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Subject[PATCH 2/3] irqchip/gic-v3: Detect LPI invalidation MMIO registers
Date
Since GICv4.1, an implementation can offer the same MMIO-based
implementation as DirectLPI, only with an ITS. Given that this
can be hugely beneficial for workloads that are very LPI masking
heavy (although these workloads are admitedly a bit odd).

Interestingly, this is independent of RVPEI, which only *implies*
the functionnality.

So let's detect whether the implementation has GICR_CTLR.IR set,
and propagate this as DirectLPI to the ITS driver.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/irqchip/irq-gic-v3.c | 15 +++++++++++----
include/linux/irqchip/arm-gic-v3.h | 2 ++
2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 736163d36b13..363bfe172033 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -918,7 +918,11 @@ static int gic_populate_rdist(void)
static int __gic_update_rdist_properties(struct redist_region *region,
void __iomem *ptr)
{
- u64 typer = gic_read_typer(ptr + GICR_TYPER);
+ u64 typer;
+ u32 ctlr;
+
+ typer = gic_read_typer(ptr + GICR_TYPER);
+ ctlr = readl_relaxed(ptr + GICR_CTLR);

/* Boot-time cleanip */
if ((typer & GICR_TYPER_VLPIS) && (typer & GICR_TYPER_RVPEID)) {
@@ -941,6 +945,7 @@ static int __gic_update_rdist_properties(struct redist_region *region,
/* RVPEID implies some form of DirectLPI, no matter what the doc says... :-/ */
gic_data.rdists.has_rvpeid &= !!(typer & GICR_TYPER_RVPEID);
gic_data.rdists.has_direct_lpi &= (!!(typer & GICR_TYPER_DirectLPIS) |
+ !!(ctlr & GICR_CTLR_IR) |
gic_data.rdists.has_rvpeid);
gic_data.rdists.has_vpend_valid_dirty &= !!(typer & GICR_TYPER_DIRTY);

@@ -962,7 +967,11 @@ static void gic_update_rdist_properties(void)
gic_iterate_rdists(__gic_update_rdist_properties);
if (WARN_ON(gic_data.ppi_nr == UINT_MAX))
gic_data.ppi_nr = 0;
- pr_info("%d PPIs implemented\n", gic_data.ppi_nr);
+ pr_info("GICv3 features: %d PPIs, %s%s\n",
+ gic_data.ppi_nr,
+ gic_data.has_rss ? "RSS " : "",
+ gic_data.rdists.has_direct_lpi ? "DirectLPI " : "");
+
if (gic_data.rdists.has_vlpis)
pr_info("GICv4 features: %s%s%s\n",
gic_data.rdists.has_direct_lpi ? "DirectLPI " : "",
@@ -1797,8 +1806,6 @@ static int __init gic_init_bases(void __iomem *dist_base,
irq_domain_update_bus_token(gic_data.domain, DOMAIN_BUS_WIRED);

gic_data.has_rss = !!(typer & GICD_TYPER_RSS);
- pr_info("Distributor has %sRange Selector support\n",
- gic_data.has_rss ? "" : "no ");

if (typer & GICD_TYPER_MBIS) {
err = mbi_init(handle, gic_data.domain);
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 12d91f0dedf9..aeb8ced53880 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -127,6 +127,8 @@
#define GICR_PIDR2 GICD_PIDR2

#define GICR_CTLR_ENABLE_LPIS (1UL << 0)
+#define GICR_CTLR_IR (1UL << 1)
+#define GICR_CTLR_CES (1UL << 2)
#define GICR_CTLR_RWP (1UL << 3)

#define GICR_TYPER_CPU_NUMBER(r) (((r) >> 8) & 0xffff)
--
2.34.1
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