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authorMarc Zyngier <Marc.Zyngier@arm.com>2015-09-28 15:49:12 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-10-01 02:18:38 +0200
commite647b532275bb357e87272e052fccf5fcdb36a17 (patch)
treeffb3a3d9e302e5e76cc2466f75c67d097fdbe504 /drivers
parent233782495f161341a82aa933b42b35c94077bd65 (diff)
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ACPI: Add early device probing infrastructure
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> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/acpi/scan.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d1ce377db3e9..1d6b55a6f501 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);
+ 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;
+}