| Message ID | 1441386412-8139-2-git-send-email-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
[+M.Salter] On Fri, Sep 04, 2015 at 06:06:48PM +0100, Marc Zyngier wrote: > IRQ controllers and timers are the two types of device the kernel > requires before being able to use the device driver model. > > ACPI so far lacks a proper probing infrastructure similar to the one > we have with DT, where we're able to declare IRQ chips and > clocksources inside the driver code, and let the core code pick it up > and call us back on a match. This leads to all kind of really ugly > hacks all over the arm64 code and even in the ACPI layer. > > In order to allow some basic probing based on the ACPI tables, > introduce "struct acpi_probe_entry" which contains just enough > data and callbacks to match a table, an optional subtable, and > call a probe function. A driver can, at build time, register itself > and expect being called if the right entry exists in the ACPI > table. > > A acpi_probe_device_init() is provided, taking an ACPI table > identifier, and iterating over the registered entries. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > drivers/acpi/scan.c | 41 ++++++++++++++++++++++++++++ > include/asm-generic/vmlinux.lds.h | 11 ++++++++ > include/linux/acpi.h | 56 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 108 insertions(+) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index ec25635..9e920ec 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -2793,3 +2793,44 @@ int __init acpi_scan_init(void) > mutex_unlock(&acpi_scan_lock); > return result; > } > + > +static const struct acpi_probe_entry device_acpi_probe_end > + __used __section(__device_acpi_probe_table_end); > +extern struct acpi_probe_entry __device_acpi_probe_table[]; > +static struct acpi_probe_entry *ape; > +static int acpi_probe_count; > +static DEFINE_SPINLOCK(acpi_probe_lock); > + > +static int __init acpi_match_madt(struct acpi_subtable_header *header, > + const unsigned long end) > +{ > + if (!ape->validate_subtbl || ape->validate_subtbl(header, ape)) > + if (!ape->probe_subtbl(header, end)) > + acpi_probe_count++; > + > + return 0; > +} > + > +int __init acpi_probe_device_table(const char *id) > +{ > + int count = 0; > + > + if (acpi_disabled) > + return 0; > + > + spin_lock(&acpi_probe_lock); > + for (ape = __device_acpi_probe_table; ape->probe_table; ape++) { > + if (!ACPI_COMPARE_NAME(id, ape->id)) > + continue; > + if (ACPI_COMPARE_NAME(ACPI_SIG_MADT, ape->id)) { > + acpi_probe_count = 0; > + acpi_table_parse_madt(ape->type, acpi_match_madt, 0); > + count += acpi_probe_count; > + } else { > + count = acpi_table_parse(ape->id, ape->probe_table); > + } > + } > + spin_unlock(&acpi_probe_lock); > + > + return count; > +} We should add a mechanism to prevent re-parsing the same entries multiple times (in case this function is called with the same signature multiple times). We could create a separate table of device entries, per-subsystem, that we want to parse (irqchip specific table, timers, etc.) instead of adding all the devices to the same table (ie linker section), you can do this already with the current patchset by just choosing different table names as DT does. We may also want to extend this set so that it can be used to parse the same table, same subtype multiple times at different stages in the boot path (but let's first see if it is a) really needed b) feasible). Basically it is to avoid parsing the MADT multiple times: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/340267.html Those can be extensions to the current patchset (because basically they are not real issues at present), it is just a heads-up. Thanks for putting it together ! Lorenzo > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index 8bd374d..875397a 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -181,6 +181,16 @@ > #define CPUIDLE_METHOD_OF_TABLES() OF_TABLE(CONFIG_CPU_IDLE, cpuidle_method) > #define EARLYCON_OF_TABLES() OF_TABLE(CONFIG_SERIAL_EARLYCON, earlycon) > > +#ifdef CONFIG_ACPI > +#define ACPI_PROBE_TABLE(name) \ > + . = ALIGN(8); \ > + VMLINUX_SYMBOL(__##name##_acpi_probe_table) = .; \ > + *(__##name##_acpi_probe_table) \ > + *(__##name##_acpi_probe_table_end) > +#else > +#define ACPI_PROBE_TABLE(name) > +#endif > + > #define KERNEL_DTB() \ > STRUCT_ALIGN(); \ > VMLINUX_SYMBOL(__dtb_start) = .; \ > @@ -516,6 +526,7 @@ > CPUIDLE_METHOD_OF_TABLES() \ > KERNEL_DTB() \ > IRQCHIP_OF_MATCH_TABLE() \ > + ACPI_PROBE_TABLE(device) \ > EARLYCON_TABLE() \ > EARLYCON_OF_TABLES() > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index d2445fa..bf6dfb9 