[RFC PATCH v3 21/37] irqchip: Add irq-kvx-apic-mailbox driver

ysionneau
2024-07-22T09:43:37Z

From: Yann Sionneau <ysionneau@kalrayinc.com>

The APIC includes a mailbox controller, containing 128 mailboxes.
Each mailbox is an 8-byte word.
Each mailbox can be independently configured with a trigger condition
and an input function.
After a write to a mailbox if the trigger condition is met, an
interrupt will be generated.
Since this hardware block generates IRQs based on writes at some memory
locations, it is both an interrupt-controller and an MSI controller.

Co-developed-by: Clement Leger <clement@clement-leger.fr>
Signed-off-by: Clement Leger <clement@clement-leger.fr>
Co-developed-by: Jules Maselbas <jmaselbas@zdiv.net>
Signed-off-by: Jules Maselbas <jmaselbas@zdiv.net>
Co-developed-by: Julian Vetter <jvetter@kalrayinc.com>
Signed-off-by: Julian Vetter <jvetter@kalrayinc.com>
Co-developed-by: Luc Michel <luc@lmichel.fr>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Signed-off-by: Yann Sionneau <ysionneau@kalrayinc.com>
---

Notes:
V1 -> V2:
- new patch
- removed print on probe success

V2 -> V3: update compatible
---
drivers/irqchip/Kconfig | 8 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-kvx-apic-mailbox.c | 480 +++++++++++++++++++++++++
3 files changed, 489 insertions(+)
create mode 100644 drivers/irqchip/irq-kvx-apic-mailbox.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index bf06506d611d5..dbac5b4400e02 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -346,6 +346,14 @@ config KVX_ITGEN
select IRQ_DOMAIN
select IRQ_DOMAIN_HIERARCHY

+config KVX_APIC_MAILBOX
+ bool
+ depends on KVX
+ select GENERIC_IRQ_IPI if SMP
+ select GENERIC_MSI_IRQ_DOMAIN
+ select IRQ_DOMAIN
+ select IRQ_DOMAIN_HIERARCHY
+
config INGENIC_IRQ
bool
depends on MACH_INGENIC
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index b2c514faf9bf7..16a2f666b788d 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_KEYSTONE_IRQ) += irq-keystone.o
obj-$(CONFIG_MIPS_GIC) += irq-mips-gic.o
obj-$(CONFIG_KVX_APIC_GIC) += irq-kvx-apic-gic.o
obj-$(CONFIG_KVX_ITGEN) += irq-kvx-itgen.o
+obj-$(CONFIG_KVX_APIC_MAILBOX) += irq-kvx-apic-mailbox.o
obj-$(CONFIG_ARCH_MEDIATEK) += irq-mtk-sysirq.o irq-mtk-cirq.o
obj-$(CONFIG_ARCH_DIGICOLOR) += irq-digicolor.o
obj-$(CONFIG_ARCH_SA1100) += irq-sa11x0.o
diff --git a/drivers/irqchip/irq-kvx-apic-mailbox.c b/drivers/irqchip/irq-kvx-apic-mailbox.c
new file mode 100644
index 0000000000000..6f0e9134db2ff
--- /dev/null
+++ b/drivers/irqchip/irq-kvx-apic-mailbox.c
@@ -0,0 +1,480 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ * Jules Maselbas
+ */
+
+#define pr_fmt(fmt) "kvx_apic_mailbox: " fmt
+
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/iommu.h>
+#include <linux/irqchip.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/init.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+
+#define KVX_MAILBOX_MODE_WRITE 0x0
+#define KVX_MAILBOX_MODE_OR 0x1
+#define KVX_MAILBOX_MODE_ADD 0x2
+
+#define KVX_MAILBOX_TRIG_NO_TRIG 0x0
+#define KVX_MAILBOX_TRIG_DOORBELL 0x1
+#define KVX_MAILBOX_TRIG_MATCH 0x2
+#define KVX_MAILBOX_TRIG_BARRIER 0x3
+#define KVX_MAILBOX_TRIG_THRESHOLD 0x4
+
+#define KVX_MAILBOX_OFFSET 0x0
+#define KVX_MAILBOX_ELEM_SIZE 0x200
+#define KVX_MAILBOX_MASK_OFFSET 0x10
+#define KVX_MAILBOX_FUNCT_OFFSET 0x18
+#define KVX_MAILBOX_LAC_OFFSET 0x8
+#define KVX_MAILBOX_VALUE_OFFSET 0x0
+#define KVX_MAILBOX_FUNCT_MODE_SHIFT 0x0
+#define KVX_MAILBOX_FUNCT_TRIG_SHIFT 0x8
+
+#define MAILBOXES_MAX_COUNT 128
+
+/* Mailboxes are 64 bits wide */
+#define MAILBOXES_BIT_SIZE 64
+
