Re: [PATCH 3/5] soc: Mediatek: Add SCPSYS power domain driver

From: Sascha Hauer
Date: Tue May 19 2015 - 06:30:24 EST

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On Fri, May 15, 2015 at 10:17:21PM +0800, Daniel Kurtz wrote:
> On Tue, May 12, 2015 at 3:23 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
> > 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@xxxxxxxxxxxxxx>
> > ---
> > .../devicetree/bindings/soc/mediatek/scpsys.txt | 2 +
> > drivers/soc/mediatek/Kconfig | 8 +
> > drivers/soc/mediatek/Makefile | 1 +
> > drivers/soc/mediatek/mtk-scpsys.c | 416 +++++++++++++++++++++
> > include/dt-bindings/power/mt8173-power.h | 15 +
> > 5 files changed, 442 insertions(+)
> > create mode 100644 drivers/soc/mediatek/mtk-scpsys.c
> > create mode 100644 include/dt-bindings/power/mt8173-power.h
> >
> > diff --git a/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt b/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt
> > index 4764a03..87f2091 100644
> > --- a/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt
> > +++ b/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt
> > @@ -15,6 +15,7 @@ Required properties:
> > - compatible: Must be "mediatek,mt8173-scpsys"
> > - #power-domain-cells: Must be 1
> > - reg: Address range of the SCPSYS unit
> > +- infracfg: must contain a phandle to the infracfg controller
> >
> > Example:
> >
> > @@ -22,6 +23,7 @@ Example:
> > #power-domain-cells = <1>;
> > compatible = "mediatek,mt8173-scpsys";
> > reg = <0 0x10006000 0 0x1000>;
> > + infracfg = <&infracfg>;
> > };
> >
> > Example consumer:
> > diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> > index 6fae66f..1386c79 100644
> > --- a/drivers/soc/mediatek/Kconfig
> > +++ b/drivers/soc/mediatek/Kconfig
> > @@ -18,3 +18,11 @@ config MTK_INFRACFG
> > Say yes here to add support for the MediaTek INFRACFG controller. The
> > INFRACFG controller contains various infrastructure registers not
> > directly associated to any device.
> > +
> > +config MTK_SCPSYS
> > + tristate "MediaTek SCPSYS Support"
> > + depends on MTK_INFRACFG
>
> Should this be:
> depends on ARCH_MEDIATEK || COMPILE_TEST
> selects MTK_INFRACFG
>
> > + select REGMAP
> > + 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 ce39119..f8eebab 100644
> > --- a/drivers/soc/mediatek/Makefile
> > +++ b/drivers/soc/mediatek/Makefile
> > @@ -1,2 +1,3 @@
> > obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
> > obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.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 0000000..c42c7f1
> > --- /dev/null
> > +++ b/drivers/soc/mediatek/mtk-scpsys.c
> > @@ -0,0 +1,416 @@
> > +/*
> > + * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@xxxxxxxxxxxxxx>
> > + *
> > + * 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/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/pm_domain.h>
> > +#include <linux/delay.h>
> > +#include <linux/soc/mediatek/infracfg.h>
> > +#include <dt-bindings/power/mt8173-power.h>
> > +#include <linux/mfd/syscon.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 DIS_PWR_STA_MASK BIT(3)
> > +#define MFG_PWR_STA_MASK BIT(4)
> > +#define ISP_PWR_STA_MASK BIT(5)
> > +#define VDE_PWR_STA_MASK BIT(7)
> > +#define VEN2_PWR_STA_MASK BIT(20)
> > +#define VEN_PWR_STA_MASK BIT(21)
> > +#define MFG_2D_PWR_STA_MASK BIT(22)
> > +#define MFG_ASYNC_PWR_STA_MASK BIT(23)
> > +#define AUDIO_PWR_STA_MASK BIT(24)
> > +#define USB_PWR_STA_MASK BIT(25)
> > +
> > +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;
> > + int id;
> > + const char *clk_name;
> > +};
>
> These fields are only used at init time:
> name (the pointer, the actual string is pointed to by genpd->name)
> id
> clk_name
>
> You could split those off into a separate __initconst struct.

Is this really worth it?

>
> > +
> > +static const struct scp_domain_data scp_domain_data[] = {
> > + {
> > + .id = MT8173_POWER_DOMAIN_VDE,
> > + .name = "vde",
> > + .sta_mask = VDE_PWR_STA_MASK,
> > + .ctl_offs = SPM_VDE_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(12, 12),
> > + .clk_name = "vdec",
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_VEN,
>
> Is there any reason you do not keep these in ".id" order:
> VDE, MFG, VEN, ISP, DIS, VEN2, AUDIO, MFG_2D, MFG_ASYNC, USB

The reason is simply that with CONFIG_PM disabled we have to turn on the
domains in the correct order, otherwise the system hangs. I can renumber
the defines though if you like.

