From 9086b64ca07166b1e72b29ad04e3fe2a483c5454 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Fri, 25 Apr 2025 08:49:32 +0200 Subject: [PATCH] power-domain: Add support for refcounting (again) It is very surprising that such an uclass, specifically designed to handle resources that may be shared by different devices, is not keeping the count of the number of times a power domain has been enabled/disabled to avoid shutting it down unexpectedly or disabling it several times. Doing this causes troubles on eg. i.MX8MP because disabling power domains can be done in recursive loops were the same power domain disabled up to 4 times in a row. PGCs seem to have tight FSM internal timings to respect and it is easy to produce a race condition that puts the power domains in an unstable state, leading to ADB400 errors and later crashes in Linux. Some drivers implement their own mechanism for that, but it is probably best to add this feature in the uclass and share the common code across drivers. In order to avoid breaking existing drivers, refcounting is only enabled if the number of subdomains a device node supports is explicitly set in the probe function. ->xlate() callbacks will return the power domain ID which is then being used as the array index to reach the correct refcounter. As we do not want to break existing users while stile getting interesting error codes, the implementation is split between: - a low-level helper reporting error codes if the requested transition could not be operated, - a higher-level helper ignoring the "non error" codes, like EALREADY and EBUSY. CI tests using power domains are slightly updated to make sure the count of on/off calls is even and the results match what we *now* expect. They are also extended to test the low-level functions. Signed-off-by: Miquel Raynal --- arch/sandbox/include/asm/power-domain.h | 2 + drivers/firmware/scmi/sandbox-scmi_devices.c | 1 + drivers/power/domain/power-domain-uclass.c | 90 +++++++++++++++++-- .../power/domain/sandbox-power-domain-test.c | 15 ++++ drivers/power/domain/sandbox-power-domain.c | 4 + include/power-domain.h | 69 ++++++++++++-- test/dm/power-domain.c | 11 ++- 7 files changed, 177 insertions(+), 15 deletions(-) diff --git a/arch/sandbox/include/asm/power-domain.h b/arch/sandbox/include/asm/power-domain.h index 4d5e861dbce..3b0717f8fa0 100644 --- a/arch/sandbox/include/asm/power-domain.h +++ b/arch/sandbox/include/asm/power-domain.h @@ -13,6 +13,8 @@ int sandbox_power_domain_query(struct udevice *dev, unsigned long id); int sandbox_power_domain_test_get(struct udevice *dev); int sandbox_power_domain_test_on(struct udevice *dev); int sandbox_power_domain_test_off(struct udevice *dev); +int sandbox_power_domain_test_on_ll(struct udevice *dev); +int sandbox_power_domain_test_off_ll(struct udevice *dev); int sandbox_power_domain_test_free(struct udevice *dev); #endif diff --git a/drivers/firmware/scmi/sandbox-scmi_devices.c b/drivers/firmware/scmi/sandbox-scmi_devices.c index 96c2922b067..9f253b0fd40 100644 --- a/drivers/firmware/scmi/sandbox-scmi_devices.c +++ b/drivers/firmware/scmi/sandbox-scmi_devices.c @@ -163,4 +163,5 @@ U_BOOT_DRIVER(sandbox_scmi_devices) = { .priv_auto = sizeof(struct sandbox_scmi_device_priv), .remove = sandbox_scmi_devices_remove, .probe = sandbox_scmi_devices_probe, + .flags = DM_FLAG_DEFAULT_PD_CTRL_OFF, }; diff --git a/drivers/power/domain/power-domain-uclass.c b/drivers/power/domain/power-domain-uclass.c index 938bd8cbc9f..d9fa8ad4bd2 100644 --- a/drivers/power/domain/power-domain-uclass.c +++ b/drivers/power/domain/power-domain-uclass.c @@ -12,6 +12,10 @@ #include #include +struct power_domain_priv { + int *on_count; +}; + static inline struct power_domain_ops *power_domain_dev_ops(struct udevice *dev) { return (struct power_domain_ops *)dev->driver->ops; @@ -107,22 +111,67 @@ int power_domain_free(struct power_domain *power_domain) return ops->rfree ? ops->rfree(power_domain) : 0; } -int power_domain_on(struct power_domain *power_domain) +int power_domain_on_lowlevel(struct power_domain *power_domain) { + struct power_domain_priv *priv = dev_get_uclass_priv(power_domain->dev); + struct power_domain_plat *plat = dev_get_uclass_plat(power_domain->dev); struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev); + int *on_count = plat->subdomains ? &priv->on_count[power_domain->id] : NULL; + int ret; - debug("%s(power_domain=%p)\n", __func__, power_domain); + /* Refcounting is not enabled on all drivers by default */ + if (on_count) { + debug("Enable power domain %s.