Re: [PATCH v2 09/36] irqchip/gic-v3: Add GICv4.1 VPEID size discovery

From: Zenghui Yu
Date: Thu Oct 31 2019 - 08:02:38 EST


Hi Marc,

On 2019/10/27 22:42, Marc Zyngier wrote:
While GICv4.0 mandates 16 bit worth of VPEIDs, GICv4.1 allows smaller
implementations to be built. Add the required glue to dynamically
compute the limit.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 11 ++++++++++-
drivers/irqchip/irq-gic-v3.c | 3 +++
include/linux/irqchip/arm-gic-v3.h | 5 +++++
3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 94c9c2e9f917..40912b3fb0e1 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -121,7 +121,16 @@ struct its_node {
#define ITS_ITT_ALIGN SZ_256
/* The maximum number of VPEID bits supported by VLPI commands */
-#define ITS_MAX_VPEID_BITS (16)
+#define ITS_MAX_VPEID_BITS \
+ ({ \
+ int nvpeid = 16; \
+ if (gic_rdists->has_rvpeid && \
+ gic_rdists->gicd_typer2 & GICD_TYPER2_VIL) \
+ nvpeid = 1 + (gic_rdists->gicd_typer2 & \
+ GICD_TYPER2_VID); \

Does it make sense to let nvpeid not more than 16 here? As the spec says
"Values above 0x0F are RESERVED". But I don't know why should we have
this restriction ;-)

Either way,

Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>


Thanks

+ \
+ nvpeid; \
+ })
#define ITS_MAX_VPEID (1 << (ITS_MAX_VPEID_BITS))
/* Convert page order to size in bytes */
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 4f20caf9bc88..50538709bd49 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1556,6 +1556,9 @@ static int __init gic_init_bases(void __iomem *dist_base,
pr_info("%d SPIs implemented\n", GIC_LINE_NR - 32);
pr_info("%d Extended SPIs implemented\n", GIC_ESPI_NR);
+
+ gic_data.rdists.gicd_typer2 = readl_relaxed(gic_data.dist_base + GICD_TYPER2);
+
gic_data.domain = irq_domain_create_tree(handle, &gic_irq_domain_ops,
&gic_data);
irq_domain_update_bus_token(gic_data.domain, DOMAIN_BUS_WIRED);
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index c98f34296599..8c6be56da7e9 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -13,6 +13,7 @@
#define GICD_CTLR 0x0000
#define GICD_TYPER 0x0004
#define GICD_IIDR 0x0008
+#define GICD_TYPER2 0x000C
#define GICD_STATUSR 0x0010
#define GICD_SETSPI_NSR 0x0040
#define GICD_CLRSPI_NSR 0x0048
@@ -89,6 +90,9 @@
#define GICD_TYPER_ESPIS(typer) \
(((typer) & GICD_TYPER_ESPI) ? GICD_TYPER_SPIS((typer) >> 27) : 0)
+#define GICD_TYPER2_VIL (1U << 7)
+#define GICD_TYPER2_VID GENMASK(4, 0)
+
#define GICD_IROUTER_SPI_MODE_ONE (0U << 31)
#define GICD_IROUTER_SPI_MODE_ANY (1U << 31)
@@ -613,6 +617,7 @@ struct rdists {
void *prop_table_va;
u64 flags;
u32 gicd_typer;
+ u32 gicd_typer2;
bool has_vlpis;
bool has_rvpeid;
bool has_direct_lpi;