[PATCH 1/7] irqchip/gic-v3: Add a DMA Non-Coherent flag

[Lucas Tanure]

The GIC600 integration in RK356x, used in rk3588, doesn't support
any of the shareability or cacheability attributes, and requires
both values to be set to 0b00 for all the ITS and Redistributor
tables.

This is loosely based on prior work from XiaoDong Huang and
Peter Geis fixing this issue specifically for Rockchip 356x.

Suggested-by: Robin Murphy <robin.murphy at arm.com>
Signed-off-by: Lucas Tanure <lucas.tanure at collabora.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 973ede0197e3..1c334dfeb647 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -42,6 +42,7 @@
 #define ITS_FLAGS_CMDQ_NEEDS_FLUSHING		(1ULL << 0)
 #define ITS_FLAGS_WORKAROUND_CAVIUM_22375	(1ULL << 1)
 #define ITS_FLAGS_WORKAROUND_CAVIUM_23144	(1ULL << 2)
+#define ITS_FLAGS_DMA_NON_COHERENT		(1ULL << 3)
 
 #define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING	(1 << 0)
 #define RDIST_FLAGS_RD_TABLES_PREALLOCATED	(1 << 1)
@@ -2359,6 +2360,13 @@ static int its_setup_baser(struct its_node *its, struct its_baser *baser,
 	its_write_baser(its, baser, val);
 	tmp = baser->val;
 
+	if (its->flags & ITS_FLAGS_DMA_NON_COHERENT) {
+		if (tmp & GITS_BASER_SHAREABILITY_MASK)
+			tmp &= ~GITS_BASER_SHAREABILITY_MASK;
+		else
+			gic_flush_dcache_to_poc(base, PAGE_ORDER_TO_SIZE(order));
+	}
+
 	if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
 		/*
 		 * Shareability didn't stick. Just use
@@ -3055,6 +3063,7 @@ static u64 its_clear_vpend_valid(void __iomem *vlpi_base, u64 clr, u64 set)
 
 static void its_cpu_init_lpis(void)
 {
+	struct its_node *its = list_first_entry(&its_nodes, struct its_node, entry);
 	void __iomem *rbase = gic_data_rdist_rd_base();
 	struct page *pend_page;
 	phys_addr_t paddr;
@@ -3096,6 +3105,9 @@ static void its_cpu_init_lpis(void)
 	gicr_write_propbaser(val, rbase + GICR_PROPBASER);
 	tmp = gicr_read_propbaser(rbase + GICR_PROPBASER);
 
+	if (its->flags & ITS_FLAGS_DMA_NON_COHERENT)
+		tmp &= ~GICR_PROPBASER_SHAREABILITY_MASK;
+
 	if ((tmp ^ val) & GICR_PROPBASER_SHAREABILITY_MASK) {
 		if (!(tmp & GICR_PROPBASER_SHAREABILITY_MASK)) {
 			/*
@@ -3120,6 +3132,9 @@ static void its_cpu_init_lpis(void)
 	gicr_write_pendbaser(val, rbase + GICR_PENDBASER);
 	tmp = gicr_read_pendbaser(rbase + GICR_PENDBASER);
 
+	if (its->flags & ITS_FLAGS_DMA_NON_COHERENT)
+		tmp &= ~GICR_PENDBASER_SHAREABILITY_MASK;
+
 	if (!(tmp & GICR_PENDBASER_SHAREABILITY_MASK)) {
 		/*
 		 * The HW reports non-shareable, we must remove the
@@ -5005,6 +5020,7 @@ static int __init its_compute_its_list_map(struct resource *res,
 static int __init its_probe_one(struct resource *res,
 				struct fwnode_handle *handle, int numa_node)
 {
+	struct device_node *np = to_of_node(handle);
 	struct its_node *its;
 	void __iomem *its_base;
 	u64 baser, tmp, typer;
@@ -5076,6 +5092,9 @@ static int __init its_probe_one(struct resource *res,
 	its->get_msi_base = its_irq_get_msi_base;
 	its->msi_domain_flags = IRQ_DOMAIN_FLAG_MSI_REMAP;
 
+	if (np && !of_dma_is_coherent(np))
+		its->flags |= ITS_FLAGS_DMA_NON_COHERENT;
+
 	its_enable_quirks(its);
 
 	err = its_alloc_tables(its);
@@ -5095,6 +5114,9 @@ static int __init its_probe_one(struct resource *res,
 	gits_write_cbaser(baser, its->base + GITS_CBASER);
 	tmp = gits_read_cbaser(its->base + GITS_CBASER);
 
+	if (its->flags & ITS_FLAGS_DMA_NON_COHERENT)
+		tmp &= ~GITS_CBASER_SHAREABILITY_MASK;
+
 	if ((tmp ^ baser) & GITS_CBASER_SHAREABILITY_MASK) {
 		if (!(tmp & GITS_CBASER_SHAREABILITY_MASK)) {
 			/*
-- 
2.39.2