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Subject[PATCH v2 4/5] ACPI: Make acpi_dma_configure() DMA regions aware
Date
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>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
---
drivers/acpi/arm64/iort.c | 30 ++++++++++++++++++++++++++++--
drivers/acpi/scan.c | 12 ++++--------
include/linux/acpi_iort.h | 5 +++--
3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index a3215ee..67b85ae 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;
+
/*
* Set default coherent_dma_mask to 32 bit. Drivers are expected to
* setup the correct supported mask.
@@ -700,6 +705,27 @@ 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) {
+ mask = __roundup_pow_of_two(dmaaddr + size) - 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 dcf5f22..ae3d580 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1445,20 +1445,16 @@ 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 8379d40..8d3f0bf 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; }
--
2.10.0
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