From: Chen Wang <unicorn_wang@outlook.com>

Add driver for Sophgo SG2042 MSI interrupt controller.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
---
 drivers/irqchip/Kconfig          |   8 +
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-sg2042-msi.c | 255 +++++++++++++++++++++++++++++++
 3 files changed, 264 insertions(+)
 create mode 100644 drivers/irqchip/irq-sg2042-msi.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index d82bcab233a1..76a38a4d62eb 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -729,6 +729,14 @@ config MCHP_EIC
 	help
 	  Support for Microchip External Interrupt Controller.
 
+config SOPHGO_SG2042_MSI
+	bool "Sophgo SG2042 MSI controller"
+	depends on ARCH_SOPHGO || COMPILE_TEST
+	help
+	  Support for the Sophgo SG2042 MSI Controller.
+	  This on-chip interrupt controller enables MSI sources to be
+	  routed to the primary PLIC controller on SoC.
+
 config SUNPLUS_SP7021_INTC
 	bool "Sunplus SP7021 interrupt controller" if COMPILE_TEST
 	default SOC_SP7021
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e3679ec2b9f7..53617890268a 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -125,4 +125,5 @@ obj-$(CONFIG_WPCM450_AIC)		+= irq-wpcm450-aic.o
 obj-$(CONFIG_IRQ_IDT3243X)		+= irq-idt3243x.o
 obj-$(CONFIG_APPLE_AIC)			+= irq-apple-aic.o
 obj-$(CONFIG_MCHP_EIC)			+= irq-mchp-eic.o
+obj-$(CONFIG_SOPHGO_SG2042_MSI)		+= irq-sg2042-msi.o
 obj-$(CONFIG_SUNPLUS_SP7021_INTC)	+= irq-sp7021-intc.o
diff --git a/drivers/irqchip/irq-sg2042-msi.c b/drivers/irqchip/irq-sg2042-msi.c
new file mode 100644
index 000000000000..79449f974ed5
--- /dev/null
+++ b/drivers/irqchip/irq-sg2042-msi.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SG2042 MSI Controller
+ *
+ * Copyright (C) 2024 Sophgo Technology Inc.
+ * Copyright (C) 2024 Chen Wang <unicorn_wang@outlook.com>
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct sg2042_msi_data {
+	void __iomem	*reg_clr; /* clear reg, see TRM, 10.1.33, GP_INTR0_CLR */
+
+	u64		doorbell_addr; /* see TRM, 10.1.32, GP_INTR0_SET */
+
+	u32		irq_first; /* The vector number that MSIs starts */
+	u32		num_irqs;  /* The number of vectors for MSIs */
+
+	unsigned long	*msi_map;
+	struct mutex	msi_map_lock; /* lock for msi_map */
+};
+
+static int sg2042_msi_allocate_hwirq(struct sg2042_msi_data *priv, int num_req)
+{
+	int first;
+
+	mutex_lock(&priv->msi_map_lock);
+
+	first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
+					get_count_order(num_req));
+	if (first < 0) {
+		mutex_unlock(&priv->msi_map_lock);
+		return -ENOSPC;
+	}
+
+	mutex_unlock(&priv->msi_map_lock);
+
+	return priv->irq_first + first;
+}
+
+static void sg2042_msi_free_hwirq(struct sg2042_msi_data *priv,
+				  int hwirq, int num_req)
+{
+	int first = hwirq - priv->irq_first;
+
+	mutex_lock(&priv->msi_map_lock);
+	bitmap_release_region(priv->msi_map, first, get_count_order(num_req));
+	mutex_unlock(&priv->msi_map_lock);
+}
+
+static void sg2042_msi_irq_ack(struct irq_data *d)
+{
+	struct sg2042_msi_data *data  = irq_data_get_irq_chip_data(d);
+	int bit_off = d->hwirq - data->irq_first;
+
+	writel(1 << bit_off, (unsigned int *)data->reg_clr);
+
+	irq_chip_ack_parent(d);
+}
+
+static void sg2042_msi_irq_compose_msi_msg(struct irq_data *data,
+					   struct msi_msg *msg)
+{
+	struct sg2042_msi_data *priv = irq_data_get_irq_chip_data(data);
+
+	msg->address_hi = upper_32_bits(priv->doorbell_addr);
+	msg->address_lo = lower_32_bits(priv->doorbell_addr);
+	msg->data = 1 << (data->hwirq - priv->irq_first);
+
+	pr_debug("%s hwirq[%d]: address_hi[%#x], address_lo[%#x], data[%#x]\n",
+		 __func__,
+		 (int)data->hwirq, msg->address_hi, msg->address_lo, msg->data);
+}
+
+static struct irq_chip sg2042_msi_middle_irq_chip = {
+	.name			= "SG2042 MSI",
+	.irq_ack		= sg2042_msi_irq_ack,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+#ifdef CONFIG_SMP
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+#endif
+	.irq_compose_msi_msg	= sg2042_msi_irq_compose_msi_msg,
+};
+
+static int sg2042_msi_parent_domain_alloc(struct irq_domain *domain,
+					  unsigned int virq, int hwirq)