+/* Maximum number of mailboxes available */
+#define MAILBOXES_MAX_BIT_COUNT (MAILBOXES_MAX_COUNT * MAILBOXES_BIT_SIZE)
+
+/* Mailboxes are grouped by 8 in a single page */
+#define MAILBOXES_BITS_PER_PAGE (8 * MAILBOXES_BIT_SIZE)
+
+/**
+ * struct mb_data - per mailbox data
+ * @cpu: CPU on which the mailbox is routed
+ * @parent_irq: Parent IRQ on the GIC
+ */
+struct mb_data {
+ unsigned int cpu;
+ unsigned int parent_irq;
+};
+
+/**
+ * struct kvx_apic_mailbox - kvx apic mailbox
+ * @base: base address of the controller
+ * @device_domain: IRQ device domain for mailboxes
+ * @msi_domain: platform MSI domain for MSI interface
+ * @domain_info: Domain information needed for the MSI domain
+ * @mb_count: Count of mailboxes we are handling
+ * @available: bitmap of availables bits in mailboxes
+ * @mailboxes_lock: lock for irq migration
+ * @mask_lock: lock for irq masking
+ * @mb_data: data associated to each mailbox
+ */
+struct kvx_apic_mailbox {
+ void __iomem *base;
+ phys_addr_t phys_base;
+ struct irq_domain *device_domain;
+ struct irq_domain *msi_domain;
+ struct msi_domain_info domain_info;
+ /* Start and count of device mailboxes */
+ unsigned int mb_count;
+ /* Bitmap of allocated bits in mailboxes */
+ DECLARE_BITMAP(available, MAILBOXES_MAX_BIT_COUNT);
+ spinlock_t mailboxes_lock;
+ raw_spinlock_t mask_lock;
+ struct mb_data mb_data[MAILBOXES_MAX_COUNT];
+};
+
+/**
+ * struct kvx_irq_data - per irq data
+ * @mb: Mailbox structure
+ */
+struct kvx_irq_data {
+ struct kvx_apic_mailbox *mb;
+};
+
+static void kvx_mailbox_get_from_hwirq(unsigned int hw_irq,
+ unsigned int *mailbox_num,
+ unsigned int *mailbox_bit)
+{
+ *mailbox_num = hw_irq / MAILBOXES_BIT_SIZE;
+ *mailbox_bit = hw_irq % MAILBOXES_BIT_SIZE;
+}
+
+static void __iomem *kvx_mailbox_get_addr(struct kvx_apic_mailbox *mb,
+ unsigned int num)
+{
+ return mb->base + (num * KVX_MAILBOX_ELEM_SIZE);
+}
+
+static phys_addr_t kvx_mailbox_get_phys_addr(struct kvx_apic_mailbox *mb,
+ unsigned int num)
+{
+ return mb->phys_base + (num * KVX_MAILBOX_ELEM_SIZE);
+}
+
+static void kvx_mailbox_msi_compose_msg(struct irq_data *data,
+ struct msi_msg *msg)
+{
+ struct kvx_irq_data *kd = irq_data_get_irq_chip_data(data);
+ struct kvx_apic_mailbox *mb = kd->mb;
+ unsigned int mb_num, mb_bit;
+ phys_addr_t mb_addr;
+
+ kvx_mailbox_get_from_hwirq(irqd_to_hwirq(data), &mb_num, &mb_bit);
+ mb_addr = kvx_mailbox_get_phys_addr(mb, mb_num);
+
+ msg->address_hi = upper_32_bits(mb_addr);
+ msg->address_lo = lower_32_bits(mb_addr);
+ msg->data = mb_bit;
+
+ iommu_dma_compose_msi_msg(irq_data_get_msi_desc(data), msg);
+}
+
+static void kvx_mailbox_set_irq_enable(struct irq_data *data,
+ bool enabled)
+{
+ struct kvx_irq_data *kd = irq_data_get_irq_chip_data(data);
+ struct kvx_apic_mailbox *mb = kd->mb;
+ unsigned int mb_num, mb_bit;
+ void __iomem *mb_addr;
+ u64 mask_value, mb_value;
+
+ kvx_mailbox_get_from_hwirq(irqd_to_hwirq(data), &mb_num, &mb_bit);
+ mb_addr = kvx_mailbox_get_addr(mb, mb_num);
+
+ raw_spin_lock(&mb->mask_lock);
+ mask_value = readq(mb_addr + KVX_MAILBOX_MASK_OFFSET);
+ if (enabled)
+ mask_value |= BIT_ULL(mb_bit);
+ else
+ mask_value &= ~BIT_ULL(mb_bit);
+
+ writeq(mask_value, mb_addr + KVX_MAILBOX_MASK_OFFSET);
+
+ raw_spin_unlock(&mb->mask_lock);
+
+ /**
+ * Since interrupts on mailboxes are edge triggered and are only
+ * triggered when writing the value, we need to trigger it manually
+ * after updating the mask if enabled. If the interrupt was triggered by
+ * the device just after the mask write, we can trigger a spurious
+ * interrupt but that is still better than missing one...
