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Subject[PATCH v2 09/14] device core: Add ability to handle multiple dma offsets
Date
The new field in struct device 'dma_pfn_offset_map' is used to facilitate
the use of multiple pfn offsets between cpu addrs and dma addrs. It is
similar to 'dma_pfn_offset' except that the offset chosen depends on the
cpu or dma address involved.

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
---
drivers/of/address.c | 65 +++++++++++++++++++++++++++++++++++--
drivers/usb/core/message.c | 3 ++
drivers/usb/core/usb.c | 3 ++
include/linux/device.h | 10 +++++-
include/linux/dma-direct.h | 10 ++++--
include/linux/dma-mapping.h | 46 ++++++++++++++++++++++++++
kernel/dma/Kconfig | 13 ++++++++
7 files changed, 144 insertions(+), 6 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 96d8cfb14a60..a01afffcde7d 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -918,6 +918,47 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
}
EXPORT_SYMBOL(of_io_request_and_map);

+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+static int attach_dma_pfn_offset_map(struct device *dev,
+ struct device_node *node, int num_ranges)
+{
+ struct of_range_parser parser;
+ struct of_range range;
+ size_t r_size = (num_ranges + 1)
+ * sizeof(struct dma_pfn_offset_region);
+ struct dma_pfn_offset_region *r;
+
+ r = devm_kzalloc(dev, r_size, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+ dev->dma_pfn_offset_map = r;
+ of_dma_range_parser_init(&parser, node);
+
+ /*
+ * Record all info for DMA ranges array. We could
+ * just use the of_range struct, but if we did that it
+ * would require more calculations for phys_to_dma and
+ * dma_to_phys conversions.
+ */
+ for_each_of_range(&parser, &range) {
+ r->cpu_beg = range.cpu_addr;
+ r->cpu_end = r->cpu_beg + range.size;
+ r->dma_beg = range.bus_addr;
+ r->dma_end = r->dma_beg + range.size;
+ r->pfn_offset = PFN_DOWN(range.cpu_addr)
+ - PFN_DOWN(range.bus_addr);
+ r++;
+ }
+ return 0;
+}
+#else
+static int attach_dma_pfn_offset_map(struct device *dev,
+ struct device_node *node, int num_ranges)
+{
+ return 0;
+}
+#endif
+
/**
* of_dma_get_range - Get DMA range info
* @dev: device pointer; only needed for a corner case.
@@ -947,6 +988,8 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
struct of_range_parser parser;
struct of_range range;
u64 dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
+ bool dma_multi_pfn_offset = false;
+ int num_ranges = 0;

while (node) {
ranges = of_get_property(node, "dma-ranges", &len);
@@ -977,10 +1020,19 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
range.bus_addr, range.cpu_addr, range.size);

+ num_ranges++;
if (dma_offset && range.cpu_addr - range.bus_addr != dma_offset) {
- pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);
- /* Don't error out as we'd break some existing DTs */
- continue;
+ if (!IS_ENABLED(CONFIG_DMA_PFN_OFFSET_MAP)) {
+ pr_warn("Can't handle multiple dma-ranges with different offsets on node(%pOF)\n", node);
+ pr_warn("Perhaps set DMA_PFN_OFFSET_MAP=y?\n");
+ /*
+ * Don't error out as we'd break some existing
+ * DTs that are using configs w/o
+ * CONFIG_DMA_PFN_OFFSET_MAP set.
+ */
+ continue;
+ }
+ dma_multi_pfn_offset = true;
}
dma_offset = range.cpu_addr - range.bus_addr;

@@ -991,6 +1043,13 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
dma_end = range.bus_addr + range.size;
}

