[PATCH v4 07/10] irqchip / GICv3 / ACPI: Add GICR support via GICC structures

[Hanjun Guo]

On systems supporting GICv3 and above, in MADT GICC structures, the
field of GICR Base Address holds the 64-bit physical address of the
associated Redistributor if the GIC Redistributors are not in the
always-on power domain, so instead of init GICR regions via GIC
redistributor structure(s), init it with GICR base address in GICC
structures in that case.

As GICR base in MADT GICC is another way to indicate the GIC version
is 3 or 4, add its support to find out the GIC versions.

Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
 drivers/irqchip/irq-gic-acpi.c       |  35 ++++++-
 drivers/irqchip/irq-gic-v3.c         | 197 +++++++++++++++++++++++++++++++----
 include/linux/irqchip/arm-gic-acpi.h |   2 +
 3 files changed, 215 insertions(+), 19 deletions(-)

diff --git a/drivers/irqchip/irq-gic-acpi.c b/drivers/irqchip/irq-gic-acpi.c
index 95454e3..3e5c8f4 100644
--- a/drivers/irqchip/irq-gic-acpi.c
+++ b/drivers/irqchip/irq-gic-acpi.c
@@ -21,6 +21,11 @@ static u8 gic_version __initdata = ACPI_MADT_GIC_VERSION_NONE;
 
 static phys_addr_t dist_phy_base __initdata;
 
+u8 __init acpi_gic_version(void)
+{
+	return gic_version;
+}
+
 static int __init
 acpi_gic_parse_distributor(struct acpi_subtable_header *header,
 			   const unsigned long end)
@@ -38,6 +43,27 @@ acpi_gic_parse_distributor(struct acpi_subtable_header *header,
 }
 
 static int __init
+gic_acpi_parse_madt_gicc(struct acpi_subtable_header *header,
+			 const unsigned long end)
+{
+	struct acpi_madt_generic_interrupt *gicc;
+
+	gicc = (struct acpi_madt_generic_interrupt *)header;
+
+	if (BAD_MADT_GICC_ENTRY(gicc, end))
+		return -EINVAL;
+
+	/*
+	 * If GICC is enabled but has no valid gicr base address, then it
+	 * means GICR base is not presented via GICC
+	 */
+	if ((gicc->flags & ACPI_MADT_ENABLED) && !gicc->gicr_base_address)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int __init
 match_gic_redist(struct acpi_subtable_header *header, const unsigned long end)
 {
 	return 0;
@@ -51,7 +77,14 @@ static bool __init acpi_gic_redist_is_present(void)
 	count  =  acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR,
 					match_gic_redist, 0);
 
-	/* that's true if we have at least one GIC redistributor entry */
+	/* has at least one GIC redistributor entry */
+	if (count > 0)
+		return true;
+
+	/* else try to find GICR base in GICC entries */
+	count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
+				      gic_acpi_parse_madt_gicc, 0);
+
 	return count > 0;
 }
 
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index ebc5604..b72ccbb 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -389,9 +389,8 @@ static void __init gic_dist_init(void)
 		writeq_relaxed(affinity, base + GICD_IROUTER + i * 8);
 }
 
-static int gic_populate_rdist(void)
+static int gic_populate_rdist_with_regions(u64 mpidr)
 {
-	u64 mpidr = cpu_logical_map(smp_processor_id());
 	u64 typer;
 	u32 aff;
 	int i;
@@ -439,6 +438,34 @@ static int gic_populate_rdist(void)
 		} while (!(typer & GICR_TYPER_LAST));
 	}
 
