[PATCH v2] irqchip/gic-v3: workaround for ASR8601 when reading mpidr

[zhengyan]

This patch add workaround for ASR8601, which uses an armv8.2
processor with a gic-500. But gic-500 is incompatible with
ARMv8.2 implementations from ARM.

ARMv8.2 from ARM implementation uses Multiprocessor Affinity
Register to identify the logical address of the core by
| cluster | core | thread |.
However, gic-500 only supports topologies with
affinity levels less than 2 as
| cluster | core|.

So we need this patch as workaround to shift the MPIDR values
to ensure proper functionality

Signed-off-by: zhengyan <zhengyan@xxxxxxxxxxxx>
---
 Documentation/arm64/silicon-errata.rst |  4 ++++
 drivers/irqchip/irq-gic-v3.c           | 30 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst
index 9e311bc43e05..d6430ade349d 100644
--- a/Documentation/arm64/silicon-errata.rst
+++ b/Documentation/arm64/silicon-errata.rst
@@ -214,3 +214,7 @@ stable kernels.
 +----------------+-----------------+-----------------+-----------------------------+
 | Fujitsu        | A64FX           | E#010001        | FUJITSU_ERRATUM_010001      |
 +----------------+-----------------+-----------------+-----------------------------+
+
++----------------+-----------------+-----------------+-----------------------------+
+| ASR            | ASR8601         | #8601001        | N/A                         |
++----------------+-----------------+-----------------+-----------------------------+
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 6fcee221f201..cf64783dfe70 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -39,6 +39,9 @@
 
 #define FLAGS_WORKAROUND_GICR_WAKER_MSM8996	(1ULL << 0)
 #define FLAGS_WORKAROUND_CAVIUM_ERRATUM_38539	(1ULL << 1)
+#define FLAGS_WORKAROUND_ASR_ERRATUM_8601001	(1ULL << 2)
+
+#define ASR8601_AFF_QUIRK(aff)			(aff >> 8)
 
 #define GIC_IRQ_TYPE_PARTITION	(GIC_IRQ_TYPE_LPI + 1)
 
@@ -659,6 +662,9 @@ static u64 gic_mpidr_to_affinity(unsigned long mpidr)
 {
 	u64 aff;
 
+	if (gic_data.flags & FLAGS_WORKAROUND_ASR_ERRATUM_8601001)
+		mpidr = ASR8601_AFF_QUIRK(mpidr);
+
 	aff = ((u64)MPIDR_AFFINITY_LEVEL(mpidr, 3) << 32 |
 	       MPIDR_AFFINITY_LEVEL(mpidr, 2) << 16 |
 	       MPIDR_AFFINITY_LEVEL(mpidr, 1) << 8  |
@@ -970,6 +976,9 @@ static int __gic_populate_rdist(struct redist_region *region, void __iomem *ptr)
 	 * Convert affinity to a 32bit value that can be matched to
 	 * GICR_TYPER bits [63:32].
 	 */
+	if (gic_data.flags & FLAGS_WORKAROUND_ASR_ERRATUM_8601001)
+		mpidr = ASR8601_AFF_QUIRK(mpidr);
+
 	aff = (MPIDR_AFFINITY_LEVEL(mpidr, 3) << 24 |
 	       MPIDR_AFFINITY_LEVEL(mpidr, 2) << 16 |
 	       MPIDR_AFFINITY_LEVEL(mpidr, 1) << 8 |
@@ -1265,6 +1274,9 @@ static u16 gic_compute_target_list(int *base_cpu, const struct cpumask *mask,
 	unsigned long mpidr = cpu_logical_map(cpu);
 	u16 tlist = 0;
 
+	if (gic_data.flags & FLAGS_WORKAROUND_ASR_ERRATUM_8601001)
+		mpidr = ASR8601_AFF_QUIRK(mpidr);
+
 	while (cpu < nr_cpu_ids) {
 		tlist |= 1 << (mpidr & 0xf);
 
@@ -1275,6 +1287,8 @@ static u16 gic_compute_target_list(int *base_cpu, const struct cpumask *mask,
 
 		mpidr = cpu_logical_map(cpu);
 
+		if (gic_data.flags & FLAGS_WORKAROUND_ASR_ERRATUM_8601001)
+			mpidr = ASR8601_AFF_QUIRK(mpidr);
 		if (cluster_id != MPIDR_TO_SGI_CLUSTER_ID(mpidr)) {
 			cpu--;
 			goto out;
@@ -1321,6 +1335,8 @@ static void gic_ipi_send_mask(struct irq_data *d, const struct cpumask *mask)
 		u64 cluster_id = MPIDR_TO_SGI_CLUSTER_ID(cpu_logical_map(cpu));
 		u16 tlist;
 
+		if (gic_data.flags & FLAGS_WORKAROUND_ASR_ERRATUM_8601001)
+			cluster_id = MPIDR_TO_SGI_CLUSTER_ID(ASR8601_AFF_QUIRK(cpu_logical_map(cpu)));
 		tlist = gic_compute_target_list(&cpu, mask, cluster_id);
 		gic_send_sgi(cluster_id, tlist, d->hwirq);
 	}
@@ -1786,6 +1802,15 @@ static bool gic_enable_quirk_nvidia_t241(void *data)
 	return true;
 }
 
+static bool gic_enable_quirk_asr8601(void *data)
+{
+	struct gic_chip_data *d = data;
+
+	d->flags |= FLAGS_WORKAROUND_ASR_ERRATUM_8601001;
+
+	return true;
+}
+
 static const struct gic_quirk gic_quirks[] = {
 	{
 		.desc	= "GICv3: Qualcomm MSM8996 broken firmware",
@@ -1823,6 +1848,11 @@ static const struct gic_quirk gic_quirks[] = {
 		.mask	= 0xffffffff,
 		.init	= gic_enable_quirk_nvidia_t241,
 	},
+	{
+		.desc	= "GICv3: ASR erratum 8601001",
+		.compatible = "asr,asr8601-gic-v3",
+		.init	= gic_enable_quirk_asr8601,
+	},
 	{
 	}
 };
-- 
2.25.1