0x02cc
+#define SPM_PWR_STATUS			0x060c
+#define SPM_PWR_STATUS_2ND		0x0610
+
+#define PWR_RST_B_BIT			BIT(0)
+#define PWR_ISO_BIT			BIT(1)
+#define PWR_ON_BIT			BIT(2)
+#define PWR_ON_2ND_BIT			BIT(3)
+#define PWR_CLK_DIS_BIT			BIT(4)
+
+#define PWR_STATUS_DISP			BIT(3)
+#define PWR_STATUS_MFG			BIT(4)
+#define PWR_STATUS_ISP			BIT(5)
+#define PWR_STATUS_VDEC			BIT(7)
+#define PWR_STATUS_VENC_LT		BIT(20)
+#define PWR_STATUS_VENC			BIT(21)
+#define PWR_STATUS_MFG_2D		BIT(22)
+#define PWR_STATUS_MFG_ASYNC		BIT(23)
+#define PWR_STATUS_AUDIO		BIT(24)
+#define PWR_STATUS_USB			BIT(25)
+
+enum clk_id {
+	MT8173_CLK_MM,
+	MT8173_CLK_MFG,
+	MT8173_CLK_NONE,
+	MT8173_CLK_MAX = MT8173_CLK_NONE,
+};
+
+struct scp_domain_data {
+	const char *name;
+	u32 sta_mask;
+	int ctl_offs;
+	u32 sram_pdn_bits;
+	u32 sram_pdn_ack_bits;
+	u32 bus_prot_mask;
+	enum clk_id clk_id;
+};
+
+static const struct scp_domain_data scp_domain_data[] __initconst = {
+	[MT8173_POWER_DOMAIN_VDEC] = {
+		.name = "vdec",
+		.sta_mask = PWR_STATUS_VDEC,
+		.ctl_offs = SPM_VDE_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(12, 12),
+		.clk_id = MT8173_CLK_MM,
+	},
+	[MT8173_POWER_DOMAIN_VENC] = {
+		.name = "venc",
+		.sta_mask = PWR_STATUS_VENC,
+		.ctl_offs = SPM_VEN_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(15, 12),
+		.clk_id = MT8173_CLK_MM,
+	},
+	[MT8173_POWER_DOMAIN_ISP] = {
+		.name = "isp",
+		.sta_mask = PWR_STATUS_ISP,
+		.ctl_offs = SPM_ISP_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(13, 12),
+		.clk_id = MT8173_CLK_MM,
+	},
+	[MT8173_POWER_DOMAIN_MM] = {
+		.name = "mm",
+		.sta_mask = PWR_STATUS_DISP,
+		.ctl_offs = SPM_DIS_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(12, 12),
+		.clk_id = MT8173_CLK_MM,
+		.bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MM_M0 |
+			MT8173_TOP_AXI_PROT_EN_MM_M1,
+	},
+	[MT8173_POWER_DOMAIN_VENC_LT] = {
+		.name = "venc_lt",
+		.sta_mask = PWR_STATUS_VENC_LT,
+		.ctl_offs = SPM_VEN2_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(15, 12),
+		.clk_id = MT8173_CLK_MM,
+	},
+	[MT8173_POWER_DOMAIN_AUDIO] = {
+		.name = "audio",
+		.sta_mask = PWR_STATUS_AUDIO,
+		.ctl_offs = SPM_AUDIO_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(15, 12),
+		.clk_id = MT8173_CLK_NONE,
+	},
+	[MT8173_POWER_DOMAIN_USB] = {
+		.name = "usb",
+		.sta_mask = PWR_STATUS_USB,
+		.ctl_offs = SPM_USB_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(15, 12),
+		.clk_id = MT8173_CLK_NONE,
+	},
+	[MT8173_POWER_DOMAIN_MFG_ASYNC] = {
+		.name = "mfg_async",
+		.sta_mask = PWR_STATUS_MFG_ASYNC,
+		.ctl_offs = SPM_MFG_ASYNC_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = 0,
+		.clk_id = MT8173_CLK_MFG,
+	},
