Re: [PATCH v6 03/11] soc: renesas: rcar-sysc: Add DT support for SYSC PM domains

Laurent Pinchart
2016-04-20T13:59:54Z

Hi Geert,

Thank you for the patch.

On Wednesday 20 Apr 2016 14:02:38 Geert Uytterhoeven wrote:
> Populate the SYSC PM domains from DT, based on the presence of a device
> node for the System Controller. The actual power area hiearchy, and
> features of specific areas are obtained from tables in the C code.
>
> The SYSCIER and SYSCIMR register values are derived from the power areas
> present, which will help to get rid of the hardcoded values in R-Car H1
> and R-Car Gen2 platform code later.
>
> Initialization is done from an early_initcall(), to make sure the PM
> Domains are initialized before secondary CPU bringup.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> v6:
> - Drop unneeded genpd->dev_ops.active_wakeup callback,
> - Move call to pm_genpd_init() after all local initialization,
>
> v5:
> - Mask SYSC interrupts sources before enabling them (doesn't matter
> much as they're disabled at the GIC level anyway),
> - Re-add explicit "always-on" power area instead of aliasing the SoC's
> Clock Domain,
> - Merge the two initialization phases again,
>
> v4:
> - Make sure not to clear reserved SYSCIMR bits that were set before,
> - Make the always-on power area implicit and always present, and an
> alias of the existing SoC's Clock Domain. This makes the number of
> power areas a compile-time constant, and allows to drop PD_ALWAYS_ON
> and some checks.
> - Split initialization in two phases,
> - Document that ARM cores are controlled by PSCI on R-Car Gen3
> (although the underlying CPG/APMU hardware is the same as on Gen2),
> - Minor improvements (double evaluation, unused parameter, debug
> message consolidation),
>
> v3:
> - Drop check for CONFIG_PM_GENERIC_DOMAINS, which is now always
> enabled on R-Car SoCs,
> - Create PM Domains from hierarchy in C data instead of DT,
> - Initialize SYSCIER early, as SYSC needs the interrupt sources to be
> enabled to control power,
> - Mask all SYSC interrupt sources for the CPU,
> - Add support for an "always-on" domain,
> - Use early_initcall() instead of core_initcall(),
> - Do not power up CPU power areas during initialization, as this is
> handled later (directly or indirectly) by the SMP code,
>
> v2:
> - Add missing definitions for SYSC_PWR_CA15_CPU and SYSC_PWR_CA7_CPU,
> - Add R-Car H3 (r8a7795) support,
> - Drop tests for CONFIG_ARCH_SHMOBILE_LEGACY,
> - Add missing break statements in rcar_sysc_pwr_on_off(),
> - Add missing calls to of_node_put() in error paths,
> - Fix build if CONFIG_PM=n,
> - Update compatible values,
> - Update copyright.
> ---
> drivers/soc/renesas/rcar-sysc.c | 202
> +++++++++++++++++++++++++++++++++++++++- drivers/soc/renesas/rcar-sysc.h |
> 53 +++++++++++
> 2 files changed, 254 insertions(+), 1 deletion(-)
> create mode 100644 drivers/soc/renesas/rcar-sysc.h
>
> diff --git a/drivers/soc/renesas/rcar-sysc.c
> b/drivers/soc/renesas/rcar-sysc.c index 9ba5fd15c53bf9b9..95f2b59cbd76f777
> 100644
> --- a/drivers/soc/renesas/rcar-sysc.c
> +++ b/drivers/soc/renesas/rcar-sysc.c
> @@ -2,6 +2,7 @@
> * R-Car SYSC Power management support
> *
> * Copyright (C) 2014 Magnus Damm
> + * Copyright (C) 2015-2016 Glider bvba
> *
> * This file is subject to the terms and conditions of the GNU General
> Public * License. See the file "COPYING" in the main directory of this
> archive @@ -11,10 +12,15 @@
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/mm.h>
> +#include <linux/of_address.h>
> +#include <linux/pm_domain.h>
> +#include <linux/slab.h>
> #include <linux/spinlock.h>
> #include <linux/io.h>
> #include <linux/soc/renesas/rcar-sysc.h>
>
> +#include "rcar-sysc.h"
> +
> /* SYSC Common */
> #define SYSCSR 0x00 /* SYSC Status Register */
