[PATCH v3 07/13] irqchip: GICv3: ITS: tables allocators

From: Marc Zyngier
Date: Mon Nov 24 2014 - 09:40:48 EST


The interrupt translation is driven by a set of tables (device,
ITT, and collection) to be in the end delivered to a CPU. Also,
the redistributors rely on a couple of tables (configuration, and
pending) to deliver the interrupts to the CPUs.

This patch adds the required allocators for these tables.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 292 +++++++++++++++++++++++++++++++++++++++
1 file changed, 292 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 4154a16..03f9831 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -91,6 +91,14 @@ struct its_device {
u32 device_id;
};

+static LIST_HEAD(its_nodes);
+static DEFINE_SPINLOCK(its_lock);
+static struct device_node *gic_root_node;
+static struct rdists *gic_rdists;
+
+#define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
+#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
+
/*
* ITS command descriptors - parameters to be encoded in a command
* block.
@@ -689,3 +697,287 @@ static void its_lpi_free(unsigned long *bitmap, int base, int nr_ids)

kfree(bitmap);
}
+
+/*
+ * We allocate 64kB for PROPBASE. That gives us at most 64K LPIs to
+ * deal with (one configuration byte per interrupt). PENDBASE has to
+ * be 64kB aligned (one bit per LPI, plus 8192 bits for SPI/PPI/SGI).
+ */
+#define LPI_PROPBASE_SZ SZ_64K
+#define LPI_PENDBASE_SZ (LPI_PROPBASE_SZ / 8 + SZ_1K)
+
+/*
+ * This is how many bits of ID we need, including the useless ones.
+ */
+#define LPI_NRBITS ilog2(LPI_PROPBASE_SZ + SZ_8K)
+
+#define LPI_PROP_DEFAULT_PRIO 0xa0
+
+static int __init its_alloc_lpi_tables(void)
+{
+ phys_addr_t paddr;
+
+ gic_rdists->prop_page = alloc_pages(GFP_NOWAIT,
+ get_order(LPI_PROPBASE_SZ));
+ if (!gic_rdists->prop_page) {
+ pr_err("Failed to allocate PROPBASE\n");
+ return -ENOMEM;
+ }
+
+ paddr = page_to_phys(gic_rdists->prop_page);
+ pr_info("GIC: using LPI property table @%pa\n", &paddr);
+
+ /* Priority 0xa0, Group-1, disabled */
+ memset(page_address(gic_rdists->prop_page),
+ LPI_PROP_DEFAULT_PRIO | LPI_PROP_GROUP1,
+ LPI_PROPBASE_SZ);
+
+ /* Make sure the GIC will observe the written configuration */
+ __flush_dcache_area(page_address(gic_rdists->prop_page), LPI_PROPBASE_SZ);
+
+ return 0;
+}
+
+static const char *its_base_type_string[] = {
+ [GITS_BASER_TYPE_DEVICE] = "Devices",
+ [GITS_BASER_TYPE_VCPU] = "Virtual CPUs",
+ [GITS_BASER_TYPE_CPU] = "Physical CPUs",
+ [GITS_BASER_TYPE_COLLECTION] = "Interrupt Collections",
+ [GITS_BASER_TYPE_RESERVED5] = "Reserved (5)",
+ [GITS_BASER_TYPE_RESERVED6] = "Reserved (6)",
+ [GITS_BASER_TYPE_RESERVED7] = "Reserved (7)",
+};
+
+static void its_free_tables(struct its_node *its)
+{
+ int i;
+
+ for (i = 0; i < GITS_BASER_NR_REGS; i++) {
+ if (its->tables[i]) {
+ free_page((unsigned long)its->tables[i]);
+ its->tables[i] = NULL;
+ }
+ }
+}
+
+static int its_alloc_tables(struct its_node *its)
+{
+ int err;
+ int i;
+ int psz = PAGE_SIZE;
+ u64 shr = GITS_BASER_InnerShareable;
+
+ for (i = 0; i < GITS_BASER_NR_REGS; i++) {
+ u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);
+ u64 type = GITS_BASER_TYPE(val);
+ u64 entry_size = GITS_BASER_ENTRY_SIZE(val);
+ u64 tmp;
+ void *base;
+
+ if (type == GITS_BASER_TYPE_NONE)
+ continue;
+
+ /* We're lazy and only allocate a single page for now */
+ base = (void *)get_zeroed_page(GFP_KERNEL);
+ if (!base) {
+ err = -ENOMEM;
+ goto out_free;
+ }
+
+ its->tables[i] = base;
+
+retry_baser:
+ val = (virt_to_phys(base) |
+ (type << GITS_BASER_TYPE_SHIFT) |
+ ((entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT) |
+ GITS_BASER_WaWb |
+ shr |
+ GITS_BASER_VALID);
+
+ switch (psz) {
+ case SZ_4K:
+ val |= GITS_BASER_PAGE_SIZE_4K;
+ break;
+ case SZ_16K:
+ val |= GITS_BASER_PAGE_SIZE_16K;
+ break;
+ case SZ_64K:
+ val |= GITS_BASER_PAGE_SIZE_64K;
+ break;
+ }
+
+ val |= (PAGE_SIZE / psz) - 1;
+
+ writeq_relaxed(val, its->base + GITS_BASER + i * 8);
+ tmp = readq_relaxed(its->base + GITS_BASER + i * 8);
+
+ if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
+ /*
+ * Shareability didn't stick. Just use