+	return -ENODEV;
+}
+
+#ifdef CONFIG_ACPI
+/*
+ * Populate redist when GIC redistributor address is presented in ACPI
+ * MADT GICC entries
+ */
+static int gic_populate_rdist_with_gicr_base(u64 mpidr);
+#else
+static inline int gic_populate_rdist_with_gicr_base(u64 mpidr)
+{
+	return -ENODEV;
+}
+#endif
+
+static int gic_populate_rdist(void)
+{
+	u64 mpidr = cpu_logical_map(smp_processor_id());
+
+	if (gic_data.nr_redist_regions) {
+		if (!gic_populate_rdist_with_regions(mpidr))
+			return 0;
+	} else {
+		if (!gic_populate_rdist_with_gicr_base(mpidr))
+			return 0;
+	}
+
 	/* We couldn't even deal with ourselves... */
 	WARN(true, "CPU%d: mpidr %llx has no re-distributor!\n",
 	     smp_processor_id(), (unsigned long long)mpidr);
@@ -900,6 +927,16 @@ IRQCHIP_DECLARE(gic_v3, "arm,gic-v3", gic_of_init);
 #endif
 
 #ifdef CONFIG_ACPI
+
+struct acpi_gicc_redist {
+	struct list_head list;
+	u64 mpidr;
+	phys_addr_t phys_base;
+	void __iomem *redist_base;
+};
+
+static LIST_HEAD(redist_list);
+
 static struct redist_region *redist_regs __initdata;
 static u32 nr_redist_regions __initdata;
 static phys_addr_t dist_phys_base __initdata;
@@ -932,6 +969,17 @@ gic_acpi_register_redist(u64 phys_base, u64 size)
 	return 0;
 }
 
+static void __init
+gic_acpi_release_redist_regions(void)
+{
+	int i;
+
+	for (i = 0; i < nr_redist_regions; i++)
+		if (redist_regs[i].redist_base)
+			iounmap(redist_regs[i].redist_base);
+	kfree(redist_regs);
+}
+
 static int __init
 gic_acpi_parse_madt_redist(struct acpi_subtable_header *header,
 			const unsigned long end)
@@ -989,9 +1037,130 @@ static int gic_acpi_gsi_desc_populate(struct acpi_gsi_descriptor *data,
 }
 
 static int __init
+gic_acpi_add_gicc_redist(phys_addr_t phys_base, u64 mpidr)
+{
+	struct acpi_gicc_redist *redist;
+
+	redist = kzalloc(sizeof(*redist), GFP_KERNEL);
+	if (!redist)
+		return -ENOMEM;
+
+	redist->mpidr = mpidr;
+	redist->phys_base = phys_base;
+
+	if (acpi_gic_version() == ACPI_MADT_GIC_VERSION_V3)
+		/* RD_base + SGI_base */
+		redist->redist_base = ioremap(phys_base, 2 * SZ_64K);
+	else
+		/*
+		 * RD_base + SGI_base + VLPI_base,
+		 * we don't map reserved page as it's buggy to access it
+		 */
+		redist->redist_base = ioremap(phys_base, 3 * SZ_64K);
+
+	if (!redist->redist_base) {
+		kfree(redist);
+		return -ENOMEM;
+	}
+
+	list_add(&redist->list, &redist_list);
+	return 0;
+}
+
+static void __init
+gic_acpi_release_gicc_redist(void)
+{
+	struct acpi_gicc_redist *redist, *t;
+
+	list_for_each_entry_safe(redist, t, &redist_list, list) {
+		list_del(&redist->list);
+		iounmap(redist->redist_base);
+		kfree(redist);
+	}
+}
+
+static int __init
+gic_acpi_parse_madt_gicc(struct acpi_subtable_header *header,
+			 const unsigned long end)
+{
+	struct acpi_madt_generic_interrupt *gicc;
+
+	gicc = (struct acpi_madt_generic_interrupt *)header;
+
+	if (BAD_MADT_GICC_ENTRY(gicc, end))
+		return -EINVAL;
+
+	/*
+	 * just quietly ingore the disabled CPU(s) and continue
+	 * to find the enabled one(s), if we return error here,
+	 * the scanning will be stopped.
+	 */
+	if (!(gicc->flags & ACPI_MADT_ENABLED))
+		return 0;
+
+	return gic_acpi_add_gicc_redist(gicc->gicr_base_address,
+					gicc->arm_mpidr);
+}
+
+static int gic_populate_rdist_with_gicr_base(u64 mpidr)
+{
+	struct acpi_gicc_redist *redist;
+	void __iomem *ptr;
+	u32 reg;
+
+	list_for_each_entry(redist, &redist_list, list) {
+		if (redist->mpidr != mpidr)
+			continue;
+
+		ptr = redist->redist_base;
+		reg = readl_relaxed(ptr + GICR_PIDR2) & GIC_PIDR2_ARCH_MASK;
+		if (reg != GIC_PIDR2_ARCH_GICv3 && reg != GIC_PIDR2_ARCH_GICv4) {
+			pr_warn("No redistributor present @%p\n", ptr);
+			return -ENODEV;
+		}
+
+		gic_data_rdist_rd_base() = ptr;
+		gic_data_rdist()->phys_base = redist->phys_base;
+		pr_info("CPU%d: found redistributor %llx phys base:%pa\n",
+			smp_processor_id(),
+			(unsigned long long)mpidr,
+			&gic_data_rdist()->phys_base);
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static int __init collect_gicr_base(struct acpi_table_header *table)
+{
+	int count;
+
+	/* Collect redistributor base addresses in GICR entries */
+	count = acpi_parse_entries(ACPI_SIG_MADT,
+			sizeof(struct acpi_table_madt),
+			gic_acpi_parse_madt_redist, table,
+			ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR, 0);
+	if (count > 0)
+		return 0;
+
+	pr_info("No valid GICR entries exist, try GICC entries\n");
+
+	/* Collect redistributor base addresses in GICC entries */
+	count = acpi_parse_entries(ACPI_SIG_MADT,
+			sizeof(struct acpi_table_madt),
+			gic_acpi_parse_madt_gicc, table,
+			ACPI_MADT_TYPE_GENERIC_INTERRUPT, 0);
+	if (count > 0 && !list_empty(&redist_list))
+		return 0;
+
+	pr_info("No valid GICC entries exist for GICR base\n");
+	return -ENODEV;
+}
+
+static int __init
 gic_acpi_init(struct acpi_table_header *table)
 {
-	int count, i, err = 0;
+	int count, err = 0;
 	void __iomem *dist_base;
 