> #define SYSCISR 0x04 /* Interrupt Status Register */
> @@ -29,7 +35,8 @@
> /*
> * Power Control Register Offsets inside the register block for each domain
> * Note: The "CR" registers for ARM cores exist on H1 only
> - * Use WFI to power off, CPG/APMU to resume ARM cores on R-Car Gen2
> + * Use WFI to power off, CPG/APMU to resume ARM cores on R-Car Gen2
> + * Use PSCI on R-Car Gen3
> */
> #define PWRSR_OFFS 0x00 /* Power Status Register */
> #define PWROFFCR_OFFS 0x04 /* Power Shutoff Control Register */
> @@ -48,6 +55,8 @@
> #define SYSCISR_RETRIES 1000
> #define SYSCISR_DELAY_US 1
>
> +#define RCAR_PD_ALWAYS_ON 32 /* Always-on power area */
> +
> static void __iomem *rcar_sysc_base;
> static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */
>
> @@ -162,3 +171,194 @@ void __iomem *rcar_sysc_init(phys_addr_t base)
>
> return rcar_sysc_base;
> }
> +
> +struct rcar_sysc_pd {
> + struct generic_pm_domain genpd;
> + struct rcar_sysc_ch ch;
> + unsigned int flags;
> + char name[0];
> +};
> +
> +static inline struct rcar_sysc_pd *to_rcar_pd(struct generic_pm_domain *d)
> +{
> + return container_of(d, struct rcar_sysc_pd, genpd);
> +}
> +
> +static int rcar_sysc_pd_power_off(struct generic_pm_domain *genpd)
> +{
> + struct rcar_sysc_pd *pd = to_rcar_pd(genpd);
> +
> + pr_debug("%s: %s\n", __func__, genpd->name);
> +
> + if (pd->flags & PD_NO_CR) {
> + pr_debug("%s: Cannot control %s\n", __func__, genpd->name);
> + return -EBUSY;
> + }
> +
> + if (pd->flags & PD_BUSY) {
> + pr_debug("%s: %s busy\n", __func__, genpd->name);
> + return -EBUSY;
> + }
> +
> + return rcar_sysc_power_down(&pd->ch);
> +}
> +
> +static int rcar_sysc_pd_power_on(struct generic_pm_domain *genpd)
> +{
> + struct rcar_sysc_pd *pd = to_rcar_pd(genpd);
> +
> + pr_debug("%s: %s\n", __func__, genpd->name);
> +
> + if (pd->flags & PD_NO_CR) {
> + pr_debug("%s: Cannot control %s\n", __func__, genpd->name);
> + return 0;
> + }
> +
> + return rcar_sysc_power_up(&pd->ch);
> +}
> +
> +static void __init rcar_sysc_pd_setup(struct rcar_sysc_pd *pd)
> +{
> + struct generic_pm_domain *genpd = &pd->genpd;
> + const char *name = pd->genpd.name;
> + struct dev_power_governor *gov = &simple_qos_governor;
> +
> + if (pd->flags & PD_CPU) {
> + /*
> + * This domain contains a CPU core and therefore it should
> + * only be turned off if the CPU is not in use.
> + */
> + pr_debug("PM domain %s contains %s\n", name, "CPU");
> + pd->flags |= PD_BUSY;
> + gov = &pm_domain_always_on_gov;
> + } else if (pd->flags & PD_SCU) {
> + /*
> + * This domain contains an SCU and cache-controller, and
> + * therefore it should only be turned off if the CPU cores are
> + * not in use.
> + */
> + pr_debug("PM domain %s contains %s\n", name, "SCU");
> + pd->flags |= PD_BUSY;
> + gov = &pm_domain_always_on_gov;
> + } else if (pd->flags & PD_NO_CR) {
> + /*
> + * This domain cannot be turned off.
> + */
> + pd->flags |= PD_BUSY;
> + gov = &pm_domain_always_on_gov;
> + }
> +
> + genpd->power_off = rcar_sysc_pd_power_off;
> + genpd->power_on = rcar_sysc_pd_power_on;
> +
> + if (pd->flags & (PD_CPU | PD_NO_CR)) {
> + /* Skip CPUs (handled by SMP code) and areas without control */
> + pr_debug("%s: Not touching %s\n", __func__, genpd->name);
> + goto finalize;
> + }
> +
> + if (!rcar_sysc_power_is_off(&pd->ch)) {
> + pr_debug("%s: %s is already powered\n", __func__, genpd->name);
> + goto finalize;
> + }
> +
> + rcar_sysc_power_up(&pd->ch);
> +
> +finalize:
> + pm_genpd_init(genpd, gov, false);
> +}
> +
> +static const struct of_device_id rcar_sysc_matches[] = {
> + { /* sentinel */ }
> +};
> +
> +struct rcar_pm_domains {
> + struct genpd_onecell_data onecell_data;
> + struct generic_pm_domain *domains[RCAR_PD_ALWAYS_ON + 1];
> +};
> +
> +static int __init rcar_sysc_pd_init(void)
> +{
> + const struct rcar_sysc_info *info;