%ld: %d -> %d (%s)\n", + power_domain->dev->name, power_domain->id, *on_count, *on_count + 1, + (((*on_count + 1) > 1) ? "EALREADY" : "todo")); + + (*on_count)++; + if (*on_count > 1) + return -EALREADY; + } + + ret = ops->on ? ops->on(power_domain) : 0; + if (ret) { + if (on_count) + (*on_count)--; + return ret; + } - return ops->on ? ops->on(power_domain) : 0; + return 0; } -int power_domain_off(struct power_domain *power_domain) +int power_domain_off_lowlevel(struct power_domain *power_domain) { + struct power_domain_priv *priv = dev_get_uclass_priv(power_domain->dev); + struct power_domain_plat *plat = dev_get_uclass_plat(power_domain->dev); struct power_domain_ops *ops = power_domain_dev_ops(power_domain->dev); + int *on_count = plat->subdomains ? &priv->on_count[power_domain->id] : NULL; + int ret; - debug("%s(power_domain=%p)\n", __func__, power_domain); + /* Refcounting is not enabled on all drivers by default */ + if (on_count) { + debug("Disable power domain %s.%ld: %d -> %d (%s%s)\n", + power_domain->dev->name, power_domain->id, *on_count, *on_count - 1, + (((*on_count) <= 0) ? "EALREADY" : ""), + (((*on_count - 1) > 0) ? "BUSY" : "todo")); + + if (*on_count <= 0) + return -EALREADY; + + (*on_count)--; + if (*on_count > 0) + return -EBUSY; + } + + ret = ops->off ? ops->off(power_domain) : 0; + if (ret) { + if (on_count) + (*on_count)++; - return ops->off ? ops->off(power_domain) : 0; + return ret; + } + + return 0; } #if CONFIG_IS_ENABLED(OF_REAL) @@ -177,7 +226,36 @@ int dev_power_domain_off(struct udevice *dev) } #endif /* OF_REAL */ +static int power_domain_post_probe(struct udevice *dev) +{ + struct power_domain_priv *priv = dev_get_uclass_priv(dev); + struct power_domain_plat *plat = dev_get_uclass_plat(dev); + + if (plat->subdomains) { + priv->on_count = calloc(sizeof(int), plat->subdomains); + if (!priv->on_count) + return -ENOMEM; + } + + return 0; +} + +static int power_domain_pre_remove(struct udevice *dev) +{ + struct power_domain_priv *priv = dev_get_uclass_priv(dev); + struct power_domain_plat *plat = dev_get_uclass_plat(dev); + + if (plat->subdomains) + free(priv->on_count); + + return 0; +} + UCLASS_DRIVER(power_domain) = { .id = UCLASS_POWER_DOMAIN, .name = "power_domain", + .post_probe = power_domain_post_probe, + .pre_remove = power_domain_pre_remove, + .per_device_auto = sizeof(struct power_domain_priv), + .per_device_plat_auto = sizeof(struct power_domain_plat), }; diff --git a/drivers/power/domain/sandbox-power-domain-test.c b/drivers/power/domain/sandbox-power-domain-test.c index 08c15ef342b..df063001f51 100644 --- a/drivers/power/domain/sandbox-power-domain-test.c +++ b/drivers/power/domain/sandbox-power-domain-test.c @@ -34,6 +34,20 @@ int sandbox_power_domain_test_off(struct udevice *dev) return power_domain_off(&sbrt->pd); } +int sandbox_power_domain_test_on_ll(struct udevice *dev) +{ + struct sandbox_power_domain_test *sbrt = dev_get_priv(dev); + + return power_domain_on_lowlevel(&sbrt->pd); +} + +int sandbox_power_domain_test_off_ll(struct udevice *dev) +{ + struct sandbox_power_domain_test *sbrt = dev_get_priv(dev); + + return power_domain_off_lowlevel(&sbrt->pd); +} + int sandbox_power_domain_test_free(struct udevice *dev) { struct sandbox_power_domain_test *sbrt = dev_get_priv(dev); @@ -51,4 +65,5 @@ U_BOOT_DRIVER(sandbox_power_domain_test) = { .id = UCLASS_MISC, .of_match = sandbox_power_domain_test_ids, .priv_auto = sizeof(struct sandbox_power_domain_test), + .flags = DM_FLAG_DEFAULT_PD_CTRL_OFF, }; diff --git a/drivers/power/domain/sandbox-power-domain.c b/drivers/power/domain/sandbox-power-domain.c index 9dd490b14a3..a8031657638 100644 --- a/drivers/power/domain/sandbox-power-domain.c +++ b/drivers/power/domain/sandbox-power-domain.c @@ -64,8 +64,12 @@ static int sandbox_power_domain_bind(struct udevice *dev) static int sandbox_power_domain_probe(struct udevice *dev) { + struct power_domain_plat *plat = dev_get_uclass_plat(dev); + debug("%s(dev=%p)\n", __func__, dev); + plat->subdomains = 1; + return 0; } diff --git a/include/power-domain.h b/include/power-domain.h index 18525073e5e..7fd2c5e365b 100644 --- a/include/power-domain.h +++ b/include/power-domain.h @@ -65,6 +65,15 @@ struct power_domain { void *priv; }; +/** + * struct power_domain_plat - Per device accessible structure + * @subdomains: Number