+ * Moreover, the mailbox is configured in OR mode which means that even
+ * if we write a single bit, all other bits will be kept intact.
+ */
+ if (enabled) {
+ mb_value = readq(mb_addr + KVX_MAILBOX_VALUE_OFFSET);
+ if (mb_value & BIT_ULL(mb_bit))
+ writeq(BIT_ULL(mb_bit),
+ mb_addr + KVX_MAILBOX_VALUE_OFFSET);
+ }
+}
+
+static void kvx_mailbox_mask(struct irq_data *data)
+{
+ kvx_mailbox_set_irq_enable(data, false);
+}
+
+static void kvx_mailbox_unmask(struct irq_data *data)
+{
+ kvx_mailbox_set_irq_enable(data, true);
+}
+
+static void kvx_mailbox_set_cpu(struct kvx_apic_mailbox *mb, int mb_id,
+ int new_cpu)
+{
+ irq_set_affinity(mb->mb_data[mb_id].parent_irq, cpumask_of(new_cpu));
+ mb->mb_data[mb_id].cpu = new_cpu;
+}
+
+static void kvx_mailbox_free_bit(struct kvx_apic_mailbox *mb, int hw_irq)
+{
+ unsigned int mb_num, mb_bit;
+
+ kvx_mailbox_get_from_hwirq(hw_irq, &mb_num, &mb_bit);
+ bitmap_clear(mb->available, hw_irq, 1);
+
+ /* If there is no more IRQ on this mailbox, reset it to CPU 0 */
+ if (mb->available[mb_num] == 0)
+ kvx_mailbox_set_cpu(mb, mb_num, 0);
+}
+
+struct irq_chip kvx_apic_mailbox_irq_chip = {
+ .name = "kvx apic mailbox",
+ .irq_compose_msi_msg = kvx_mailbox_msi_compose_msg,
+ .irq_mask = kvx_mailbox_mask,
+ .irq_unmask = kvx_mailbox_unmask,
+};
+
+static int kvx_mailbox_allocate_bits(struct kvx_apic_mailbox *mb, int num_req)
+{
+ int first, align_mask = 0;
+
+ /* This must be a power of 2 for bitmap_find_next_zero_area to work */
+ BUILD_BUG_ON((MAILBOXES_BITS_PER_PAGE & (MAILBOXES_BITS_PER_PAGE - 1)));
+
+ /*
+ * If user requested more than 1 mailbox, we must make sure it will be
+ * aligned on a page size for iommu_dma_prepare_msi to be correctly
+ * mapped in a single page.