 	/* Get distributor base address */
@@ -1020,30 +1189,22 @@ gic_acpi_init(struct acpi_table_header *table)
 	}
 
 	/* Collect redistributor base addresses */
-	count = acpi_parse_entries(ACPI_SIG_MADT,
-			sizeof(struct acpi_table_madt),
-			gic_acpi_parse_madt_redist, table,
-			ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR, 0);
-	if (count <= 0) {
-		pr_info("No valid GICR entries exist\n");
-		err = -EINVAL;
-		goto out_redist_unmap;
-	}
+	if (collect_gicr_base(table))
+		goto out_release_redist;
 
 	err = gic_init_bases(dist_base, redist_regs, nr_redist_regions, 0,
 			     (void *)ACPI_IRQ_MODEL_GIC);
 	if (err)
-		goto out_redist_unmap;
+		goto out_release_redist;
 
 	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, ACPI_IRQ_MODEL_GIC,
 			   gic_acpi_gsi_desc_populate);
 	return 0;
 
-out_redist_unmap:
-	for (i = 0; i < nr_redist_regions; i++)
-		if (redist_regs[i].redist_base)
-			iounmap(redist_regs[i].redist_base);
-	kfree(redist_regs);
+out_release_redist:
+	gic_acpi_release_redist_regions();
+	if (!list_empty(&redist_list))
+		gic_acpi_release_gicc_redist();
 out_dist_unmap:
 	iounmap(dist_base);
 	return err;
diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h
index 56cd82c..0d43f515 100644
--- a/include/linux/irqchip/arm-gic-acpi.h
+++ b/include/linux/irqchip/arm-gic-acpi.h
@@ -21,5 +21,7 @@
 #define ACPI_GIC_CPU_IF_MEM_SIZE	(SZ_8K)
 #define ACPI_GICV3_DIST_MEM_SIZE	(SZ_64K)
 
+u8 acpi_gic_version(void);
+
 #endif /* CONFIG_ACPI */
 #endif /* ARM_GIC_ACPI_H_ */
-- 
1.9.1

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