irqchip/mbigen: Add ACPI support

With the preparation of platform msi support and interrupt producer
in commit d44fa3d460 ("ACPI: Add support for ResourceSource/IRQ
domain mapping"), we can add mbigen ACPI support now.

Now that the major framework changes are ready, we just need to add
the ACPI probe code which creates the irqdomain for devices connecting
to it.

In order to create the irqdomain, we need to know the number of hw
irqs as input which is provided by mbigen. In DT case, we are using
"num-pins" property to describe it, and we will take advantage of
that too using _DSD in ACPI as there is no standard way of describe
it in ACPI way, also according to the _DSD rule described in
Documentation/acpi/DSD-properties-rules.txt, it doesn't break
the rules.

The DSDT is represented as below:

For mbigen,
  Device(MBI0) {
          Name(_HID, "HISI0152")
          Name(_UID, Zero)
          Name(_CRS, ResourceTemplate() {
                  Memory32Fixed(ReadWrite, 0xa0080000, 0x10000)
          })

         Name(_DSD, Package () {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
                         Package () {"num-pins", 378}
                 }
        })
 }

For devices,
 Device(SAS0) {
         Name(_HID, "HISIxxxx")
         Name(_UID, Zero)
         Name(_CRS, ResourceTemplate() {
                 Memory32Fixed(ReadWrite, 0xb0030000, 0x10000)
		 Interrupt(ResourceConsumer,..., "\_SB.MBI0") {12, ...}
         })
 }

So for the devices connected to the mbigen, as we clearly say that
it refers to a specific interrupt controller (mbigen), we can get
the virq from mbigen's irqdomain once it's created successfully.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: MaJun <majun258@huawei.com>
Cc: Al Stone <ahs3@redhat.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-mbigen.c

@@ -16,6 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/acpi.h>
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
 #include <linux/module.h>
@@ -180,7 +181,7 @@ static int mbigen_domain_translate(struct irq_domain *d,
 				    unsigned long *hwirq,
 				    unsigned int *type)
 {
-	if (is_of_node(fwspec->fwnode)) {
+	if (is_of_node(fwspec->fwnode) || is_acpi_device_node(fwspec->fwnode)) {
 		if (fwspec->param_count != 2)
 			return -EINVAL;
 
@@ -271,6 +272,58 @@ static int mbigen_of_create_domain(struct platform_device *pdev,
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+static int mbigen_acpi_create_domain(struct platform_device *pdev,
+				     struct mbigen_device *mgn_chip)
+{
+	struct irq_domain *domain;
+	u32 num_pins = 0;
+	int ret;
+
+	/*
+	 * "num-pins" is the total number of interrupt pins implemented in
+	 * this mbigen instance, and mbigen is an interrupt controller
+	 * connected to ITS  converting wired interrupts into MSI, so we
+	 * use "num-pins" to alloc MSI vectors which are needed by client
+	 * devices connected to it.
+	 *
+	 * Here is the DSDT device node used for mbigen in firmware:
+	 *	Device(MBI0) {
+	 *		Name(_HID, "HISI0152")
+	 *		Name(_UID, Zero)
+	 *		Name(_CRS, ResourceTemplate() {
+	 *			Memory32Fixed(ReadWrite, 0xa0080000, 0x10000)
+	 *		})
+	 *
+	 *		Name(_DSD, Package () {
+	 *			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+	 *			Package () {
+	 *				Package () {"num-pins", 378}
+	 *			}
+	 *		})
+	 *	}
+	 */
+	ret = device_property_read_u32(&pdev->dev, "num-pins", &num_pins);
+	if (ret || num_pins == 0)
+		return -EINVAL;
+
+	domain = platform_msi_create_device_domain(&pdev->dev, num_pins,
+						   mbigen_write_msg,
+						   &mbigen_domain_ops,
+						   mgn_chip);
+	if (!domain)
+		return -ENOMEM;
+
+	return 0;
+}
+#else
+static inline int mbigen_acpi_create_domain(struct platform_device *pdev,
+					    struct mbigen_device *mgn_chip)
+{
+	return -ENODEV;
+}
+#endif
+
 static int mbigen_device_probe(struct platform_device *pdev)
 {
 	struct mbigen_device *mgn_chip;
@@ -289,9 +342,18 @@ static int mbigen_device_probe(struct platform_device *pdev)
 	if (IS_ERR(mgn_chip->base))
 		return PTR_ERR(mgn_chip->base);
 
-	err = mbigen_of_create_domain(pdev, mgn_chip);
+	if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node)
-	if (err)
+		err = mbigen_of_create_domain(pdev, mgn_chip);
+	else if (ACPI_COMPANION(&pdev->dev))
+		err = mbigen_acpi_create_domain(pdev, mgn_chip);
+	else
+		err = -EINVAL;
+
+	if (err) {
+		dev_err(&pdev->dev, "Failed to create mbi-gen@%p irqdomain",
+			mgn_chip->base);
 		return err;
+	}
 
 	platform_set_drvdata(pdev, mgn_chip);
 	return 0;
@@ -303,10 +365,17 @@ static const struct of_device_id mbigen_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mbigen_of_match);
 
+static const struct acpi_device_id mbigen_acpi_match[] = {
+	{ "HISI0152", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, mbigen_acpi_match);
+
 static struct platform_driver mbigen_platform_driver = {
 	.driver = {
 		.name		= "Hisilicon MBIGEN-V2",
 		.of_match_table	= mbigen_of_match,
+		.acpi_match_table = ACPI_PTR(mbigen_acpi_match),
 	},
 	.probe			= mbigen_device_probe,
 };