> > + }, {
> > + .id = MT8173_POWER_DOMAIN_ISP,
> > + .name = "isp",
> > + .sta_mask = ISP_PWR_STA_MASK,
> > + .ctl_offs = SPM_ISP_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(13, 12),
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_DIS,
> > + .name = "disp",
>
> Perhaps .id/.name/.clk should be "MM" to match the corresponding clock
> define (CLK_TOP_MM_SEL) & prot bits.

>
> > + .sta_mask = DIS_PWR_STA_MASK,
> > + .ctl_offs = SPM_DIS_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(12, 12),
> > + .clk_name = "disp",
> > + .bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MM_M0 |
> > + MT8173_TOP_AXI_PROT_EN_MM_M1,
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_VEN2,
> > + .name = "ven2",
>
> Perhaps .id/.name/.clk should be "VENC_LT"/"venc_lt" to match the
> corresponding clock define (CLK_TOP_VENC_LT_SEL).
>
> > + .sta_mask = VEN2_PWR_STA_MASK,
> > + .ctl_offs = SPM_VEN2_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(15, 12),
> > + .clk_name = "ven2",
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_AUDIO,
> > + .name = "audio",
> > + .sta_mask = AUDIO_PWR_STA_MASK,
> > + .ctl_offs = SPM_AUDIO_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(15, 12),
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_MFG_ASYNC,
> > + .name = "mfg_async",
> > + .sta_mask = MFG_ASYNC_PWR_STA_MASK,
> > + .ctl_offs = SPM_MFG_ASYNC_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = 0,
> > + .clk_name = "mfg",
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_MFG_2D,
> > + .name = "mfg_2d",
> > + .sta_mask = MFG_2D_PWR_STA_MASK,
> > + .ctl_offs = SPM_MFG_2D_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(13, 12),
> > + .clk_name = "mfg",
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_MFG,
> > + .name = "mfg",
> > + .sta_mask = MFG_PWR_STA_MASK,
> > + .ctl_offs = SPM_MFG_PWR_CON,
> > + .sram_pdn_bits = GENMASK(13, 8),
> > + .sram_pdn_ack_bits = GENMASK(21, 16),
> > + .clk_name = "mfg",
> > + .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,
> > + }, {
> > + .id = MT8173_POWER_DOMAIN_USB,
> > + .name = "usb",
> > + .sta_mask = USB_PWR_STA_MASK,
> > + .ctl_offs = SPM_USB_PWR_CON,
> > + .sram_pdn_bits = GENMASK(11, 8),
> > + .sram_pdn_ack_bits = GENMASK(15, 12),
> > + },
> > +};
> > +
> > +#define NUM_DOMAINS ARRAY_SIZE(scp_domain_data)
> > +
> > +struct scp;
> > +
> > +struct scp_domain {
> > + struct generic_pm_domain pmd;
>
> Could you name this "genpd"... that seems to be what most other drivers use.

ok

>
> > + const struct scp_domain_data *data;
> > + struct scp *scp;
> > + struct clk *clk;
> > +};
> > +
> > +struct scp {
> > + struct scp_domain domains[NUM_DOMAINS];
> > + struct genpd_onecell_data pd_data;
>
> After probe() you don't use pd_data.
> Why do we need it in this struct?

Just to save another extra allocation for it.

>
> > + struct device *dev;
> > + void __iomem *base;
> > + struct regmap *infracfg;
> > +};
> > +
> > +static int scpsys_power_on(struct generic_pm_domain *genpd)
> > +{
> > + struct scp_domain *scpd = container_of(genpd, struct scp_domain, pmd);
> > + struct scp *scp = scpd->scp;
> > + const struct scp_domain_data *data = scpd->data;
> > + unsigned long expired;
> > + void __iomem *ctl_addr = scpd->scp->base + data->ctl_offs;
> > + u32 sram_pdn_ack = data->sram_pdn_ack_bits;
> > + u32 val;
> > + int ret;
> > +
> > + if (scpd->clk) {
> > + ret = clk_prepare_enable(scpd->clk);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + 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 */
> > + expired = jiffies + HZ;
> > + while (!(readl(scp->base + SPM_PWR_STATUS) & data->sta_mask) ||
> > + !(readl(scp->base + SPM_PWR_STATUS_2ND) & data->sta_mask)) {
> > + cpu_relax();
> > + if (time_after(jiffies, expired)) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > + }
> > +
> > + 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 &= ~data->sram_pdn_bits;
> > + writel(val, ctl_addr);
> > +
> > + /* wait until SRAM_PDN_ACK all 0 */
> > + expired = jiffies + HZ;
> > + while (sram_pdn_ack && (readl(ctl_addr) & sram_pdn_ack)) {
> > + cpu_relax();
> > + if (time_after(jiffies, expired)) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > + }
> > +
> > + if (data->bus_prot_mask) {
> > + ret = mtk_infracfg_clear_bus_protection(scp->infracfg,
> > + data->bus_prot_mask);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + return 0;
> > +out:
> > + dev_err(scp->dev, "Failed to power on domain %s\n", scpd->data->name);
>
> genpd->name should be sufficient