+ * whatever the read reported, which is likely
+ * to be the only thing this redistributor
+ * supports.
+ */
+ shr = tmp & GITS_BASER_SHAREABILITY_MASK;
+ goto retry_baser;
+ }
+
+ if ((val ^ tmp) & GITS_BASER_PAGE_SIZE_MASK) {
+ /*
+ * Page size didn't stick. Let's try a smaller
+ * size and retry. If we reach 4K, then
+ * something is horribly wrong...
+ */
+ switch (psz) {
+ case SZ_16K:
+ psz = SZ_4K;
+ goto retry_baser;
+ case SZ_64K:
+ psz = SZ_16K;
+ goto retry_baser;
+ }
+ }
+
+ if (val != tmp) {
+ pr_err("ITS: %s: GITS_BASER%d doesn't stick: %lx %lx\n",
+ its->msi_chip.of_node->full_name, i,
+ (unsigned long) val, (unsigned long) tmp);
+ err = -ENXIO;
+ goto out_free;
+ }
+
+ pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n",
+ (int)(PAGE_SIZE / entry_size),
+ its_base_type_string[type],
+ (unsigned long)virt_to_phys(base),
+ psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);
+ }
+
+ return 0;
+
+out_free:
+ its_free_tables(its);
+
+ return err;
+}
+
+static int its_alloc_collections(struct its_node *its)
+{
+ its->collections = kzalloc(nr_cpu_ids * sizeof(*its->collections),
+ GFP_KERNEL);
+ if (!its->collections)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void its_cpu_init_lpis(void)
+{
+ void __iomem *rbase = gic_data_rdist_rd_base();
+ struct page *pend_page;
+ u64 val, tmp;
+
+ /* If we didn't allocate the pending table yet, do it now */
+ pend_page = gic_data_rdist()->pend_page;
+ if (!pend_page) {
+ phys_addr_t paddr;
+ /*
+ * The pending pages have to be at least 64kB aligned,
+ * hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below.
+ */
+ pend_page = alloc_pages(GFP_NOWAIT | __GFP_ZERO,
+ get_order(max(LPI_PENDBASE_SZ, SZ_64K)));
+ if (!pend_page) {
+ pr_err("Failed to allocate PENDBASE for CPU%d\n",
+ smp_processor_id());
+ return;
+ }
+
+ /* Make sure the GIC will observe the zero-ed page */
+ __flush_dcache_area(page_address(pend_page), LPI_PENDBASE_SZ);
+
+ paddr = page_to_phys(pend_page);
+ pr_info("CPU%d: using LPI pending table @%pa\n",
+ smp_processor_id(), &paddr);
+ gic_data_rdist()->pend_page = pend_page;
+ }
+
+ /* Disable LPIs */
+ val = readl_relaxed(rbase + GICR_CTLR);
+ val &= ~GICR_CTLR_ENABLE_LPIS;
+ writel_relaxed(val, rbase + GICR_CTLR);
+
+ /*
+ * Make sure any change to the table is observable by the GIC.
+ */
+ dsb(sy);
+
+ /* set PROPBASE */
+ val = (page_to_phys(gic_rdists->prop_page) |
+ GICR_PROPBASER_InnerShareable |
+ GICR_PROPBASER_WaWb |
+ ((LPI_NRBITS - 1) & GICR_PROPBASER_IDBITS_MASK));
+
+ writeq_relaxed(val, rbase + GICR_PROPBASER);
+ tmp = readq_relaxed(rbase + GICR_PROPBASER);
+
+ if ((tmp ^ val) & GICR_PROPBASER_SHAREABILITY_MASK) {
+ pr_info_once("GIC: using cache flushing for LPI property table\n");
+ gic_rdists->flags |= RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING;
+ }
+
+ /* set PENDBASE */
+ val = (page_to_phys(pend_page) |
+ GICR_PROPBASER_InnerShareable |
+ GICR_PROPBASER_WaWb);
+
+ writeq_relaxed(val, rbase + GICR_PENDBASER);
+
+ /* Enable LPIs */
+ val = readl_relaxed(rbase + GICR_CTLR);
+ val |= GICR_CTLR_ENABLE_LPIS;
+ writel_relaxed(val, rbase + GICR_CTLR);
+
+ /* Make sure the GIC has seen the above */
+ dsb(sy);
+}
+
+static void its_cpu_init_collection(void)
+{
+ struct its_node *its;
+ int cpu;
+
+ spin_lock(&its_lock);
+ cpu = smp_processor_id();
+
+ list_for_each_entry(its, &its_nodes, entry) {
+ u64 target;
+
+ /*
+ * We now have to bind each collection to its target
+ * redistributor.
+ */
+ if (readq_relaxed(its->base + GITS_TYPER) & GITS_TYPER_PTA) {
+ /*
+ * This ITS wants the physical address of the
+ * redistributor.
+ */
+ target = gic_data_rdist()->phys_base;
+ } else {
+ /*
+ * This ITS wants a linear CPU number.
+ */
+ target = readq_relaxed(gic_data_rdist_rd_base() + GICR_TYPER);
+ target = GICR_TYPER_CPU_NUMBER(target);
+ }
+
+ /* Perform collection mapping */
+ its->collections[cpu].target_address = target;
+ its->collections[cpu].col_id = cpu;
+
+ its_send_mapc(its, &its->collections[cpu], 1);
+ its_send_invall(its, &its->collections[cpu]);
+ }
+
+ spin_unlock(&its_lock);
+}
--
2.1.3

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