+ */
+ if (num_req > 1)
+ align_mask = (MAILBOXES_BITS_PER_PAGE - 1);
+
+ spin_lock(&mb->mailboxes_lock);
+
+ first = bitmap_find_next_zero_area(mb->available,
+ mb->mb_count * MAILBOXES_BIT_SIZE, 0,
+ num_req, align_mask);
+ if (first >= MAILBOXES_MAX_BIT_COUNT) {
+ spin_unlock(&mb->mailboxes_lock);
+ return -ENOSPC;
+ }
+
+ bitmap_set(mb->available, first, num_req);
+
+ spin_unlock(&mb->mailboxes_lock);
+
+ return first;
+}
+
+static int kvx_apic_mailbox_msi_alloc(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ int i, err;
+ int hwirq = 0;
+ u64 mb_addr;
+ struct irq_data *d;
+ struct kvx_irq_data *kd;
+ struct kvx_apic_mailbox *mb = domain->host_data;
+ struct msi_alloc_info *msi_info = (struct msi_alloc_info *)args;
+ struct msi_desc *desc = msi_info->desc;
+ unsigned int mb_num, mb_bit;
+
+ /* We will not be able to guarantee page alignment ! */
+ if (nr_irqs > MAILBOXES_BITS_PER_PAGE)
+ return -EINVAL;
+
+ hwirq = kvx_mailbox_allocate_bits(mb, nr_irqs);
+ if (hwirq < 0)
+ return hwirq;
+
+ kvx_mailbox_get_from_hwirq(hwirq, &mb_num, &mb_bit);
+ mb_addr = (u64) kvx_mailbox_get_phys_addr(mb, mb_num);
+ err = iommu_dma_prepare_msi(desc, mb_addr);
+ if (err)
+ goto free_mb_bits;
+
+ for (i = 0; i < nr_irqs; i++) {
+ kd = kmalloc(sizeof(*kd), GFP_KERNEL);
+ if (!kd) {
+ err = -ENOMEM;
+ goto free_irq_data;
+ }
+
+ kd->mb = mb;
+ irq_domain_set_info(domain, virq + i, hwirq + i,
+ &kvx_apic_mailbox_irq_chip,
+ kd, handle_simple_irq,
+ NULL, NULL);
+ }
+
+ return 0;
+
+free_irq_data:
+ for (i--; i >= 0; i--) {
+ d = irq_domain_get_irq_data(domain, virq + i);
+ kd = irq_data_get_irq_chip_data(d);
+ kfree(kd);
+ }
+
+free_mb_bits:
+ spin_lock(&mb->mailboxes_lock);
+ bitmap_clear(mb->available, hwirq, nr_irqs);
+ spin_unlock(&mb->mailboxes_lock);
+
+ return err;
+}
+
+static void kvx_apic_mailbox_msi_free(struct irq_domain *domain,
+ unsigned int virq,
+ unsigned int nr_irqs)
+{
+ int i;
+ struct irq_data *d;
+ struct kvx_irq_data *kd;
+ struct kvx_apic_mailbox *mb = domain->host_data;
+
+ spin_lock(&mb->mailboxes_lock);
+
+ for (i = 0; i < nr_irqs; i++) {
+ d = irq_domain_get_irq_data(domain, virq + i);
+ kd = irq_data_get_irq_chip_data(d);
+ kfree(kd);
+ kvx_mailbox_free_bit(mb, d->hwirq);
+ }
+
+ spin_unlock(&mb->mailboxes_lock);
+}
+
+static const struct irq_domain_ops kvx_apic_mailbox_domain_ops = {
+ .alloc = kvx_apic_mailbox_msi_alloc,
+ .free = kvx_apic_mailbox_msi_free
+};
+
+static struct irq_chip kvx_msi_irq_chip = {
+ .name = "KVX MSI",
+};
+
+static void kvx_apic_mailbox_handle_irq(struct irq_desc *desc)
+{
+ struct irq_data *data = irq_desc_get_irq_data(desc);
+ struct kvx_apic_mailbox *mb = irq_desc_get_handler_data(desc);
+ void __iomem *mb_addr = kvx_mailbox_get_addr(mb, irqd_to_hwirq(data));
+ unsigned int irqn, cascade_irq, bit;
+ u64 mask_value, masked_its;
+ u64 mb_value;
+ /* Since we allocate 64 interrupts for each mailbox, the scheme
+ * to find the hwirq associated to a mailbox irq is the
+ * following:
+ * hw_irq = mb_num * MAILBOXES_BIT_SIZE + bit
+ */
+ unsigned int mb_hwirq = irqd_to_hwirq(data) * MAILBOXES_BIT_SIZE;
+
+ mb_value = readq(mb_addr + KVX_MAILBOX_LAC_OFFSET);
+ mask_value = readq(mb_addr + KVX_MAILBOX_MASK_OFFSET);
+ /* Mask any disabled interrupts */
+ mb_value &= mask_value;
+
+ /**
+ * Write all pending ITs that are masked to process them later
+ * Since the mailbox is in OR mode, these bits will be merged with any
+ * already set bits and thus avoid losing any interrupts.