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -763,6 +763,52 @@ int acpi_dev_prop_read(struct acpi_device *adev, const char *propname, > > struct acpi_device *acpi_get_next_child(struct device *dev, > struct acpi_device *child); > + > +struct acpi_probe_entry; > +typedef bool (*acpi_probe_entry_validate_subtbl)(struct acpi_subtable_header *, > + struct acpi_probe_entry *); > + > +#define ACPI_TABLE_ID_LEN 5 > + > +/** > + * struct acpi_probe_entry - boot-time probing entry > + * @id: ACPI table name > + * @type: Optional subtable type to match > + * (if @id contains subtables) > + * @validate_subtbl: Optional callback to check the validity of > + * the subtable > + * @probe_table: Callback to the driver being probed when table > + * match is successful > + * @probe_subtbl: Callback to the driver being probed when table and > + * subtable match (and optionnal callback is successful) > + * @driver_data: Sideband data provided back to the driver > + */ > +struct acpi_probe_entry { > + __u8 id[ACPI_TABLE_ID_LEN]; > + __u8 type; > + acpi_probe_entry_validate_subtbl validate_subtbl; > + union { > + acpi_tbl_table_handler probe_table; > + acpi_tbl_entry_handler probe_subtbl; > + }; > + kernel_ulong_t driver_data; > +}; > + > +#define ACPI_DECLARE(table, name, table_id, subtable, valid, data, fn) \ > + static const struct acpi_probe_entry __acpi_probe_##name \ > + __used __section(__##table##_acpi_probe_table) \ > + = { \ > + .id = table_id, \ > + .type = subtable, \ > + .validate_subtbl = valid, \ > + .probe_table = (acpi_tbl_table_handler)fn, \ > + .driver_data = data, \ > + } > + > +#define DEVICE_ACPI_DECLARE(name, table_id, fn) \ > + ACPI_DECLARE(device, name, table_id, 0, NULL, 0, fn) > + > +int acpi_probe_device_table(const char *id); > #else > static inline int acpi_dev_get_property(struct acpi_device *adev, > const char *name, acpi_object_type type, > @@ -813,6 +859,16 @@ static inline struct acpi_device *acpi_get_next_child(struct device *dev, > return NULL; > } > > +#define ACPI_DECLARE(table, name, table_id, subtable, validate, data, fn) \ > + static const void * __acpi_table_##name[] \ > + __attribute__((unused)) \ > + = { (void *) table_id, \ > + (void *) subtable, \ > + (void *) valid, \ > + (void *) fn, \ > + (void *) data } > + > +static inline int acpi_probe_device_table(const char *id) { return 0; } > #endif > > #endif /*_LINUX_ACPI_H*/ > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/09/15 17:00, Lorenzo Pieralisi wrote: > [+M.Salter] > > On Fri, Sep 04, 2015 at 06:06:48PM +0100, Marc Zyngier wrote: >> IRQ controllers and timers are the two types of device the kernel >> requires before being able to use the device driver model. >> >> ACPI so far lacks a proper probing infrastructure similar to the one >> we have with DT, where we're able to declare IRQ chips and >> clocksources inside the driver code, and let the core code pick it up >> and call us back on a match. This leads to all kind of really ugly >> hacks all over the arm64 code and even in the ACPI layer. >> >> In order to allow some basic probing based on the ACPI tables, >> introduce "struct acpi_probe_entry" which contains just enough >> data and callbacks to match a table, an optional subtable, and >> call a probe function. A driver can, at build time, register itself >> and expect being called if the right entry exists in the ACPI >> table. >> >> A acpi_probe_device_init() is provided, taking an ACPI table >> identifier, and iterating over the registered entries. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> drivers/acpi/scan.c | 41 ++++++++++++++++++++++++++++ >> include/asm-generic/vmlinux.lds.h | 11 ++++++++ >> include/linux/acpi.h | 56 +++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 108 insertions(+) >> >> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c >> index ec25635..9e920ec 100644 >> --- a/drivers/acpi/scan.c >> +++ b/drivers/acpi/scan.c >> @@ -2793,3 +2793,44 @@ int __init acpi_scan_init(void) >> mutex_unlock(&acpi_scan_lock); >> return result; >> } >> + >> +static const struct acpi_probe_entry device_acpi_probe_end >> + __used __section(__device_acpi_probe_table_end); >> +extern struct acpi_probe_entry __device_acpi_probe_table[]; >> +static struct acpi_probe_entry *ape; >> +static int acpi_probe_count; >> +static DEFINE_SPINLOCK(acpi_probe_lock); >> + >> +static int __init acpi_match_madt(struct acpi_subtable_header *header, >> + const unsigned long end) >> +{ >> + if (!ape->validate_subtbl || ape->validate_subtbl(header, ape)) >> + if (!ape->probe_subtbl(header, end)) >> + acpi_probe_count++; >> + >> + return 0; >> +} >> + >> +int __init acpi_probe_device_table(const char *id) >> +{ >> + int count = 0; >> + >> + if (acpi_disabled) >> + return 0; >> + >> + spin_lock(&acpi_probe_lock); >> + for (ape = __device_acpi_probe_table; ape->probe_table; ape++) { >> + if (!ACPI_COMPARE_NAME(id, ape->id)) >> + continue; >> + if (ACPI_COMPARE_NAME(ACPI_SIG_MADT, ape->id)) { >> + acpi_probe_count = 0; >> + acpi_table_parse_madt(ape->type, acpi_match_madt, 0); >> + count += acpi_probe_count; >> + } else { >> + count = acpi_table_parse(ape->id, ape->probe_table); >> + } >> + } >> + spin_unlock(&acpi_probe_lock); >> + >> + return count; >> +} > > We should add a mechanism to prevent re-parsing the same entries > multiple times (in case this function is called with the same > signature multiple times). We could create a separate table of device > entries, per-subsystem, that we want to parse (irqchip specific table, > timers, etc.) instead of adding all the devices to the same table (ie > linker section), you can do this already with the current patchset by > just choosing different table names as DT does. Yeah, my initial approach was to have multiple tables, but I ended up deciding against it because nothing required it so far, and I wanted to avoid the over-engineered syndrome. Also, it could be useful to flag entries that have been successfully probed to ensure we don't try them again. Though having separate tables would probably greatly reduce the usefulness of this. > We may also want to extend this set so that it can be used to parse the > same table, same subtype multiple times at different stages in the boot > path (but let's first see if it is a) really needed b) feasible). > > Basically it is to avoid parsing the MADT multiple times: > http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/340267.html > > Those can be extensions to the current patchset (because basically > they are not real issues at present), it is just a heads-up. I'll see if I can whip that up by the end of the week - the PMU stuff is definitely interesting. Thanks, M.
On Friday, September 04, 2015 06:06:48 PM Marc Zyngier wrote: > IRQ controllers and timers are the two types of device the kernel > requires before being able to use the device driver model. > > ACPI so far lacks a proper probing infrastructure similar to the one > we have with DT, where we're able to declare IRQ chips and > clocksources inside the driver code, and let the core code pick it up > and call us back on a match. This leads to all kind of really ugly > hacks all over the arm64 code and even in the ACPI layer. > > In order to allow some basic probing based on the ACPI tables, > introduce "struct acpi_probe_entry" which contains just enough > data and callbacks to match a table, an optional subtable, and > call a probe function. A driver can, at build time, register itself > and expect being called if the right entry exists in the ACPI > table. > > A acpi_probe_device_init() is provided, taking an ACPI table > identifier, and iterating over the registered entries. What about things that are provided by the ACPI namespace (eg. via _MAT) rather than in static tables? Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/09/15 22:29, Rafael J. Wysocki wrote: > On Friday, September 04, 2015 06:06:48 PM Marc Zyngier wrote: >> IRQ controllers and timers are the two types of device the kernel >> requires before being able to use the device driver model. >> >> ACPI so far lacks a proper probing infrastructure similar to the one >> we have with DT, where we're able to declare IRQ chips and >> clocksources inside the driver code, and let the core code pick it up >> and call us back on a match. This leads to all kind of really ugly >> hacks all over the arm64 code and even in the ACPI layer. >> >> In order to allow some basic probing based on the ACPI tables, >> introduce "struct acpi_probe_entry" which contains just enough >> data and callbacks to match a table, an optional subtable, and >> call a probe function. A driver can, at build time, register itself >> and expect being called if the right entry exists in the ACPI >> table. >> >> A acpi_probe_device_init() is provided, taking an ACPI table >> identifier, and iterating over the registered entries. > > What about things that are provided by the ACPI namespace (eg. via _MAT) rather > than in static tables? By the time we get to process non-static tables, the whole probing infrastructure (including the ACPI interpreter) should be up and running. I'm not seeing this stuff as a replacement for more dynamic things - quite the opposite. It is only to be used for early bring-up. Thanks, M.
