Messages in this thread | | | Subject | Re: [PATCH v3 1/7] acpi: Add early device probing infrastructure | From | Daniel Lezcano <> | Date | Tue, 29 Sep 2015 06:30:52 +0200 |
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Hi Marc,
On 09/28/2015 04:49 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_table() is provided, taking an identifier for > a set of acpi_prove_entries, and iterating over the registered > entries. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > drivers/acpi/scan.c | 39 +++++++++++++++++++++++ > include/asm-generic/vmlinux.lds.h | 10 ++++++ > include/linux/acpi.h | 66 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 115 insertions(+) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index f834b8c..daf9fc8 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -1913,3 +1913,42 @@ int __init acpi_scan_init(void) > mutex_unlock(&acpi_scan_lock); > return result; > } > + > +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->subtable_valid || ape->subtable_valid(header, ape)) > + if (!ape->probe_subtbl(header, end)) > + acpi_probe_count++; > + > + return 0; > +} > + > +int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr) > +{ > + int count = 0; > + > + if (acpi_disabled) > + return 0; > + > + spin_lock(&acpi_probe_lock); > + for (ape = ap_head; nr; ape++, nr--) { > + if (ACPI_COMPARE_NAME(ACPI_SIG_MADT, ape->id)) { > + acpi_probe_count = 0; > + acpi_table_parse_madt(ape->type, acpi_match_madt, 0);
Isn't supposed 'acpi_table_parse_madt' to return the count ? and shouldn't the return code be checked ?
> + count += acpi_probe_count; > + } else { > + int res; > + res = acpi_table_parse(ape->id, ape->probe_table); > + if (!res) > + count++; > + } > + } > + spin_unlock(&acpi_probe_lock); > + > + return count; > +}
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