From f785f7d2e37872a3aada7e4a399388bb68f43136 Mon Sep 17 00:00:00 2001
From: Hanjun Guo <hanjun.guo@linaro.org>
Date: Tue, 7 Mar 2017 20:40:02 +0800
Subject: [PATCH] irqchip/gicv3-its: platform-msi: Scan MADT to create platform
 msi domain

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@linaro.org>
[lorenzo.pieralisi@arm.com: rewrote commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Tested-by: Sinan Kaya <okaya@codeaurora.org>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 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 3d9efd14a63f..e4ba9f4cbd1a 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@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);
-- 
2.20.1