+	[MT8173_POWER_DOMAIN_MFG_2D] = {
+		.name = "mfg_2d",
+		.sta_mask = PWR_STATUS_MFG_2D,
+		.ctl_offs = SPM_MFG_2D_PWR_CON,
+		.sram_pdn_bits = GENMASK(11, 8),
+		.sram_pdn_ack_bits = GENMASK(13, 12),
+		.clk_id = MT8173_CLK_NONE,
+	},
+	[MT8173_POWER_DOMAIN_MFG] = {
+		.name = "mfg",
+		.sta_mask = PWR_STATUS_MFG,
+		.ctl_offs = SPM_MFG_PWR_CON,
+		.sram_pdn_bits = GENMASK(13, 8),
+		.sram_pdn_ack_bits = GENMASK(21, 16),
+		.clk_id = MT8173_CLK_NONE,
+		.bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MFG_S |
+			MT8173_TOP_AXI_PROT_EN_MFG_M0 |
+			MT8173_TOP_AXI_PROT_EN_MFG_M1 |
+			MT8173_TOP_AXI_PROT_EN_MFG_SNOOP_OUT,
+	},
+};
+
+#define NUM_DOMAINS	ARRAY_SIZE(scp_domain_data)
+
+struct scp;
+
+struct scp_domain {
+	struct generic_pm_domain genpd;
+	struct scp *scp;
+	struct clk *clk;
+	u32 sta_mask;
+	void __iomem *ctl_addr;
+	u32 sram_pdn_bits;
+	u32 sram_pdn_ack_bits;
+	u32 bus_prot_mask;
+};
+
+struct scp {
+	struct scp_domain domains[NUM_DOMAINS];
+	struct genpd_onecell_data pd_data;
+	struct device *dev;
+	void __iomem *base;
+	struct regmap *infracfg;
+};
+
+static int scpsys_domain_is_on(struct scp_domain *scpd)
+{
+	struct scp *scp = scpd->scp;
+
+	u32 status = readl(scp->base + SPM_PWR_STATUS) & scpd->sta_mask;
+	u32 status2 = readl(scp->base + SPM_PWR_STATUS_2ND) & scpd->sta_mask;
+
+	/*
+	 * A domain is on when both status bits are set. If only one is set
+	 * return an error. This happens while powering up a domain
+	 */
+
+	if (status && status2)
+		return true;
+	if (!status && !status2)
+		return false;
+
+	return -EINVAL;
+}
+
+static int scpsys_power_on(struct generic_pm_domain *genpd)
+{
+	struct scp_domain *scpd = container_of(genpd, struct scp_domain, genpd);
+	struct scp *scp = scpd->scp;
+	unsigned long timeout;
+	bool expired;
+	void __iomem *ctl_addr = scpd->ctl_addr;
+	u32 sram_pdn_ack = scpd->sram_pdn_ack_bits;
+	u32 val;
+	int ret;
+
+	if (scpd->clk) {
+		ret = clk_prepare_enable(scpd->clk);
+		if (ret)
+			goto err_clk;
+	}
+
+	val = readl(ctl_addr);
+	val |= PWR_ON_BIT;
+	writel(val, ctl_addr);
+	val |= PWR_ON_2ND_BIT;
+	writel(val, ctl_addr);
+
+	/* wait until PWR_ACK = 1 */
+	timeout = jiffies + HZ;
+	expired = false;
+	while (1) {
+		ret = scpsys_domain_is_on(scpd);
+		if (ret > 0)
+			break;
+
+		if (expired) {
+			ret = -ETIMEDOUT;
+			goto err_pwr_ack;
+		}
+
+		cpu_relax();
+
+		if (time_after(jiffies, timeout))
+			expired = true;
+	}
+
+	val &= ~PWR_CLK_DIS_BIT;
+	writel(val, ctl_addr);
+
+	val &= ~PWR_ISO_BIT;
+	writel(val, ctl_addr);
+
+	val |= PWR_RST_B_BIT;
+	writel(val, ctl_addr);
+
+	val &= ~scpd->sram_pdn_bits;
+	writel(val, ctl_addr);
+
+	/* wait until SRAM_PDN_ACK all 0 */
+	timeout = jiffies + HZ;
