From: Lorenzo Pieralisi lpieralisi@kernel.org
[ Upstream commit 3a0fff0fb6a3861fa05416f21858cf0c75cbf944 ]
The GIC architecture specification defines a set of registers for redistributors and ITSes that control the sharebility and cacheability attributes of redistributors/ITSes initiator ports on the interconnect (GICR_[V]PROPBASER, GICR_[V]PENDBASER, GITS_BASER<n>).
Architecturally the GIC provides a means to drive shareability and cacheability attributes signals and related IWB/OWB/ISH barriers but it is not mandatory for designs to wire up the corresponding interconnect signals that control the cacheability/shareability of transactions.
Redistributors and ITSes interconnect ports can be connected to non-coherent interconnects that are not able to manage the shareability/cacheability attributes; this implicitly makes the redistributors and ITSes non-coherent observers.
So far, the GIC driver on probe executes a write to "probe" for the redistributors and ITSes registers shareability bitfields by writing a value (ie InnerShareable - the shareability domain the CPUs are in) and check it back to detect whether the value sticks or not; this hinges on a GIC programming model behaviour that predates the current specifications, that just define shareability bits as writeable but do not guarantee that writing certain shareability values enable the expected behaviour for the redistributors/ITSes memory interconnect ports.
To enable non-coherent GIC designs, introduce the "dma-noncoherent" device tree property to allow firmware to describe redistributors and ITSes as non-coherent observers on the memory interconnect and use the property to force the shareability attributes to be programmed into the redistributors and ITSes registers through the GIC quirks mechanism.
Signed-off-by: Lorenzo Pieralisi lpieralisi@kernel.org Cc: Robin Murphy robin.murphy@arm.com Cc: Mark Rutland mark.rutland@arm.com Cc: Marc Zyngier maz@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20231006125929.48591-3-lpieralisi@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/irqchip/irq-gic-common.h | 4 ++++ drivers/irqchip/irq-gic-v3-its.c | 21 +++++++++++++++++---- drivers/irqchip/irq-gic-v3.c | 13 +++++++++++++ 3 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h index 3db4592cda1c0..f407cce9ecaaa 100644 --- a/drivers/irqchip/irq-gic-common.h +++ b/drivers/irqchip/irq-gic-common.h @@ -29,4 +29,8 @@ void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks, void gic_enable_of_quirks(const struct device_node *np, const struct gic_quirk *quirks, void *data);
+#define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING (1 << 0) +#define RDIST_FLAGS_RD_TABLES_PREALLOCATED (1 << 1) +#define RDIST_FLAGS_FORCE_NON_SHAREABLE (1 << 2) + #endif /* _IRQ_GIC_COMMON_H */ diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 5e57b605b7c61..75a2dd550625b 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -44,10 +44,6 @@ #define ITS_FLAGS_WORKAROUND_CAVIUM_23144 (1ULL << 2) #define ITS_FLAGS_FORCE_NON_SHAREABLE (1ULL << 3)
-#define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING (1 << 0) -#define RDIST_FLAGS_RD_TABLES_PREALLOCATED (1 << 1) -#define RDIST_FLAGS_FORCE_NON_SHAREABLE (1 << 2) - #define RD_LOCAL_LPI_ENABLED BIT(0) #define RD_LOCAL_PENDTABLE_PREALLOCATED BIT(1) #define RD_LOCAL_MEMRESERVE_DONE BIT(2) @@ -4754,6 +4750,14 @@ static bool __maybe_unused its_enable_rk3588001(void *data) return true; }
+static bool its_set_non_coherent(void *data) +{ + struct its_node *its = data; + + its->flags |= ITS_FLAGS_FORCE_NON_SHAREABLE; + return true; +} + static const struct gic_quirk its_quirks[] = { #ifdef CONFIG_CAVIUM_ERRATUM_22375 { @@ -4808,6 +4812,11 @@ static const struct gic_quirk its_quirks[] = { .init = its_enable_rk3588001, }, #endif + { + .desc = "ITS: non-coherent attribute", + .property = "dma-noncoherent", + .init = its_set_non_coherent, + }, { } }; @@ -4817,6 +4826,10 @@ static void its_enable_quirks(struct its_node *its) u32 iidr = readl_relaxed(its->base + GITS_IIDR);
gic_enable_quirks(iidr, its_quirks, its); + + if (is_of_node(its->fwnode_handle)) + gic_enable_of_quirks(to_of_node(its->fwnode_handle), + its_quirks, its); }
static int its_save_disable(void) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index eedfa8e9f0772..f59ac9586b7b1 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -1857,6 +1857,14 @@ static bool gic_enable_quirk_arm64_2941627(void *data) return true; }
+static bool rd_set_non_coherent(void *data) +{ + struct gic_chip_data *d = data; + + d->rdists.flags |= RDIST_FLAGS_FORCE_NON_SHAREABLE; + return true; +} + static const struct gic_quirk gic_quirks[] = { { .desc = "GICv3: Qualcomm MSM8996 broken firmware", @@ -1923,6 +1931,11 @@ static const struct gic_quirk gic_quirks[] = { .mask = 0xff0f0fff, .init = gic_enable_quirk_arm64_2941627, }, + { + .desc = "GICv3: non-coherent attribute", + .property = "dma-noncoherent", + .init = rd_set_non_coherent, + }, { } };