From 02a6de7789ee1fc14c879dd2e7cbaf6fbc4f5231 Mon Sep 17 00:00:00 2001
From: Andrew Turner <andrew@FreeBSD.org>
Date: Thu, 19 Nov 2020 09:26:51 +0000
Subject: [PATCH] Fall back to use the GICR address from the generic interrupt
 struct

When there is no ACPI redistributor sub-table in the MADT we need to
fall back to use the GICR base address from the GIC CPU interface
structure.

Handle this fallback when adding memory to the device and when counting
the number of redistributors.

PR:		251171
Reported by:	Andrey Fesenko <f0andrey_gmail.com>
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D27247
---
 sys/arm64/arm64/gic_v3_acpi.c | 47 +++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/sys/arm64/arm64/gic_v3_acpi.c b/sys/arm64/arm64/gic_v3_acpi.c
index ad4dfd92eafa..e73e37f8e851 100644
--- a/sys/arm64/arm64/gic_v3_acpi.c
+++ b/sys/arm64/arm64/gic_v3_acpi.c
@@ -88,6 +88,7 @@ struct madt_table_data {
 	device_t dev;
 	ACPI_MADT_GENERIC_DISTRIBUTOR *dist;
 	int count;
+	bool rdist_use_gicc;
 };
 
 static void
@@ -120,12 +121,16 @@ static void
 rdist_map(ACPI_SUBTABLE_HEADER *entry, void *arg)
 {
 	ACPI_MADT_GENERIC_REDISTRIBUTOR *redist;
+	ACPI_MADT_GENERIC_INTERRUPT *intr;
 	struct madt_table_data *madt_data;
+	rman_res_t count;
 
 	madt_data = (struct madt_table_data *)arg;
 
 	switch(entry->Type) {
 	case ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR:
+		if (madt_data->rdist_use_gicc)
+			break;
 		redist = (ACPI_MADT_GENERIC_REDISTRIBUTOR *)entry;
 
 		madt_data->count++;
@@ -134,6 +139,23 @@ rdist_map(ACPI_SUBTABLE_HEADER *entry, void *arg)
 		    redist->Length);
 		break;
 
+	case ACPI_MADT_TYPE_GENERIC_INTERRUPT:
+		if (!madt_data->rdist_use_gicc)
+			break;
+
+		intr = (ACPI_MADT_GENERIC_INTERRUPT *)entry;
+
+		madt_data->count++;
+		/*
+		 * Map the two 64k redistributor frames.
+		 */
+		count = GICR_RD_BASE_SIZE + GICR_SGI_BASE_SIZE;
+		if (madt_data->dist->Version == ACPI_MADT_GIC_VERSION_V4)
+			count += GICR_VLPI_BASE_SIZE + GICR_RESERVED_SIZE;
+		BUS_SET_RESOURCE(madt_data->parent, madt_data->dev,
+		    SYS_RES_MEMORY, madt_data->count, intr->GicrBaseAddress,
+		    count);
+
 	default:
 		break;
 	}
@@ -190,8 +212,18 @@ gic_v3_acpi_identify(driver_t *driver, device_t parent)
 	    madt_data.dist->BaseAddress, 128 * 1024);
 
 	madt_data.dev = dev;
+	madt_data.rdist_use_gicc = false;
 	acpi_walk_subtables(madt + 1, (char *)madt + madt->Header.Length,
 	    rdist_map, &madt_data);
+	if (madt_data.count == 0) {
+		/*
+		 * No redistributors found, fall back to use the GICR
+		 * address from the GICC sub-table.
+		 */
+		madt_data.rdist_use_gicc = true;
+		acpi_walk_subtables(madt + 1, (char *)madt + madt->Header.Length,
+		    rdist_map, &madt_data);
+	}
 
 	acpi_set_private(dev, (void *)(uintptr_t)madt_data.dist->Version);
 
@@ -224,6 +256,15 @@ madt_count_redistrib(ACPI_SUBTABLE_HEADER *entry, void *arg)
 		sc->gic_redists.nregions++;
 }
 
+static void
+madt_count_gicc_redistrib(ACPI_SUBTABLE_HEADER *entry, void *arg)
+{
+	struct gic_v3_softc *sc = arg;
+
+	if (entry->Type == ACPI_MADT_TYPE_GENERIC_INTERRUPT)
+		sc->gic_redists.nregions++;
+}
+
 static int
 gic_v3_acpi_count_regions(device_t dev)
 {
@@ -245,6 +286,12 @@ gic_v3_acpi_count_regions(device_t dev)
 
 	acpi_walk_subtables(madt + 1, (char *)madt + madt->Header.Length,
 	    madt_count_redistrib, sc);
+	/* Fall back to use the distributor GICR base address */
+	if (sc->gic_redists.nregions == 0) {
+		acpi_walk_subtables(madt + 1,
+		    (char *)madt + madt->Header.Length,
+		    madt_count_gicc_redistrib, sc);
+	}
 	acpi_unmap_table(madt);
 
 	return (sc->gic_redists.nregions > 0 ? 0 : ENXIO);