ACPI: Make acpi_dma_configure() DMA regions aware

Current ACPI DMA configuration set-up device DMA capabilities through
kernel defaults that do not take into account platform specific DMA
configurations reported by firmware.

By leveraging the ACPI acpi_dev_get_dma_resources() API, add code
in acpi_dma_configure() to retrieve the DMA regions to correctly
set-up PCI devices DMA parameters.

Rework the ACPI IORT kernel API to make sure they can accommodate
the DMA set-up required by firmware. By making PCI devices DMA set-up
ACPI IORT specific, the kernel is shielded from unwanted regressions
that could be triggered by parsing DMA resources on arches that were
previously ignoring them (ie x86/ia64), leaving kernel behaviour
unchanged on those arches.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 42 insertions, 12 deletions

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index a3215ee671c1..606af87c425f 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -681,12 +681,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
 }
 
 /**
- * iort_set_dma_mask - Set-up dma mask for a device.
+ * iort_dma_setup() - Set-up device DMA parameters.
  *
  * @dev: device to configure
+ * @dma_addr: device DMA address result pointer
+ * @size: DMA range size result pointer
  */
-void iort_set_dma_mask(struct device *dev)
+void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
 {
+        u64 mask, dmaaddr = 0, size = 0, offset = 0;
+        int ret, msb;
+
         /*
          * Set default coherent_dma_mask to 32 bit.  Drivers are expected to
          * setup the correct supported mask.
@@ -700,6 +705,34 @@ void iort_set_dma_mask(struct device *dev)
          */
         if (!dev->dma_mask)
                 dev->dma_mask = &dev->coherent_dma_mask;
+
+        size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+
+        if (dev_is_pci(dev)) {
+                ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
+                if (!ret) {
+                        msb = fls64(dmaaddr + size - 1);
+                        /*
+                         * Round-up to the power-of-two mask or set
+                         * the mask to the whole 64-bit address space
+                         * in case the DMA region covers the full
+                         * memory window.
+                         */
+                        mask = msb == 64 ? U64_MAX : (1ULL << msb) - 1;
+                        /*
+                         * Limit coherent and dma mask based on size
+                         * retrieved from firmware.
+                         */
+                        dev->coherent_dma_mask = mask;
+                        *dev->dma_mask = mask;
+                }
+        }
+
+        *dma_addr = dmaaddr;
+        *dma_size = size;
+
+        dev->dma_pfn_offset = PFN_DOWN(offset);
+        dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
 }
 
 /**
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 94500d99f2d6..0483d36433ac 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1446,20 +1446,16 @@ int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
 int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
 {
         const struct iommu_ops *iommu;
-        u64 size;
+        u64 dma_addr = 0, size = 0;
 
-        iort_set_dma_mask(dev);
+        iort_dma_setup(dev, &dma_addr, &size);
 
         iommu = iort_iommu_configure(dev);
         if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER)
                 return -EPROBE_DEFER;
 
-        size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
-        /*
-         * Assume dma valid range starts at 0 and covers the whole
-         * coherent_dma_mask.
-         */
-        arch_setup_dma_ops(dev, 0, size, iommu, attr == DEV_DMA_COHERENT);
+        arch_setup_dma_ops(dev, dma_addr, size,
+                                iommu, attr == DEV_DMA_COHERENT);
 
         return 0;
 }
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 8379d406ad2e..8d3f0bf80379 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -36,7 +36,7 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
 void acpi_configure_pmsi_domain(struct device *dev);
 int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);
 /* IOMMU interface */
-void iort_set_dma_mask(struct device *dev);
+void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);
 const struct iommu_ops *iort_iommu_configure(struct device *dev);
 #else
 static inline void acpi_iort_init(void) { }
@@ -47,7 +47,8 @@ static inline struct irq_domain *iort_get_device_domain(struct device *dev,
 { return NULL; }
 static inline void acpi_configure_pmsi_domain(struct device *dev) { }
 /* IOMMU interface */
-static inline void iort_set_dma_mask(struct device *dev) { }
+static inline void iort_dma_setup(struct device *dev, u64 *dma_addr,
+                                  u64 *size) { }
 static inline
 const struct iommu_ops *iort_iommu_configure(struct device *dev)
 { return NULL; }