On 09/08/2015 05:57 PM, Marc Zyngier wrote: > On 07/09/15 22:29, Rafael J. Wysocki wrote: >> On Friday, September 04, 2015 06:06:48 PM Marc Zyngier wrote: >>> IRQ controllers and timers are the two types of device the kernel >>> requires before being able to use the device driver model. >>> >>> ACPI so far lacks a proper probing infrastructure similar to the one >>> we have with DT, where we're able to declare IRQ chips and >>> clocksources inside the driver code, and let the core code pick it up >>> and call us back on a match. This leads to all kind of really ugly >>> hacks all over the arm64 code and even in the ACPI layer. >>> >>> In order to allow some basic probing based on the ACPI tables, >>> introduce "struct acpi_probe_entry" which contains just enough >>> data and callbacks to match a table, an optional subtable, and >>> call a probe function. A driver can, at build time, register itself >>> and expect being called if the right entry exists in the ACPI >>> table. >>> >>> A acpi_probe_device_init() is provided, taking an ACPI table >>> identifier, and iterating over the registered entries. >> >> What about things that are provided by the ACPI namespace (eg. via _MAT) rather >> than in static tables? > > By the time we get to process non-static tables, the whole probing > infrastructure (including the ACPI interpreter) should be up and > running. I'm not seeing this stuff as a replacement for more dynamic > things - quite the opposite. It is only to be used for early bring-up. Yes, this framework is for static tables and used at boot time, sometimes quite early, which is before acpi_early_init(). But for _MAT (which is used for dynamic device configuration), it's really a good question, I think _MAT is mainly for CPU hotplug, and it's not related to this framework (for GIC init and clock source). To hot add/remove a whole ARM SoC with _MAT, I think we need more time to make the spec ready first, that's long term work, and agian it's nothing to do with this infrastructure if I understand correctly :) Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index ec25635..9e920ec 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2793,3 +2793,44 @@ int __init acpi_scan_init(void) mutex_unlock(&acpi_scan_lock); return result; } + +static const struct acpi_probe_entry device_acpi_probe_end + __used __section(__device_acpi_probe_table_end); +extern struct acpi_probe_entry __device_acpi_probe_table[]; +static struct acpi_probe_entry *ape; +static int acpi_probe_count; +static DEFINE_SPINLOCK(acpi_probe_lock); + +static int __init acpi_match_madt(struct acpi_subtable_header *header, + const unsigned long end) +{ + if (!ape->validate_subtbl || ape->validate_subtbl(header, ape)) + if (!ape->probe_subtbl(header, end)) + acpi_probe_count++; + + return 0; +} + +int __init acpi_probe_device_table(const char *id) +{ + int count = 0; + + if (acpi_disabled) + return 0; + + spin_lock(&acpi_probe_lock); + for (ape = __device_acpi_probe_table; ape->probe_table; ape++) { + if (!ACPI_COMPARE_NAME(id, ape->id)) + continue; + if (ACPI_COMPARE_NAME(ACPI_SIG_MADT, ape->id)) { + acpi_probe_count = 0; + acpi_table_parse_madt(ape->type, acpi_match_madt, 0); + count += acpi_probe_count; + } else { + count = acpi_table_parse(ape->id, ape->probe_table); + } + } + spin_unlock(&acpi_probe_lock); + + return count; +} diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 8bd374d..875397a 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -181,6 +181,16 @@ #define CPUIDLE_METHOD_OF_TABLES() OF_TABLE(CONFIG_CPU_IDLE, cpuidle_method) #define EARLYCON_OF_TABLES() OF_TABLE(CONFIG_SERIAL_EARLYCON, earlycon) +#ifdef CONFIG_ACPI +#define ACPI_PROBE_TABLE(name) \ + . = ALIGN(8); \ + VMLINUX_SYMBOL(__##name##_acpi_probe_table) = .; \ + *(__##name##_acpi_probe_table) \ + *(__##name##_acpi_probe_table_end) +#else +#define ACPI_PROBE_TABLE(name) +#endif + #define KERNEL_DTB() \ STRUCT_ALIGN(); \ VMLINUX_SYMBOL(__dtb_start) = .; \ @@ -516,6 +526,7 @@ CPUIDLE_METHOD_OF_TABLES() \ KERNEL_DTB() \ IRQCHIP_OF_MATCH_TABLE() \ + ACPI_PROBE_TABLE(device) \ EARLYCON_TABLE() \ EARLYCON_OF_TABLES() diff --git a/include/linux/acpi.h b/include/linux/acpi.h index d2445fa..bf6dfb9 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -763,6 +763,52 @@ int acpi_dev_prop_read(struct acpi_device *adev, const char *propname, struct acpi_device *acpi_get_next_child(struct device *dev, struct acpi_device *child); + +struct acpi_probe_entry; +typedef bool (*acpi_probe_entry_validate_subtbl)(struct acpi_subtable_header *, + struct acpi_probe_entry *); + +#define ACPI_TABLE_ID_LEN 5 + +/** + * struct acpi_probe_entry - boot-time probing entry + * @id: ACPI table name + * @type: Optional subtable type to match + * (if @id contains subtables) + * @validate_subtbl: Optional callback to check the validity of + * the subtable + * @probe_table: Callback to the driver being probed when table + * match is successful + * @probe_subtbl: Callback to the driver being probed when table and + * subtable match (and optionnal callback is successful) + * @driver_data: Sideband data provided back to the driver + */ +struct acpi_probe_entry { + __u8 id[ACPI_TABLE_ID_LEN]; + __u8 type; + acpi_probe_entry_validate_subtbl validate_subtbl; + union { + acpi_tbl_table_handler probe_table; + acpi_tbl_entry_handler probe_subtbl; + }; + kernel_ulong_t driver_data; +}; + +#define ACPI_DECLARE(table, name, table_id, subtable, valid, data, fn) \ + static const struct acpi_probe_entry __acpi_probe_##name \ + __used __section(__##table##_acpi_probe_table) \ + = { \ + .id = table_id, \ + .type = subtable, \ + .validate_subtbl = valid, \ + .probe_table = (acpi_tbl_table_handler)fn, \ + .driver_data = data, \ + } + +#define DEVICE_ACPI_DECLARE(name, table_id, fn) \ + ACPI_DECLARE(device, name, table_id, 0, NULL, 0, fn) + +int acpi_probe_device_table(const char *id); #else static inline int acpi_dev_get_property(struct acpi_device *adev, const char *name, acpi_object_type type, @@ -813,6 +859,16 @@ static inline struct acpi_device *acpi_get_next_child(struct device *dev, return NULL; } +#define ACPI_DECLARE(table, name, table_id, subtable, validate, data, fn) \ + static const void * __acpi_table_##name[] \ + __attribute__((unused)) \ + = { (void *) table_id, \ + (void *) subtable, \ + (void *) valid, \ + (void *) fn, \ + (void *) data } + +static inline int acpi_probe_device_table(const char *id) { return 0; } #endif #endif /*_LINUX_ACPI_H*/
IRQ controllers and timers are the two types of device the kernel requires before being able to use the device driver model. ACPI so far lacks a proper probing infrastructure similar to the one we have with DT, where we're able to declare IRQ chips and clocksources inside the driver code, and let the core code pick it up and call us back on a match. This leads to all kind of really ugly hacks all over the arm64 code and even in the ACPI layer. In order to allow some basic probing based on the ACPI tables, introduce "struct acpi_probe_entry" which contains just enough data and callbacks to match a table, an optional subtable, and call a probe function. A driver can, at build time, register itself and expect being called if the right entry exists in the ACPI table. A acpi_probe_device_init() is provided, taking an ACPI table identifier, and iterating over the registered entries. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- drivers/acpi/scan.c | 41 ++++++++++++++++++++++++++++ include/asm-generic/vmlinux.lds.h | 11 ++++++++ include/linux/acpi.h | 56 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+)