+ */
+ masked_its = (~mask_value) & mb_value;
+ if (masked_its)
+ writeq(masked_its, mb_addr + KVX_MAILBOX_LAC_OFFSET);
+
+ for_each_set_bit(bit, (unsigned long *) &mb_value, BITS_PER_LONG) {
+ irqn = bit + mb_hwirq;
+ cascade_irq = irq_find_mapping(mb->device_domain, irqn);
+ generic_handle_irq(cascade_irq);
+ }
+}
+
+static void __init
+apic_mailbox_reset(struct kvx_apic_mailbox *mb)
+{
+ unsigned int i;
+ unsigned int mb_end = mb->mb_count;
+ void __iomem *mb_addr;
+ u64 funct_val = (KVX_MAILBOX_MODE_OR << KVX_MAILBOX_FUNCT_MODE_SHIFT) |
+ (KVX_MAILBOX_TRIG_DOORBELL << KVX_MAILBOX_FUNCT_TRIG_SHIFT);
+
+ for (i = 0; i < mb_end; i++) {
+ mb_addr = kvx_mailbox_get_addr(mb, i);
+ /* Disable all interrupts */
+ writeq(0ULL, mb_addr + KVX_MAILBOX_MASK_OFFSET);
+ /* Set mailbox to OR mode + trigger */
+ writeq(funct_val, mb_addr + KVX_MAILBOX_FUNCT_OFFSET);
+ /* Load & Clear mailbox value */
+ readq(mb_addr + KVX_MAILBOX_LAC_OFFSET);
+ }
+}
+
+static struct msi_domain_ops kvx_msi_domain_ops = {
+};
+
+static struct msi_domain_info kvx_msi_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+ .ops = &kvx_msi_domain_ops,
+ .chip = &kvx_msi_irq_chip,
+};
+
+static int __init
+kvx_init_apic_mailbox(struct device_node *node,
+ struct device_node *parent)
+{
+ struct kvx_apic_mailbox *mb;
+ unsigned int parent_irq, irq_count;
+ struct resource res;
+ int ret, i;
+
+ mb = kzalloc(sizeof(*mb), GFP_KERNEL);
+ if (!mb)
+ return -ENOMEM;
+
+ ret = of_address_to_resource(node, 0, &res);
+ if (ret)
+ return -EINVAL;
+
+ mb->phys_base = res.start;
+ mb->base = of_io_request_and_map(node, 0, node->name);
+ if (!mb->base) {
+ ret = -EINVAL;
+ goto err_kfree;
+ }
+
+ spin_lock_init(&mb->mailboxes_lock);
+ raw_spin_lock_init(&mb->mask_lock);
+
+ irq_count = of_irq_count(node);
+ if (irq_count == 0 || irq_count > MAILBOXES_MAX_COUNT) {
+ ret = -EINVAL;
+ goto err_kfree;
+ }
+ mb->mb_count = irq_count;
+
+ apic_mailbox_reset(mb);
+
+ mb->device_domain = irq_domain_add_tree(node,
+ &kvx_apic_mailbox_domain_ops,
+ mb);
+ if (!mb->device_domain) {
+ pr_err("Failed to setup device domain\n");
+ ret = -EINVAL;
+ goto err_iounmap;
+ }
+
+ mb->msi_domain = platform_msi_create_irq_domain(of_node_to_fwnode(node),
+ &kvx_msi_domain_info,
+ mb->device_domain);
+ if (!mb->msi_domain) {
+ ret = -EINVAL;
+ goto err_irq_domain_add_tree;
+ }
+
+ /* Chain all interrupts from gic to mailbox */
+ for (i = 0; i < irq_count; i++) {
+ parent_irq = irq_of_parse_and_map(node, i);
+ if (parent_irq == 0) {
+ pr_err("unable to parse irq\n");
+ ret = -EINVAL;
+ goto err_irq_domain_msi_create;
+ }
+ mb->mb_data[i].parent_irq = parent_irq;
+
+ irq_set_chained_handler_and_data(parent_irq,
+ kvx_apic_mailbox_handle_irq,
+ mb);
+ }
+
+ return 0;
+
+err_irq_domain_msi_create:
+ irq_domain_remove(mb->msi_domain);
+err_irq_domain_add_tree:
+ irq_domain_remove(mb->device_domain);
+err_iounmap:
+ iounmap(mb->base);
+err_kfree:
+ kfree(mb);
+
+ return ret;
+}
+
+IRQCHIP_DECLARE(kvx_apic_mailbox, "kalray,coolidge-apic-mailbox",
+ kvx_init_apic_mailbox);
--
2.45.2