[RFC PATCH v3 10/13] soc: ti: Add MSI domain support for K3 Interrupt Aggregator

[Lokesh Vutla]

With the system coprocessor managing the range allocation of the
inputs to Interrupt Aggregator, it is difficult to represent
the device IRQs from DT.

The suggestion is to use MSI in such cases where devices wants
to allocate and group interrupts dynamically.

Create a MSI domain bus layer that allocates and frees MSIs for
a device.

APIs that are implemented are as follows:
- inta_msi_create_irq_domain() that creates a MSI domain
- inta_msi_domain_alloc_group_irqs() that creates MSIs for the
  specified device and source indexes. All these are expected to
  be grouped by the parent interrupt controller to MSI domain.
- inta_msi_domain_free_group_irqs() frees the grouped irqs.

Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
---
- May be the same functionaly can be included in platform msi. But I would
  like to get a feedback on the approach.

Changes since v1:
- New patch

 drivers/soc/ti/Kconfig             |   6 ++
 drivers/soc/ti/Makefile            |   1 +
 drivers/soc/ti/k3_inta_msi.c       | 163 +++++++++++++++++++++++++++++
 include/linux/irqdomain.h          |   1 +
 include/linux/msi.h                |   6 ++
 include/linux/soc/ti/k3_inta_msi.h |  21 ++++
 6 files changed, 198 insertions(+)
 create mode 100644 drivers/soc/ti/k3_inta_msi.c
 create mode 100644 include/linux/soc/ti/k3_inta_msi.h

diff --git a/drivers/soc/ti/Kconfig b/drivers/soc/ti/Kconfig
index be4570baad96..7640490c2a6a 100644
--- a/drivers/soc/ti/Kconfig
+++ b/drivers/soc/ti/Kconfig
@@ -73,4 +73,10 @@ config TI_SCI_PM_DOMAINS
 	  called ti_sci_pm_domains. Note this is needed early in boot before
 	  rootfs may be available.
 