> + const struct of_device_id *match;
> + struct rcar_pm_domains *domains;
> + struct device_node *np;
> + u32 syscier, syscimr;
> + void __iomem *base;
> + unsigned int i;
> + int error;
> +
> + np = of_find_matching_node_and_match(NULL, rcar_sysc_matches, &match);
> + if (!np)
> + return -ENODEV;
> +
> + info = match->data;
> +
> + base = of_iomap(np, 0);
> + if (!base) {
> + pr_warn("%s: Cannot map regs\n", np->full_name);
> + error = -ENOMEM;
> + goto out_put;
> + }
> +
> + rcar_sysc_base = base;
> +
> + domains = kzalloc(sizeof(*domains), GFP_KERNEL);
> + if (!domains) {
> + error = -ENOMEM;
> + goto out_put;
> + }
> +
> + domains->onecell_data.domains = domains->domains;
> + domains->onecell_data.num_domains = ARRAY_SIZE(domains->domains);
> +
> + for (i = 0, syscier = 0; i < info->num_areas; i++)
> + syscier |= BIT(info->areas[i].isr_bit);
> +
> + /*
> + * Mask all interrupt sources to prevent the CPU from receiving them.
> + * Make sure not to clear reserved bits that were set before.
> + */
> + syscimr = ioread32(base + SYSCIMR);
> + syscimr |= syscier;
> + pr_debug("%s: syscimr = 0x%08x\n", np->full_name, syscimr);
> + iowrite32(syscimr, base + SYSCIMR);
> +
> + /*
> + * SYSC needs all interrupt sources enabled to control power.
> + */
> + pr_debug("%s: syscier = 0x%08x\n", np->full_name, syscier);
> + iowrite32(syscier, base + SYSCIER);
> +
> + for (i = 0; i < info->num_areas; i++) {
> + const struct rcar_sysc_area *area = &info->areas[i];
> + struct rcar_sysc_pd *pd;
> +
> + pd = kzalloc(sizeof(*pd) + strlen(area->name) + 1, GFP_KERNEL);
> + if (!pd) {
> + error = -ENOMEM;
> + goto out_put;
> + }
> +
> + strcpy(pd->name, area->name);
> + pd->genpd.name = pd->name;
> + pd->ch.chan_offs = area->chan_offs;
> + pd->ch.chan_bit = area->chan_bit;
> + pd->ch.isr_bit = area->isr_bit;
> + pd->flags = area->flags;
> +
> + rcar_sysc_pd_setup(pd);
> + if (area->parent >= 0)
> + pm_genpd_add_subdomain(domains->domains[area->parent],
> + &pd->genpd);
> +
> + domains->domains[area->isr_bit] = &pd->genpd;
> + }
> +
> + of_genpd_add_provider_onecell(np, &domains->onecell_data);
> +
> +out_put:
> + of_node_put(np);
> + return error;
> +}
> +early_initcall(rcar_sysc_pd_init);
> diff --git a/drivers/soc/renesas/rcar-sysc.h
> b/drivers/soc/renesas/rcar-sysc.h new file mode 100644
> index 0000000000000000..7bb48b4f7334f960
> --- /dev/null
> +++ b/drivers/soc/renesas/rcar-sysc.h
> @@ -0,0 +1,53 @@
> +/*
> + * Renesas R-Car System Controller
> + *
> + * Copyright (C) 2016 Glider bvba
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + */
> +#ifndef __SOC_RENESAS_RCAR_SYSC_H__
> +#define __SOC_RENESAS_RCAR_SYSC_H__
> +
> +#include <linux/types.h>
> +
> +
> +/*
> + * Power Domain flags
> + */
> +#define PD_CPU BIT(0) /* Area contains main CPU core */
> +#define PD_SCU BIT(1) /* Area contains SCU and L2 cache */
> +#define PD_NO_CR BIT(2) /* Area lacks PWR{ON,OFF}CR registers */
> +
> +#define PD_BUSY BIT(3) /* Busy, for internal use only */
> +
> +#define PD_CPU_CR PD_CPU /* CPU area has CR (R-Car H1) */
> +#define PD_CPU_NOCR PD_CPU | PD_NO_CR /* CPU area lacks CR (R-Car Gen2/3)
> */ +#define PD_ALWAYS_ON PD_NO_CR /* Always-on area */
> +
> +
> +/*
> + * Description of a Power Area
> + */
> +
> +struct rcar_sysc_area {
> + const char *name;
> + u16 chan_offs; /* Offset of PWRSR register for this area */
> + u8 chan_bit; /* Bit in PWR* (except for PWRUP in PWRSR) */
> + u8 isr_bit; /* Bit in SYSCI*R */
> + int parent; /* -1 if none */
> + unsigned int flags; /* See PD_* */
> +};
> +
> +
> +/*
> + * SoC-specific Power Area Description
> + */
> +
> +struct rcar_sysc_info {
> + const struct rcar_sysc_area *areas;
> + unsigned int num_areas;
> +};
> +
> +#endif /* __SOC_RENESAS_RCAR_SYSC_H__ */

--
Regards,

Laurent Pinchart