+	expired = false;
+	while (sram_pdn_ack && (readl(ctl_addr) & sram_pdn_ack)) {
+
+		if (expired) {
+			ret = -ETIMEDOUT;
+			goto err_pwr_ack;
+		}
+
+		cpu_relax();
+
+		if (time_after(jiffies, timeout))
+			expired = true;
+	}
+
+	if (scpd->bus_prot_mask) {
+		ret = mtk_infracfg_clear_bus_protection(scp->infracfg,
+				scpd->bus_prot_mask);
+		if (ret)
+			goto err_pwr_ack;
+	}
+
+	return 0;
+
+err_pwr_ack:
+	clk_disable_unprepare(scpd->clk);
+err_clk:
+	dev_err(scp->dev, "Failed to power on domain %s\n", genpd->name);
+
+	return ret;
+}
+
+static int scpsys_power_off(struct generic_pm_domain *genpd)
+{
+	struct scp_domain *scpd = container_of(genpd, struct scp_domain, genpd);
+	struct scp *scp = scpd->scp;
+	unsigned long timeout;
+	bool expired;
+	void __iomem *ctl_addr = scpd->ctl_addr;
+	u32 pdn_ack = scpd->sram_pdn_ack_bits;
+	u32 val;
+	int ret;
+
+	if (scpd->bus_prot_mask) {
+		ret = mtk_infracfg_set_bus_protection(scp->infracfg,
+				scpd->bus_prot_mask);
+		if (ret)
+			goto out;
+	}
+
+	val = readl(ctl_addr);
+	val |= scpd->sram_pdn_bits;
+	writel(val, ctl_addr);
+
+	/* wait until SRAM_PDN_ACK all 1 */
+	timeout = jiffies + HZ;
+	expired = false;
+	while (pdn_ack && (readl(ctl_addr) & pdn_ack) != pdn_ack) {
+		if (expired) {
+			ret = -ETIMEDOUT;
+			goto out;
+		}
+
+		cpu_relax();
+
+		if (time_after(jiffies, timeout))
+			expired = true;
+	}
+
+	val |= PWR_ISO_BIT;
+	writel(val, ctl_addr);
+
+	val &= ~PWR_RST_B_BIT;
+	writel(val, ctl_addr);
+
+	val |= PWR_CLK_DIS_BIT;
+	writel(val, ctl_addr);
+
+	val &= ~PWR_ON_BIT;
+	writel(val, ctl_addr);
+
+	val &= ~PWR_ON_2ND_BIT;
+	writel(val, ctl_addr);
+
+	/* wait until PWR_ACK = 0 */
+	timeout = jiffies + HZ;
+	expired = false;
+	while (1) {
+		ret = scpsys_domain_is_on(scpd);
+		if (ret == 0)
+			break;
+
+		if (expired) {
+			ret = -ETIMEDOUT;
+			goto out;
+		}
+
+		cpu_relax();
+
+		if (time_after(jiffies, timeout))
+			expired = true;
+	}
+
+	if (scpd->clk)
+		clk_disable_unprepare(scpd->clk);
+
+	return 0;
+
+out:
+	dev_err(scp->dev, "Failed to power off domain %s\n", genpd->name);
+
+	return ret;
+}
+
+static int __init scpsys_probe(struct platform_device *pdev)
+{
+	struct genpd_onecell_data *pd_data;
+	struct resource *res;
+	int i, ret;
+	struct scp *scp;
+	struct clk *clk[MT8173_CLK_MAX];
+
+	scp = devm_kzalloc(&pdev->dev, sizeof(*scp), GFP_KERNEL);
+	if (!scp)
+		return -ENOMEM;
+
+	scp->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	scp->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(scp->base))
+		return PTR_ERR(scp->base);
+
+	pd_data = &scp->pd_data;
+
+	pd_data->domains = devm_kzalloc(&pdev->dev,
+			sizeof(*pd_data->domains) * NUM_DOMAINS, GFP_KERNEL);
+	if (!pd_data->domains)