+ if (dma_multi_pfn_offset) {
+ dma_offset = 0;
+ ret = attach_dma_pfn_offset_map(dev, node, num_ranges);
+ if (ret)
+ return ret;
+ }
+
if (dma_start >= dma_end) {
ret = -EINVAL;
pr_debug("Invalid DMA ranges configuration on node(%pOF)\n",
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 6197938dcc2d..aaa3e58f5eb4 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1960,6 +1960,9 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
*/
intf->dev.dma_mask = dev->dev.dma_mask;
intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset;
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+ intf->dev.dma_pfn_offset_map = dev->dev.dma_pfn_offset_map;
+#endif
INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
intf->minor = -1;
device_initialize(&intf->dev);
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index f16c26dc079d..d2ed4d90e56e 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -612,6 +612,9 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
*/
dev->dev.dma_mask = bus->sysdev->dma_mask;
dev->dev.dma_pfn_offset = bus->sysdev->dma_pfn_offset;
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+ dev->dev.dma_pfn_offset_map = bus->sysdev->dma_pfn_offset_map;
+#endif
set_dev_node(&dev->dev, dev_to_node(bus->sysdev));
dev->state = USB_STATE_ATTACHED;
dev->lpm_disable_count = 1;
diff --git a/include/linux/device.h b/include/linux/device.h
index ac8e37cd716a..67a240ad4fc5 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -493,6 +493,8 @@ struct dev_links_info {
* @bus_dma_limit: Limit of an upstream bridge or bus which imposes a smaller
* DMA limit than the device itself supports.
* @dma_pfn_offset: offset of DMA memory range relatively of RAM
+ * @dma_pfn_offset_map: Like dma_pfn_offset but used when there are multiple
+ * pfn offsets for multiple dma-ranges.
* @dma_parms: A low level driver may set these to teach IOMMU code about
* segment limitations.
* @dma_pools: Dma pools (if dma'ble device).
@@ -578,7 +580,13 @@ struct device {
allocations such descriptors. */
u64 bus_dma_limit; /* upstream dma constraint */
unsigned long dma_pfn_offset;
-
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+ const struct dma_pfn_offset_region *dma_pfn_offset_map;
+ /* Like dma_pfn_offset, but for
+ * the unlikely case of multiple
+ * offsets. If non-null, dma_pfn_offset
+ * will be set to 0. */
+#endif
struct device_dma_parameters *dma_parms;

struct list_head dma_pools; /* dma pools (if dma'ble) */
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 24b8684aa21d..03110a57eabc 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -14,15 +14,21 @@ extern unsigned int zone_dma_bits;
static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
{
dma_addr_t dev_addr = (dma_addr_t)paddr;
+ /* The compiler should remove the 2nd term if !DMA_PFN_OFFSET_MAP */
+ unsigned long dma_pfn_offset = dev->dma_pfn_offset
+ + dma_pfn_offset_from_phys_addr(dev, paddr);

- return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
+ return dev_addr - ((dma_addr_t)dma_pfn_offset << PAGE_SHIFT);
}

static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
{
phys_addr_t paddr = (phys_addr_t)dev_addr;
+ /* The compiler should remove the 2nd term if !DMA_PFN_OFFSET_MAP */
+ unsigned long dma_pfn_offset = dev->dma_pfn_offset
+ + dma_pfn_offset_from_dma_addr(dev, paddr);

- return paddr + ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
+ return paddr + ((phys_addr_t)dma_pfn_offset << PAGE_SHIFT);
}
#endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 330ad58fbf4d..91940bba2229 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -256,6 +256,52 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
size_t dma_direct_max_mapping_size(struct device *dev);

#ifdef CONFIG_HAS_DMA
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+struct dma_pfn_offset_region {
+ phys_addr_t cpu_beg;
+ phys_addr_t cpu_end;
+ dma_addr_t dma_beg;
+ dma_addr_t dma_end;
+ unsigned long pfn_offset;
+};
+
+static inline unsigned long dma_pfn_offset_from_dma_addr(struct device *dev,
+ dma_addr_t dma_addr)
+{
+ const struct dma_pfn_offset_region *m = dev->dma_pfn_offset_map;
+
+ if (m)
+ for (; m->cpu_end; m++)
+ if (dma_addr >= m->dma_beg && dma_addr < m->dma_end)
+ return m->pfn_offset;
+ return 0;
+}
+
+static inline unsigned long dma_pfn_offset_from_phys_addr(struct device *dev,
+ phys_addr_t paddr)
+{
+ const struct dma_pfn_offset_region *m = dev->dma_pfn_offset_map;
+
+ if (m)
+ for (; m->cpu_end; m++)
+ if (paddr >= m->cpu_beg && paddr < m->cpu_end)
+ return m->pfn_offset;
+ return 0;
+}
+#else /* CONFIG_DMA_PFN_OFFSET_MAP */
+static inline unsigned long dma_pfn_offset_from_dma_addr(struct device *dev,
+ dma_addr_t dma_addr)
+{
+ return 0;
+}
+
+static inline unsigned long dma_pfn_offset_from_phys_addr(struct device *dev,
+ phys_addr_t paddr)
+{
+ return 0;
+}
+#endif /* CONFIG_DMA_PFN_OFFSET_MAP */
+
#include <asm/dma-mapping.h>

static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 4c103a24e380..ceb7e5e8f501 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -195,3 +195,16 @@ config DMA_API_DEBUG_SG
is technically out-of-spec.

If unsure, say N.
+
+config DMA_PFN_OFFSET_MAP
+ bool "Uses a DMA range map to calculate PFN offset"
+ depends on PCIE_BRCMSTB
+ default n
+ help
+ Some devices have a dma-range that gets converted to
+ a dev->dma_pfn_offset value. This option is for the
+ atypical case of there being multiple dma-ranges requiring
+ multiple pfn offsets, which are selected from when
+ converting to phys to dma and vice versa.
+
+ If unsure, say N.
--
2.17.1
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