+{
+	struct irq_fwspec fwspec;
+	struct irq_data *d;
+	int ret;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 2;
+	fwspec.param[0] = hwirq;
+	fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (ret)
+		return ret;
+
+	d = irq_domain_get_irq_data(domain->parent, virq);
+	return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
+}
+
+static int sg2042_msi_middle_domain_alloc(struct irq_domain *domain,
+					  unsigned int virq,
+					  unsigned int nr_irqs, void *args)
+{
+	struct sg2042_msi_data *priv = domain->host_data;
+	int hwirq, err, i;
+
+	hwirq = sg2042_msi_allocate_hwirq(priv, nr_irqs);
+	if (hwirq < 0)
+		return hwirq;
+
+	for (i = 0; i < nr_irqs; i++) {
+		err = sg2042_msi_parent_domain_alloc(domain, virq + i, hwirq + i);
+		if (err)
+			goto err_hwirq;
+
+		pr_debug("%s: virq[%d], hwirq[%d]\n",
+			 __func__, virq + i, (int)hwirq + i);
+
+		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+					      &sg2042_msi_middle_irq_chip, priv);
+	}
+
+	return 0;
+
+err_hwirq:
+	sg2042_msi_free_hwirq(priv, hwirq, nr_irqs);
+	irq_domain_free_irqs_parent(domain, virq, i);
+
+	return err;
+}
+
+static void sg2042_msi_middle_domain_free(struct irq_domain *domain,
+					  unsigned int virq,
+					  unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct sg2042_msi_data *priv = irq_data_get_irq_chip_data(d);
+
+	irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+	sg2042_msi_free_hwirq(priv, d->hwirq, nr_irqs);
+}
+
+static const struct irq_domain_ops pch_msi_middle_domain_ops = {
+	.alloc	= sg2042_msi_middle_domain_alloc,
+	.free	= sg2042_msi_middle_domain_free,
+};
+
+static int sg2042_msi_init_domains(struct sg2042_msi_data *priv,
+				   struct device_node *node)
+{
+	struct irq_domain *plic_domain, *middle_domain;
+	struct device_node *plic_node;
+	struct fwnode_handle *fwnode = of_node_to_fwnode(node);
+
+	if (!of_find_property(node, "interrupt-parent", NULL)) {
+		pr_err("Can't find interrupt-parent!\n");
+		return -EINVAL;
+	}
+
+	plic_node = of_irq_find_parent(node);
+	if (!plic_node) {
+		pr_err("Failed to find the PLIC node!\n");
+		return -ENXIO;
+	}
+
+	plic_domain = irq_find_host(plic_node);
+	of_node_put(plic_node);
+	if (!plic_domain) {
+		pr_err("Failed to find the PLIC domain\n");
+		return -ENXIO;
+	}
+
+	middle_domain = irq_domain_create_hierarchy(plic_domain, 0, priv->num_irqs,
+						    fwnode,
+						    &pch_msi_middle_domain_ops,
+						    priv);
+	if (!middle_domain) {
+		pr_err("Failed to create the MSI middle domain\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int sg2042_msi_probe(struct platform_device *pdev)
+{
+	struct sg2042_msi_data *data;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(struct sg2042_msi_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->reg_clr = devm_platform_ioremap_resource_byname(pdev, "clr");
+	if (IS_ERR(data->reg_clr)) {
+		dev_err(&pdev->dev, "Failed to map clear register\n");
+		return PTR_ERR(data->reg_clr);
+	}
+
+	if (of_property_read_u64(pdev->dev.of_node, "sophgo,msi-doorbell-addr",
+				 &data->doorbell_addr)) {
+		dev_err(&pdev->dev, "Unable to parse MSI doorbell addr\n");
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(pdev->dev.of_node, "sophgo,msi-base-vec",
+				 &data->irq_first)) {
+		dev_err(&pdev->dev, "Unable to parse MSI vec base\n");
+		return -EINVAL;
+	}
+
+	if (of_property_read_u32(pdev->dev.of_node, "sophgo,msi-num-vecs",
+				 &data->num_irqs)) {
+		dev_err(&pdev->dev, "Unable to parse MSI vec number\n");
+		return -EINVAL;
+	}
+
+	mutex_init(&data->msi_map_lock);
+
+	data->msi_map = bitmap_zalloc(data->num_irqs, GFP_KERNEL);
+	if (!data->msi_map)
+		return -ENOMEM;
+
+	return sg2042_msi_init_domains(data, pdev->dev.of_node);
+}
+
+static const struct of_device_id sg2042_msi_of_match[] = {
+	{ .compatible = "sophgo,sg2042-msi" },
+	{}
+};
+
+static struct platform_driver sg2042_msi_driver = {
+	.driver = {
+		.name = "sg2042-msi",
+		.of_match_table = of_match_ptr(sg2042_msi_of_match),
+	},
+	.probe = sg2042_msi_probe,
+};
+builtin_platform_driver(sg2042_msi_driver);
-- 
2.34.1

