[PATCH v9 07/15] irqchip: gicv3-its: platform-msi: scan MADT to create platform msi domain

[Hanjun Guo]

From: Hanjun Guo <hanjun.guo at linaro.org>

With the introduction of its_pmsi_init_one(), support for ACPI
firmware interface can be plugged into the gicv3 ITS driver.

Add code to scan the MADT table to get the ITS entry(ies), then use
the information to create the platform msi domain for devices
connected to it, mirroring the ITS PCI MSI code path.

Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
[lorenzo.pieralisi at arm.com: rewrote commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Reviewed-by: Matthias Brugger <mbrugger at suse.com>
Tested-by: Ming Lei <ming.lei at canonical.com>
Tested-by: Wei Xu <xuwei5 at hisilicon.com>
Tested-by: Sinan Kaya <okaya at codeaurora.org>
Cc: Marc Zyngier <marc.zyngier at arm.com>
Cc: Tomasz Nowicki <tn at semihalf.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
---
 drivers/irqchip/irq-gic-v3-its-platform-msi.c | 37 +++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its-platform-msi.c b/drivers/irqchip/irq-gic-v3-its-platform-msi.c
index 3d9efd1..e4ba9f4 100644
--- a/drivers/irqchip/irq-gic-v3-its-platform-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-platform-msi.c
@@ -15,6 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/acpi_iort.h>
 #include <linux/device.h>
 #include <linux/msi.h>
 #include <linux/of.h>
@@ -103,6 +104,41 @@ static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+static int __init
+its_pmsi_parse_madt(struct acpi_subtable_header *header,
+			const unsigned long end)
+{
+	struct acpi_madt_generic_translator *its_entry;
+	struct fwnode_handle *domain_handle;
+	const char *node_name;
+	int err = -ENXIO;
+
+	its_entry = (struct acpi_madt_generic_translator *)header;
+	node_name = kasprintf(GFP_KERNEL, "ITS at 0x%lx",
+			      (long)its_entry->base_address);
+	domain_handle = iort_find_domain_token(its_entry->translation_id);
+	if (!domain_handle) {
+		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
+		goto out;
+	}
+
+	err = its_pmsi_init_one(domain_handle, node_name);
+
+out:
+	kfree(node_name);
+	return err;
+}
+
+static void __init its_pmsi_acpi_init(void)
+{
+	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
+			      its_pmsi_parse_madt, 0);
+}
+#else
+static inline void its_pmsi_acpi_init(void) { }
+#endif
+
 static void __init its_pmsi_of_init(void)
 {
 	struct device_node *np;
@@ -119,6 +155,7 @@ static void __init its_pmsi_of_init(void)
 static int __init its_pmsi_init(void)
 {
 	its_pmsi_of_init();
+	its_pmsi_acpi_init();
 	return 0;
 }
 early_initcall(its_pmsi_init);
-- 
1.7.12.4