irqchip: gicv3-its: Use non-cacheable accesses when no shareability
If the ITS or the redistributors report their shareability as zero,
then it is important to make sure they will no generate any cacheable
traffic, as this is unlikely to produce the expected result.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1427465705-17126-5-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 56353f6..9687f8a 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -802,6 +802,7 @@
int i;
int psz = SZ_64K;
u64 shr = GITS_BASER_InnerShareable;
+ u64 cache = GITS_BASER_WaWb;
for (i = 0; i < GITS_BASER_NR_REGS; i++) {
u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);
@@ -848,7 +849,7 @@
val = (virt_to_phys(base) |
(type << GITS_BASER_TYPE_SHIFT) |
((entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT) |
- GITS_BASER_WaWb |
+ cache |
shr |
GITS_BASER_VALID);
@@ -874,9 +875,12 @@
* Shareability didn't stick. Just use
* whatever the read reported, which is likely
* to be the only thing this redistributor
- * supports.
+ * supports. If that's zero, make it
+ * non-cacheable as well.
*/
shr = tmp & GITS_BASER_SHAREABILITY_MASK;
+ if (!shr)
+ cache = GITS_BASER_nC;
goto retry_baser;
}
@@ -980,6 +984,17 @@
tmp = readq_relaxed(rbase + GICR_PROPBASER);
if ((tmp ^ val) & GICR_PROPBASER_SHAREABILITY_MASK) {
+ if (!(tmp & GICR_PROPBASER_SHAREABILITY_MASK)) {
+ /*
+ * The HW reports non-shareable, we must
+ * remove the cacheability attributes as
+ * well.
+ */
+ val &= ~(GICR_PROPBASER_SHAREABILITY_MASK |
+ GICR_PROPBASER_CACHEABILITY_MASK);
+ val |= GICR_PROPBASER_nC;
+ writeq_relaxed(val, rbase + GICR_PROPBASER);
+ }
pr_info_once("GIC: using cache flushing for LPI property table\n");
gic_rdists->flags |= RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING;
}
@@ -990,6 +1005,18 @@
GICR_PENDBASER_WaWb);
writeq_relaxed(val, rbase + GICR_PENDBASER);
+ tmp = readq_relaxed(rbase + GICR_PENDBASER);
+
+ if (!(tmp & GICR_PENDBASER_SHAREABILITY_MASK)) {
+ /*
+ * The HW reports non-shareable, we must remove the
+ * cacheability attributes as well.
+ */
+ val &= ~(GICR_PENDBASER_SHAREABILITY_MASK |
+ GICR_PENDBASER_CACHEABILITY_MASK);
+ val |= GICR_PENDBASER_nC;
+ writeq_relaxed(val, rbase + GICR_PENDBASER);
+ }
/* Enable LPIs */
val = readl_relaxed(rbase + GICR_CTLR);
@@ -1422,14 +1449,26 @@
writeq_relaxed(baser, its->base + GITS_CBASER);
tmp = readq_relaxed(its->base + GITS_CBASER);
- writeq_relaxed(0, its->base + GITS_CWRITER);
- writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
if ((tmp ^ baser) & GITS_CBASER_SHAREABILITY_MASK) {
+ if (!(tmp & GITS_CBASER_SHAREABILITY_MASK)) {
+ /*
+ * The HW reports non-shareable, we must
+ * remove the cacheability attributes as
+ * well.
+ */
+ baser &= ~(GITS_CBASER_SHAREABILITY_MASK |
+ GITS_CBASER_CACHEABILITY_MASK);
+ baser |= GITS_CBASER_nC;
+ writeq_relaxed(baser, its->base + GITS_CBASER);
+ }
pr_info("ITS: using cache flushing for cmd queue\n");
its->flags |= ITS_FLAGS_CMDQ_NEEDS_FLUSHING;
}
+ writeq_relaxed(0, its->base + GITS_CWRITER);
+ writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
+
if (of_property_read_bool(its->msi_chip.of_node, "msi-controller")) {
its->domain = irq_domain_add_tree(NULL, &its_domain_ops, its);
if (!its->domain) {