On Mon, Nov 11 2024 at 12:01, Chen Wang wrote:
> +struct sg2042_msi_data {
> +	void __iomem	*reg_clr; /* clear reg, see TRM, 10.1.33, GP_INTR0_CLR */

Please make these tail comments tabular aligned so they actually stand
out.

  https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#comment-style

> +
> +	u64		doorbell_addr; /* see TRM, 10.1.32, GP_INTR0_SET */
> +
> +	u32		irq_first; /* The vector number that MSIs starts */
> +	u32		num_irqs;  /* The number of vectors for MSIs */
> +
> +	unsigned long	*msi_map;
> +	struct mutex	msi_map_lock; /* lock for msi_map */
> +};
> +
> +static int sg2042_msi_allocate_hwirq(struct sg2042_msi_data *priv, int num_req)
> +{
> +	int first;
> +
> +	mutex_lock(&priv->msi_map_lock);

Please use

       guard(mutex)(&priv->msi_map_lock);

which removes all the mutex_unlock() hackery and boils this down

> +
> +	first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
> +					get_count_order(num_req));
> +	if (first < 0) {
> +		mutex_unlock(&priv->msi_map_lock);
> +		return -ENOSPC;
> +	}
> +
> +	mutex_unlock(&priv->msi_map_lock);
> +
> +	return priv->irq_first + first;

to

	guard(mutex)(&priv->msi_map_lock);
	first = bitmap_find_free_region(priv->msi_map, priv->num_irqs,
					get_count_order(num_req));
	return first >= 0 ? priv->irq_first + first : -ENOSPC;

See?

> +}
> +
> +static void sg2042_msi_free_hwirq(struct sg2042_msi_data *priv,
> +				  int hwirq, int num_req)
> +{
> +	int first = hwirq - priv->irq_first;
> +
> +	mutex_lock(&priv->msi_map_lock);

Ditto.