of subdomains covered by this device, required + * for refcounting + */ +struct power_domain_plat { + int subdomains; +}; + /** * power_domain_get - Get/request the power domain for a device. * @@ -147,37 +156,81 @@ static inline int power_domain_free(struct power_domain *power_domain) #endif /** - * power_domain_on - Enable power to a power domain. + * power_domain_on_lowlevel - Enable power to a power domain (with refcounting) * * @power_domain: A power domain struct that was previously successfully * requested by power_domain_get(). - * Return: 0 if OK, or a negative error code. + * Return: 0 if the transition has been performed correctly, + * -EALREADY if the domain is already on, + * a negative error code otherwise. */ #if CONFIG_IS_ENABLED(POWER_DOMAIN) -int power_domain_on(struct power_domain *power_domain); +int power_domain_on_lowlevel(struct power_domain *power_domain); #else -static inline int power_domain_on(struct power_domain *power_domain) +static inline int power_domain_on_lowlevel(struct power_domain *power_domain) { return -ENOSYS; } #endif /** - * power_domain_off - Disable power to a power domain. + * power_domain_on - Enable power to a power domain (ignores the actual state + * of the power domain) * * @power_domain: A power domain struct that was previously successfully * requested by power_domain_get(). - * Return: 0 if OK, or a negative error code. + * Return: a negative error code upon error during the transition, 0 otherwise. + */ +static inline int power_domain_on(struct power_domain *power_domain) +{ + int ret; + + ret = power_domain_on_lowlevel(power_domain); + if (ret == -EALREADY) + ret = 0; + + return ret; +} + +/** + * power_domain_off_lowlevel - Disable power to a power domain (with refcounting) + * + * @power_domain: A power domain struct that was previously successfully + * requested by power_domain_get(). + * Return: 0 if the transition has been performed correctly, + * -EALREADY if the domain is already off, + * -EBUSY if another device is keeping the domain on (but the refcounter + * is decremented), + * a negative error code otherwise. */ #if CONFIG_IS_ENABLED(POWER_DOMAIN) -int power_domain_off(struct power_domain *power_domain); +int power_domain_off_lowlevel(struct power_domain *power_domain); #else -static inline int power_domain_off(struct power_domain *power_domain) +static inline int power_domain_off_lowlevel(struct power_domain *power_domain) { return -ENOSYS; } #endif +/** + * power_domain_off - Disable power to a power domain (ignores the actual state + * of the power domain) + * + * @power_domain: A power domain struct that was previously successfully + * requested by power_domain_get(). + * Return: a negative error code upon error during the transition, 0 otherwise. + */ +static inline int power_domain_off(struct power_domain *power_domain) +{ + int ret; + + ret = power_domain_off_lowlevel(power_domain); + if (ret == -EALREADY || ret == -EBUSY) + ret = 0; + + return ret; +} + /** * dev_power_domain_on - Enable power domains for a device . * diff --git a/test/dm/power-domain.c b/test/dm/power-domain.c index 896cf5b2ae9..1002d831764 100644 --- a/test/dm/power-domain.c +++ b/test/dm/power-domain.c @@ -27,17 +27,26 @@ static int dm_test_power_domain(struct unit_test_state *uts) ut_assertok(uclass_get_device_by_name(UCLASS_MISC, "power-domain-test", &dev_test)); - ut_asserteq(1, sandbox_power_domain_query(dev_power_domain, + ut_asserteq(0, sandbox_power_domain_query(dev_power_domain, TEST_POWER_DOMAIN)); ut_assertok(sandbox_power_domain_test_get(dev_test)); ut_assertok(sandbox_power_domain_test_on(dev_test)); ut_asserteq(0, sandbox_power_domain_query(dev_power_domain, 0)); + ut_asserteq(1, sandbox_power_domain_query(dev_power_domain, + TEST_POWER_DOMAIN)); + ut_asserteq(-EALREADY, sandbox_power_domain_test_on_ll(dev_test)); + ut_asserteq(1, sandbox_power_domain_query(dev_power_domain, + TEST_POWER_DOMAIN)); + ut_asserteq(-EBUSY, sandbox_power_domain_test_off_ll(dev_test)); ut_asserteq(1, sandbox_power_domain_query(dev_power_domain, TEST_POWER_DOMAIN)); ut_assertok(sandbox_power_domain_test_off(dev_test)); ut_asserteq(0, sandbox_power_domain_query(dev_power_domain, 0)); + ut_asserteq(0, sandbox_power_domain_query(dev_power_domain, + TEST_POWER_DOMAIN)); + ut_asserteq(-EALREADY, sandbox_power_domain_test_off_ll(dev_test)); ut_asserteq(0, sandbox_power_domain_query(dev_power_domain, TEST_POWER_DOMAIN)); -- 2.39.5