irqchip/gic-v3-its: Kill its->ite_size and use TYPER copy instead

Now that we have a copy of TYPER in the ITS structure, rely on this
to provide the same service as its->ite_size, which gets axed.
Errata workarounds are now updating the cached fields instead of
requiring a separate field in the ITS structure.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20191027144234.8395-6-maz@kernel.org
Link: https://lore.kernel.org/r/20191108165805.3071-6-maz@kernel.org

drivers/irqchip/irq-gic-v3-its.c

@@ -6,6 +6,7 @@
 
 #include <linux/acpi.h>
 #include <linux/acpi_iort.h>
+#include <linux/bitfield.h>
 #include <linux/bitmap.h>
 #include <linux/cpu.h>
 #include <linux/crash_dump.h>
@@ -108,7 +109,6 @@ struct its_node {
 	struct list_head	its_device_list;
 	u64			flags;
 	unsigned long		list_nr;
-	u32			ite_size;
 	u32			device_ids;
 	int			numa_node;
 	unsigned int		msi_domain_flags;
@@ -2453,7 +2453,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
 	 * sized as a power of two (and you need at least one bit...).
 	 */
 	nr_ites = max(2, nvecs);
-	sz = nr_ites * its->ite_size;
+	sz = nr_ites * (FIELD_GET(GITS_TYPER_ITT_ENTRY_SIZE, its->typer) + 1);
 	sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
 	itt = kzalloc_node(sz, GFP_KERNEL, its->numa_node);
 	if (alloc_lpis) {
@@ -3268,7 +3268,8 @@ static bool __maybe_unused its_enable_quirk_qdf2400_e0065(void *data)
 	struct its_node *its = data;
 
 	/* On QDF2400, the size of the ITE is 16Bytes */
-	its->ite_size = 16;
+	its->typer &= ~GITS_TYPER_ITT_ENTRY_SIZE;
+	its->typer |= FIELD_PREP(GITS_TYPER_ITT_ENTRY_SIZE, 16 - 1);
 
 	return true;
 }
@@ -3637,7 +3638,6 @@ static int __init its_probe_one(struct resource *res,
 	its->typer = typer;
 	its->base = its_base;
 	its->phys_base = res->start;
-	its->ite_size = GITS_TYPER_ITT_ENTRY_SIZE(typer);
 	its->device_ids = GITS_TYPER_DEVBITS(typer);
 	if (is_v4(its)) {
 		if (!(typer & GITS_TYPER_VMOVP)) {

include/linux/irqchip/arm-gic-v3.h

@@ -334,7 +334,7 @@
 #define GITS_TYPER_PLPIS		(1UL << 0)
 #define GITS_TYPER_VLPIS		(1UL << 1)
 #define GITS_TYPER_ITT_ENTRY_SIZE_SHIFT	4
-#define GITS_TYPER_ITT_ENTRY_SIZE(r)	((((r) >> GITS_TYPER_ITT_ENTRY_SIZE_SHIFT) & 0xf) + 1)
+#define GITS_TYPER_ITT_ENTRY_SIZE	GENMASK_ULL(7, 4)
 #define GITS_TYPER_IDBITS_SHIFT		8
 #define GITS_TYPER_DEVBITS_SHIFT	13
 #define GITS_TYPER_DEVBITS(r)		((((r) >> GITS_TYPER_DEVBITS_SHIFT) & 0x1f) + 1)