> +	bitmap_release_region(priv->msi_map, first, get_count_order(num_req));
> +	mutex_unlock(&priv->msi_map_lock);
> +}

> +static void sg2042_msi_irq_compose_msi_msg(struct irq_data *data,
> +					   struct msi_msg *msg)
> +{
> +	struct sg2042_msi_data *priv = irq_data_get_irq_chip_data(data);
> +
> +	msg->address_hi = upper_32_bits(priv->doorbell_addr);
> +	msg->address_lo = lower_32_bits(priv->doorbell_addr);
> +	msg->data = 1 << (data->hwirq - priv->irq_first);
> +
> +	pr_debug("%s hwirq[%d]: address_hi[%#x], address_lo[%#x], data[%#x]\n",
> +		 __func__,

No point in having this line break. You have 100 characters. Please fix
this all over the place.

> +		 (int)data->hwirq, msg->address_hi, msg->address_lo, msg->data);

(int) ? Why can't you use the proper conversion specifier instead of %d?

> +static int sg2042_msi_middle_domain_alloc(struct irq_domain *domain,
> +					  unsigned int virq,
> +					  unsigned int nr_irqs, void *args)
> +{
> +	struct sg2042_msi_data *priv = domain->host_data;
> +	int hwirq, err, i;
> +
> +	hwirq = sg2042_msi_allocate_hwirq(priv, nr_irqs);
> +	if (hwirq < 0)
> +		return hwirq;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		err = sg2042_msi_parent_domain_alloc(domain, virq + i, hwirq + i);
> +		if (err)
> +			goto err_hwirq;
> +
> +		pr_debug("%s: virq[%d], hwirq[%d]\n",
> +			 __func__, virq + i, (int)hwirq + i);

No line break required.

> +		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> +					      &sg2042_msi_middle_irq_chip, priv);
> +	}

> +static int sg2042_msi_init_domains(struct sg2042_msi_data *priv,
> +				   struct device_node *node)
> +{
> +	struct irq_domain *plic_domain, *middle_domain;
> +	struct device_node *plic_node;
> +	struct fwnode_handle *fwnode = of_node_to_fwnode(node);

https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#variable-declarations

> +	if (!of_find_property(node, "interrupt-parent", NULL)) {
> +		pr_err("Can't find interrupt-parent!\n");
> +		return -EINVAL;
> +	}
> +
> +	plic_node = of_irq_find_parent(node);
> +	if (!plic_node) {
> +		pr_err("Failed to find the PLIC node!\n");
> +		return -ENXIO;
> +	}
> +
> +	plic_domain = irq_find_host(plic_node);
> +	of_node_put(plic_node);
> +	if (!plic_domain) {
> +		pr_err("Failed to find the PLIC domain\n");
> +		return -ENXIO;
> +	}
> +
> +	middle_domain = irq_domain_create_hierarchy(plic_domain, 0, priv->num_irqs,
> +						    fwnode,
> +						    &pch_msi_middle_domain_ops,
> +						    priv);

So now you have created a domain. How is that supposed to be used by the
PCI layer?

> +	if (!middle_domain) {
> +		pr_err("Failed to create the MSI middle domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}

> +static int sg2042_msi_probe(struct platform_device *pdev)
> +{

....

> +	data->msi_map = bitmap_zalloc(data->num_irqs, GFP_KERNEL);
> +	if (!data->msi_map)
> +		return -ENOMEM;
> +
> +	return sg2042_msi_init_domains(data, pdev->dev.of_node);

In case of error this leaks data->msi_map, no?

> +static struct platform_driver sg2042_msi_driver = {
> +	.driver = {
> +		.name = "sg2042-msi",
> +		.of_match_table = of_match_ptr(sg2042_msi_of_match),
> +	},
> +	.probe = sg2042_msi_probe,
> +};

Please see the documentation I pointed you to above and search for
struct initializers.

Thanks,

        tglx