+config K3_INTA_MSI_DOMAIN
+	bool
+	select GENERIC_MSI_IRQ_DOMAIN
+	help
+	  Driver to enable Interrupt Aggregator specific MSI Domain.
+
 endif # SOC_TI
diff --git a/drivers/soc/ti/Makefile b/drivers/soc/ti/Makefile
index a22edc0b258a..152b195273ee 100644
--- a/drivers/soc/ti/Makefile
+++ b/drivers/soc/ti/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_KEYSTONE_NAVIGATOR_DMA)	+= knav_dma.o
 obj-$(CONFIG_AMX3_PM)			+= pm33xx.o
 obj-$(CONFIG_WKUP_M3_IPC)		+= wkup_m3_ipc.o
 obj-$(CONFIG_TI_SCI_PM_DOMAINS)		+= ti_sci_pm_domains.o
+obj-$(CONFIG_K3_INTA_MSI_DOMAIN)	+= k3_inta_msi.o
diff --git a/drivers/soc/ti/k3_inta_msi.c b/drivers/soc/ti/k3_inta_msi.c
new file mode 100644
index 000000000000..0236d836d7f6
--- /dev/null
+++ b/drivers/soc/ti/k3_inta_msi.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Texas Instruments' K3 Interrupt Aggregator driver MSI support
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@xxxxxx>
+ */
+
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/soc/ti/k3_inta_msi.h>
+
+#ifdef GENERIC_MSI_DOMAIN_OPS
+
+#define TI_SCI_DEV_ID_MASK	0xffff
+#define TI_SCI_DEV_ID_SHIFT	16
+#define TI_SCI_IRQ_ID_MASK	0xffff
+#define TI_SCI_IRQ_ID_SHIFT	0
+
+#define TO_HWIRQ(id, index)	(((id & TI_SCI_DEV_ID_MASK) << \
+				 TI_SCI_DEV_ID_SHIFT) | \
+				(index & TI_SCI_IRQ_ID_MASK))
+static void inta_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = TO_HWIRQ(desc->inta.dev_id, desc->inta.msi_index);
+}
+#else
+#define inta_msi_set_desc NULL
+#endif
+
+static void inta_msi_update_dom_ops(struct msi_domain_info *info)
+{
+	struct msi_domain_ops *ops = info->ops;
+
+	BUG_ON(!ops);
+
+	if (ops->set_desc == NULL)
+		ops->set_desc = inta_msi_set_desc;
+}
+
+static void inta_msi_update_chip_ops(struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	BUG_ON(!chip);
+	if (!chip->irq_mask)
+		chip->irq_mask = irq_chip_mask_parent;
+	if (!chip->irq_unmask)
+		chip->irq_unmask = irq_chip_unmask_parent;
+	if (!chip->irq_eoi)
+		chip->irq_eoi = irq_chip_eoi_parent;
+	if (!chip->irq_set_affinity)
+		chip->irq_set_affinity = msi_domain_set_affinity;
+}
+
+struct irq_domain *inta_msi_create_irq_domain(struct fwnode_handle *fwnode,
+					      struct msi_domain_info *info,
+					      struct irq_domain *parent)
+{
+	struct irq_domain *domain;
+
+	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
+		inta_msi_update_dom_ops(info);
+	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
+		inta_msi_update_chip_ops(info);
+
+	domain = msi_create_irq_domain(fwnode, info, parent);
+	if (domain)
+		irq_domain_update_bus_token(domain, DOMAIN_BUS_K3_INTA_MSI);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(inta_msi_create_irq_domain);
+
+static struct msi_desc *inta_msi_alloc_desc(struct device *dev, u32 dev_id,
+					    u32 index)
+{
+	struct msi_desc *msi_desc;
+
+	msi_desc = alloc_msi_entry(dev, 1, NULL);
+	if (!msi_desc) {
+		dev_err(dev, "Failed to allocate msi entry\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	msi_desc->inta.msi_index = index;
+	msi_desc->inta.dev_id = dev_id;
+	INIT_LIST_HEAD(&msi_desc->list);
+	list_add_tail(&msi_desc->list, dev_to_msi_list(dev));
+
+	return msi_desc;
+}
+
+void inta_msi_domain_free_group_irqs(struct device *dev, u32 *arr_index,
+				     int nr_irqs)
+{
+	struct irq_domain *msi_domain;
+	struct msi_desc *desc, *tmp;
+	unsigned int i, virq = 0;
+
+	msi_domain = dev_get_msi_domain(dev);
+
+	list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
+		for (i = 0; i < nr_irqs; i++) {
+			if (desc->inta.msi_index == arr_index[i]) {
+				msi_domain_free_irq(desc);
+				/* HACK to get parent IRQ. Any elegant solution? */
+				if (!virq)
+					virq = desc->msg.data;
+				list_del(&desc->list);
+				free_msi_entry(desc);
+			}
+		}
+	}
+
+	msi_domain_unprepare_irqs(msi_domain, nr_irqs, (void *)&virq);
+}
+EXPORT_SYMBOL_GPL(inta_msi_domain_free_group_irqs);
+
+int inta_msi_domain_alloc_group_irqs(struct device *dev, u32 dev_id,
+				     int nr_irqs, u32 *arr_index)
+{
+	struct irq_domain *msi_domain;
+	struct msi_desc *msi_desc;
+	msi_alloc_info_t arg;
+	int ret, i;
+
+	msi_domain = dev_get_msi_domain(dev);
+	if (!msi_domain)
+		return -EINVAL;
+
+	if (nr_irqs < 1)
+		return -EINVAL;
+
+	ret = msi_domain_prepare_irqs(msi_domain, dev, nr_irqs, &arg);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++) {
+		msi_desc = inta_msi_alloc_desc(dev, dev_id, arr_index[i]);
+		if (IS_ERR(msi_desc)) {
+			ret = PTR_ERR(msi_desc);
+			goto cleanup;
+		}
+
+		ret = msi_domain_alloc_irq(msi_domain, dev, msi_desc, &arg);
+		if (ret) {
+			dev_err(dev, "Failed to allocate IRQs\n");
+			goto cleanup;
+		}
+	}
+	return 0;
+
+cleanup:
+	inta_msi_domain_free_group_irqs(dev, arr_index, i);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(inta_msi_domain_alloc_group_irqs);
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 068aa46f0d55..47bb695e1067 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -81,6 +81,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_NEXUS,
 	DOMAIN_BUS_IPI,
 	DOMAIN_BUS_FSL_MC_MSI,
+	DOMAIN_BUS_K3_INTA_MSI,
 };
 
 /**
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 1e37aa569a3c..acc2873bb197 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -47,6 +47,11 @@ struct fsl_mc_msi_desc {
 	u16				msi_index;
 };
 
+struct inta_msi_desc {
+	u16	dev_id;
+	u16	msi_index;
+};
+
 /**
  * struct msi_desc - Descriptor structure for MSI based interrupts
  * @list:	List head for management
@@ -106,6 +111,7 @@ struct msi_desc {
 		 */
 		struct platform_msi_desc platform;
 		struct fsl_mc_msi_desc fsl_mc;
+		struct inta_msi_desc inta;
 	};
 };
 
diff --git a/include/linux/soc/ti/k3_inta_msi.h b/include/linux/soc/ti/k3_inta_msi.h
new file mode 100644
index 000000000000..42c6202f044d
--- /dev/null
+++ b/include/linux/soc/ti/k3_inta_msi.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Texas Instruments' K3 INTA MSI helper
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@xxxxxx>
+ */
+
+#ifndef __INCLUDE_LINUX_K3_INTA_MSI_H
+#define __INCLUDE_LINUX_K3_INTA_MSI_H
+
+#include <linux/msi.h>
+
+struct irq_domain *inta_msi_create_irq_domain(struct fwnode_handle *fwnode,
+					      struct msi_domain_info *info,
+					      struct irq_domain *parent);
+int inta_msi_domain_alloc_group_irqs(struct device *dev, u32 dev_id,
+				     int nr_irqs, u32 *arr_index);
+void inta_msi_domain_free_group_irqs(struct device *dev, u32 *arr_index,
+				     int nr_irqs);
+#endif /* __INCLUDE_LINUX_IRQCHIP_TI_SCI_INTA_H */
-- 
2.19.1