ok

>
> > +
> > + return ret;
> > +}
> > +
> > +static int scpsys_power_off(struct generic_pm_domain *genpd)
> > +{
> > + struct scp_domain *scpd = container_of(genpd, struct scp_domain, pmd);
> > + struct scp *scp = scpd->scp;
> > + const struct scp_domain_data *data = scpd->data;
> > + unsigned long expired;
> > + void __iomem *ctl_addr = scpd->scp->base + data->ctl_offs;
> > + u32 sram_pdn_ack = data->sram_pdn_ack_bits;
> > + u32 val;
> > + int ret;
> > +
> > + if (data->bus_prot_mask) {
> > + ret = mtk_infracfg_set_bus_protection(scp->infracfg,
> > + data->bus_prot_mask);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + val = readl(ctl_addr);
> > + val |= data->sram_pdn_bits;
> > + writel(val, ctl_addr);
> > +
> > + /* wait until SRAM_PDN_ACK all 1 */
> > + expired = jiffies + HZ;
> > + while ((readl(ctl_addr) & sram_pdn_ack) != sram_pdn_ack) {
> > + cpu_relax();
> > + if (time_after(jiffies, expired)) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > + }
> > +
> > + 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 */
> > + expired = jiffies + HZ;
> > + while ((readl(scp->base + SPM_PWR_STATUS) & data->sta_mask) ||
> > + (readl(scp->base + SPM_PWR_STATUS_2ND) & data->sta_mask)) {
> > + cpu_relax();
> > + if (time_after(jiffies, expired)) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > + }
> > +
> > + if (scpd->clk)
> > + clk_disable_unprepare(scpd->clk);
> > +
> > + return 0;
> > +
> > +out:
> > + dev_err(scp->dev, "Failed to power off domain %s\n", scpd->data->name);
> > +
> > + return ret;
> > +}
> > +
> > +static int scpsys_probe(struct platform_device *pdev)
> > +{
> > + struct genpd_onecell_data *pd_data;
> > + struct resource *res;
> > + int i;
> > + struct scp *scp;
> > +
> > + 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;
> > +
> > + 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];
> > +
> > + if (scp_domain_data[i].clk_name) {
> > + const char *name = scp_domain_data[i].clk_name;
> > +
> > + scpd->clk = devm_clk_get(&pdev->dev, name);
> > + if (IS_ERR(scpd->clk)) {
> > + dev_err(&pdev->dev, "Failed to get %s clk: %ld\n",
> > + name, PTR_ERR(scpd->clk));
> > + return PTR_ERR(scpd->clk);
> > + }
> > + }
> > + }
> > +
> > + for (i = 0; i < NUM_DOMAINS; i++) {
> > + struct scp_domain *scpd = &scp->domains[i];
> > + struct generic_pm_domain *pmd = &scpd->pmd;
> > +
> > + pd_data->domains[scp_domain_data[i].id] = pmd;
> > + scpd->data = &scp_domain_data[i];
> > + scpd->scp = scp;
> > +
> > + pmd->name = scp_domain_data[i].name;
> > + pmd->power_off = scpsys_power_off;
> > + pmd->power_on = scpsys_power_on;
> > + pmd->power_off_latency_ns = 20000;
> > + pmd->power_on_latency_ns = 20000;
>
> Where did these latency values come from?

>From reducing them to 0 and seeing where the end results end up being.
The power domain code increases the times automatically when the values
are exceeded.

>
> > +
> > + pm_genpd_init(pmd, NULL, true);
>
> I'm not sure how this works... does this mean that all power domains
> initially off?

Some are off, others are on. I'll change that to:

- call scpsys_power_on for all domains so I know they are turned on
- call pm_genpd_init(pmd, NULL, false);
- Let the pm core disable the unused domains in the late_initcall

That's the only way I found to properly sync the hardware state with the
software state also with regard to the clocks.

>
> > +
> > + /*
> > + * If PM is disabled turn on all domains by default so that
> > + * consumers can work.
> > + */
> > + if (!IS_ENABLED(CONFIG_PM))
> > + pmd->power_on(pmd);
> > + }
> > +
> > + pm_genpd_add_subdomain(&scp->domains[MT8173_POWER_DOMAIN_MFG_ASYNC].pmd,
> > + &scp->domains[MT8173_POWER_DOMAIN_MFG_2D].pmd);
> > + pm_genpd_add_subdomain(&scp->domains[MT8173_POWER_DOMAIN_MFG_2D].pmd,
> > + &scp->domains[MT8173_POWER_DOMAIN_MFG].pmd);
> > +
>
> (1) nit: the continuation lines needs 1 more indent.
>
> (2) Why aren't you checking for errors?

I'll check for errors next round. However, I cannot bail out in this
case since once pm_genpd_init() is called the domain cannot be
unregistered anymore.

Sascha

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