+		return -ENOMEM;
+
+	clk[MT8173_CLK_MM] = devm_clk_get(&pdev->dev, "mm");
+	if (IS_ERR(clk[MT8173_CLK_MM]))
+		return PTR_ERR(clk[MT8173_CLK_MM]);
+
+	clk[MT8173_CLK_MFG] = devm_clk_get(&pdev->dev, "mfg");
+	if (IS_ERR(clk[MT8173_CLK_MFG]))
+		return PTR_ERR(clk[MT8173_CLK_MFG]);
+
+	scp->infracfg = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+			"infracfg");
+	if (IS_ERR(scp->infracfg)) {
+		dev_err(&pdev->dev, "Cannot find infracfg controller: %ld\n",
+				PTR_ERR(scp->infracfg));
+		return PTR_ERR(scp->infracfg);
+	}
+
+	pd_data->num_domains = NUM_DOMAINS;
+
+	for (i = 0; i < NUM_DOMAINS; i++) {
+		struct scp_domain *scpd = &scp->domains[i];
+		struct generic_pm_domain *genpd = &scpd->genpd;
+		const struct scp_domain_data *data = &scp_domain_data[i];
+
+		pd_data->domains[i] = genpd;
+		scpd->scp = scp;
+
+		scpd->sta_mask = data->sta_mask;
+		scpd->ctl_addr = scp->base + data->ctl_offs;
+		scpd->sram_pdn_bits = data->sram_pdn_bits;
+		scpd->sram_pdn_ack_bits = data->sram_pdn_ack_bits;
+		scpd->bus_prot_mask = data->bus_prot_mask;
+		if (data->clk_id != MT8173_CLK_NONE)
+			scpd->clk = clk[data->clk_id];
+
+		genpd->name = data->name;
+		genpd->power_off = scpsys_power_off;
+		genpd->power_on = scpsys_power_on;
+
+		/*
+		 * Initially turn on all domains to make the domains usable
+		 * with !CONFIG_PM and to get the hardware in sync with the
+		 * software.  The unused domains will be switched off during
+		 * late_init time.
+		 */
+		genpd->power_on(genpd);
+
+		pm_genpd_init(genpd, NULL, false);
+	}
+
+	/*
+	 * We are not allowed to fail here since there is no way to unregister
+	 * a power domain. Once registered above we have to keep the domains
+	 * valid.
+	 */
+
+	ret = pm_genpd_add_subdomain(pd_data->domains[MT8173_POWER_DOMAIN_MFG_ASYNC],
+		pd_data->domains[MT8173_POWER_DOMAIN_MFG_2D]);
+	if (ret && IS_ENABLED(CONFIG_PM))
+		dev_err(&pdev->dev, "Failed to add subdomain: %d\n", ret);
+
+	ret = pm_genpd_add_subdomain(pd_data->domains[MT8173_POWER_DOMAIN_MFG_2D],
+		pd_data->domains[MT8173_POWER_DOMAIN_MFG]);
+	if (ret && IS_ENABLED(CONFIG_PM))
+		dev_err(&pdev->dev, "Failed to add subdomain: %d\n", ret);
+
+	ret = of_genpd_add_provider_onecell(pdev->dev.of_node, pd_data);
+	if (ret)
+		dev_err(&pdev->dev, "Failed to add OF provider: %d\n", ret);
+
+	return 0;
+}
+
+static const struct of_device_id of_scpsys_match_tbl[] = {
+	{
+		.compatible = "mediatek,mt8173-scpsys",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct platform_driver scpsys_drv = {
+	.driver = {
+		.name = "mtk-scpsys",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(of_scpsys_match_tbl),
+	},
+};
+
+module_platform_driver_probe(scpsys_drv, scpsys_probe);