[PATCH v3 05/59] irqchip/gic-v3-its: Add probing for VLPI properties

Marc Zyngier
2017-07-31T17:25:42Z

Add the probing code for the ITS VLPI support. This includes
configuring the ITS number if not supporting the single VMOVP
command feature.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-gic-v3-its.c | 71 +++++++++++++++++++++++++++++++++++---
include/linux/irqchip/arm-gic-v3.h | 5 +++
2 files changed, 72 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ae6b2cee09fa..e7a7dc9ad585 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -101,6 +101,7 @@ struct its_node {
u32 ite_size;
u32 device_ids;
int numa_node;
+ bool is_v4;
};

#define ITS_ITT_ALIGN SZ_256
@@ -133,6 +134,14 @@ static DEFINE_SPINLOCK(its_lock);
static struct rdists *gic_rdists;
static struct irq_domain *its_parent;

+/*
+ * We have a maximum number of 16 ITSs in the whole system if we're
+ * using the ITSList mechanism
+ */
+#define ITS_LIST_MAX 16
+
+static unsigned long its_list_map;
+
#define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)

@@ -1673,13 +1682,51 @@ static int its_init_domain(struct fwnode_handle *handle, struct its_node *its)
return 0;
}

+static int __init its_compute_its_list_map(struct resource *res,
+ void __iomem *its_base)
+{
+ int its_number;
+ u32 ctlr;
+
+ /*
+ * This is assumed to be done early enough that we're
+ * guaranteed to be single-threaded, hence no
+ * locking. Should this change, we should address
+ * this.
+ */
+ its_number = find_first_zero_bit(&its_list_map, ITS_LIST_MAX);
+ if (its_number >= ITS_LIST_MAX) {
+ pr_err("ITS@%pa: No ITSList entry available!\n",
+ &res->start);
+ return -EINVAL;
+ }
+
+ ctlr = readl_relaxed(its_base + GITS_CTLR);
+ ctlr &= ~GITS_CTLR_ITS_NUMBER;
+ ctlr |= its_number << GITS_CTLR_ITS_NUMBER_SHIFT;
+ writel_relaxed(ctlr, its_base + GITS_CTLR);
+ ctlr = readl_relaxed(its_base + GITS_CTLR);
+ if ((ctlr & GITS_CTLR_ITS_NUMBER) != (its_number << GITS_CTLR_ITS_NUMBER_SHIFT)) {
+ its_number = ctlr & GITS_CTLR_ITS_NUMBER;
+ its_number >>= GITS_CTLR_ITS_NUMBER_SHIFT;
+ }
+
+ if (test_and_set_bit(its_number, &its_list_map)) {
+ pr_err("ITS@%pa: Duplicate ITSList entry %d\n",
+ &res->start, its_number);
+ return -EINVAL;
+ }
+
+ return its_number;
+}
+
static int __init its_probe_one(struct resource *res,
struct fwnode_handle *handle, int numa_node)
{
struct its_node *its;
void __iomem *its_base;
- u32 val;
- u64 baser, tmp;
+ u32 val, ctlr;
+ u64 baser, tmp, typer;
int err;

its_base = ioremap(res->start, resource_size(res));
@@ -1712,9 +1759,24 @@ static int __init its_probe_one(struct resource *res,
raw_spin_lock_init(&its->lock);
INIT_LIST_HEAD(&its->entry);
INIT_LIST_HEAD(&its->its_device_list);
+ typer = gic_read_typer(its_base + GITS_TYPER);
its->base = its_base;
its->phys_base = res->start;
- its->ite_size = ((gic_read_typer(its_base + GITS_TYPER) >> 4) & 0xf) + 1;
+ its->ite_size = GITS_TYPER_ITT_ENTRY_SIZE(typer);
+ its->is_v4 = !!(typer & GITS_TYPER_VLPIS);
+ if (its->is_v4) {
+ if (!(typer & GITS_TYPER_VMOVP)) {
+ err = its_compute_its_list_map(res, its_base);
+ if (err < 0)
+ goto out_free_its;
+
+ pr_info("ITS@%pa: Using ITS number %d\n",
+ &res->start, err);
+ } else {
+ pr_info("ITS@%pa: Single VMOVP capable\n", &res->start);
+ }
+ }
+
its->numa_node = numa_node;

its->cmd_base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
@@ -1761,7 +1823,8 @@ static int __init its_probe_one(struct resource *res,
}

gits_write_cwriter(0, its->base + GITS_CWRITER);
- writel_relaxed(GITS_CTLR_ENABLE, its->base + GITS_CTLR);
+ ctlr = readl_relaxed(its->base + GITS_CTLR);
+ writel_relaxed(ctlr | GITS_CTLR_ENABLE, its->base + GITS_CTLR);

err = its_init_domain(handle, its);
if (err)
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index 20a553423ac7..af8c55105fc2 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -235,15 +235,20 @@
#define GITS_TRANSLATER 0x10040

#define GITS_CTLR_ENABLE (1U << 0)
+#define GITS_CTLR_ITS_NUMBER_SHIFT 4
+#define GITS_CTLR_ITS_NUMBER (0xFU << GITS_CTLR_ITS_NUMBER_SHIFT)
#define GITS_CTLR_QUIESCENT (1U << 31)

#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) & 0x1f) + 1)
#define GITS_TYPER_IDBITS_SHIFT 8
#define GITS_TYPER_DEVBITS_SHIFT 13
#define GITS_TYPER_DEVBITS(r) ((((r) >> GITS_TYPER_DEVBITS_SHIFT) & 0x1f) + 1)
#define GITS_TYPER_PTA (1UL << 19)
#define GITS_TYPER_HWCOLLCNT_SHIFT 24
+#define GITS_TYPER_VMOVP (1ULL << 37)

#define GITS_IIDR_REV_SHIFT 12
#define GITS_IIDR_REV_MASK (0xf << GITS_IIDR_REV_SHIFT)
--
2.11.0