[PATCH 3/3] arm-smmu: use dts passed MSI IOVA address and length

[Shyam Saini <shyamsaini@linux.microsoft.com>]

Currently ARM SMMU drivers hardcode PCI MSI IOVA address.
Not all the platform have same memory mappings and some platform
could have this address already being mapped for something else.
This can lead to collision and as a consequence the MSI IOVA addr
range is never reserved.

Fix this by passing PCI MSI IOVA address via dts property
"arm,smmu-pci-msi-iova-data". Likewise this property can be
used to set custom MSI IOVA address length, by default it should be
set to MSI IOVA default length value i.e, 0x100000.

If this property is not found in the dtb for the given platform then
the driver falls back on the default MSI IOVA address.

Since this change allows configuration of custom MSI IOVA base
address and length, rename existing as MSI_IOVA* macros accordingly.

Signed-off-by: Shyam Saini <shyamsaini@linux.microsoft.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++-
 drivers/iommu/arm/arm-smmu/arm-smmu.c       | 10 ++++-
 drivers/iommu/virtio-iommu.c                |  6 +--
 include/linux/iommu.h                       | 45 ++++++++++++++++++++-
 4 files changed, 62 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 0e4cbb2c64d73..91e88025424f9 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -32,6 +32,8 @@
 #include "arm-smmu-v3.h"
 #include "../../dma-iommu.h"
 
+struct msi_iova_data msi_data_smmu_v3;
+
 static bool disable_msipolling;
 module_param(disable_msipolling, bool, 0444);
 MODULE_PARM_DESC(disable_msipolling,
@@ -3540,8 +3542,9 @@ static void arm_smmu_get_resv_regions(struct device *dev,
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
-	region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
-					 prot, IOMMU_RESV_SW_MSI, GFP_KERNEL);
+	region = iommu_alloc_resv_region(msi_data_smmu_v3.msi_iova_base,
+					 msi_data_smmu_v3.msi_iova_length, prot,
+					 IOMMU_RESV_SW_MSI, GFP_KERNEL);
 	if (!region)
 		return;
 
@@ -4569,6 +4572,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 	struct device *dev = &pdev->dev;
 	u32 cells;
 	int ret = -EINVAL;
+	struct msi_iova_data *msi_data_ptr = &msi_data_smmu_v3;
+
+	iommu_configure_msi_iova(dev, "arm,smmu-pci-msi-iova-data", msi_data_ptr);
 
 	if (of_property_read_u32(dev->of_node, "#iommu-cells", &cells))
 		dev_err(dev, "missing #iommu-cells property\n");
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 287f8e8d25890..b636ea302cee0 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -49,6 +49,8 @@
  */
 #define QCOM_DUMMY_VAL -1
 
+struct msi_iova_data msi_data;
+
 static int force_stage;
 module_param(force_stage, int, S_IRUGO);
 MODULE_PARM_DESC(force_stage,
@@ -1593,8 +1595,9 @@ static void arm_smmu_get_resv_regions(struct device *dev,
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
-	region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
-					 prot, IOMMU_RESV_SW_MSI, GFP_KERNEL);
+	region = iommu_alloc_resv_region(msi_data.msi_iova_base,
+					 msi_data.msi_iova_length, prot,
+					 IOMMU_RESV_SW_MSI, GFP_KERNEL);
 	if (!region)
 		return;
 
@@ -2029,6 +2032,9 @@ static int arm_smmu_device_dt_probe(struct arm_smmu_device *smmu,
 	const struct arm_smmu_match_data *data;
 	struct device *dev = smmu->dev;
 	bool legacy_binding;
+	struct msi_iova_data *msi_data_ptr = &msi_data;
+
+	iommu_configure_msi_iova(dev, "arm,smmu-pci-msi-iova-data", msi_data_ptr);
 
 	if (of_property_read_u32(dev->of_node, "#global-interrupts", global_irqs))
 		return dev_err_probe(dev, -ENODEV,
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 8c8783c8b31be..ca50dee09f352 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -958,9 +958,9 @@ static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
 	 * software-mapped region.
 	 */
 	if (!msi) {
-		msi = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
-					      prot, IOMMU_RESV_SW_MSI,
-					      GFP_KERNEL);
+		msi = iommu_alloc_resv_region(MSI_IOVA_BASE_DEFAULT,
+					      MSI_IOVA_LENGTH_DEFAULT, prot,
+					      IOMMU_RESV_SW_MSI, GFP_KERNEL);
 		if (!msi)
 			return;
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2a26d3e18b24e..412a89200f094 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -1505,8 +1505,43 @@ static inline void iommu_debugfs_setup(void) {}
 #ifdef CONFIG_IOMMU_DMA
 #include <linux/msi.h>
 
-#define MSI_IOVA_BASE		0x8000000
-#define MSI_IOVA_LENGTH		0x100000
+/* MSI_IOVA_BASE_DEFAULT address can be overridden by dts specified address */
+#define MSI_IOVA_BASE_DEFAULT		0x8000000
+#define MSI_IOVA_LENGTH_DEFAULT		0x100000
+
+struct msi_iova_data {
+	u32 msi_iova_base;
+	u32 msi_iova_length;
+};
+
+static inline void iommu_configure_msi_iova(struct device *iommu_dev,
+					    const char *msi_iova_prop,
+					    struct msi_iova_data *msi_data)
+{
+	static bool is_msi_base_set_from_dt;
+	u32 msi_data_from_dt[2];
+	int rc;
+
+	rc = of_property_read_u32_array(iommu_dev->of_node, msi_iova_prop,
+					msi_data_from_dt, 2);
+	if (!rc && !is_msi_base_set_from_dt) {
+		msi_data->msi_iova_base = msi_data_from_dt[0];
+		msi_data->msi_iova_length = msi_data_from_dt[1];
+		dev_info(iommu_dev, "setting custom MSI IOVA base to 0x%x\n",
+			 msi_data->msi_iova_base);
+		is_msi_base_set_from_dt = true;
+	} else if (is_msi_base_set_from_dt &&
+		msi_data->msi_iova_base != msi_data_from_dt[0])
+		dev_warn(iommu_dev, "custom MSI IOVA base already set to 0x%x,"
+			 " skip resetting it to 0x%x\n",
+			 msi_data->msi_iova_base, msi_data_from_dt[0]);
+	else if (!is_msi_base_set_from_dt && rc == -EINVAL) {
+		msi_data->msi_iova_base = MSI_IOVA_BASE_DEFAULT;
+		msi_data->msi_iova_length =  MSI_IOVA_LENGTH_DEFAULT;
+		dev_info(iommu_dev, "using default MSI IOVA base: 0x%x\n",
+			 msi_data->msi_iova_base);
+	}
+}
 
 int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
 
@@ -1518,6 +1553,12 @@ void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg);
 struct msi_desc;
 struct msi_msg;
 
+static inline void iommu_configure_msi_iova(struct device *iommu_dev,
+					    const char *msi_iova_prop,
+					    u32 (*msi_addr)[2])
+{
+}
+
 static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
 {
 	return -ENODEV;
-- 
2.34.1