[PATCH 09/15] device core: Add ability to handle multiple dma offsets
Jim Quinlan
james.quinlan at broadcom.com
Tue May 19 20:34:07 UTC 2020
The device variable 'dma_pfn_offset' is used to do a single
linear map between cpu addrs and dma addrs. The variable
'dma_map' is added to struct device to point to an array
of multiple offsets which is required for some devices.
Signed-off-by: Jim Quinlan <james.quinlan at broadcom.com>
---
drivers/of/address.c | 50 ++++++++++++++++++++++++++++++++++---
include/linux/device.h | 9 ++++++-
include/linux/dma-mapping.h | 44 ++++++++++++++++++++++++++++++++
kernel/dma/Kconfig | 12 +++++++++
4 files changed, 111 insertions(+), 4 deletions(-)
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 96d8cfb14a60..7dfff618af6a 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -947,6 +947,8 @@ 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 +979,18 @@ 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;
+ dma_multi_pfn_offset = true;
+ if (!IS_ENABLED(CONFIG_DMA_PFN_OFFSET_MAP)) {
+ 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 that are using configs
+ * w/o CONFIG_DMA_PFN_OFFSET_MAP set.
+ */
+ continue;
+ }
}
dma_offset = range.cpu_addr - range.bus_addr;
@@ -991,6 +1001,40 @@ int of_dma_get_range(struct device *dev, struct device_node *np, u64 *dma_addr,
dma_end = range.bus_addr + range.size;
}
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+ if (dma_multi_pfn_offset) {
+ size_t r_size = (num_ranges + 1)
+ * sizeof(struct dma_pfn_offset_region);
+ struct dma_pfn_offset_region *r;
+
+ if (!dev)
+ return -EINVAL;
+
+ dma_offset = 0;
+ r = devm_kcalloc(dev, 1, r_size, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+ dev->dma_offset_map = (const void *) 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++;
+ }
+ }
+#endif
+
if (dma_start >= dma_end) {
ret = -EINVAL;
pr_debug("Invalid DMA ranges configuration on node(%pOF)\n",
diff --git a/include/linux/device.h b/include/linux/device.h
index ac8e37cd716a..6cd916860b5f 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_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 +580,12 @@ struct device {
allocations such descriptors. */
u64 bus_dma_limit; /* upstream dma constraint */
unsigned long dma_pfn_offset;
-
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+ const void *dma_offset_map; /* Like dma_pfn_offset, but for
+ * the unlikely case of multiple
+ * offsets. If non-null, dma_pfn_offset
+ * will be 0. */
+#endif
struct device_dma_parameters *dma_parms;
struct list_head dma_pools; /* dma pools (if dma'ble) */
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 330ad58fbf4d..288d8089faf7 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -256,6 +256,38 @@ 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_frm_dma_addr(const void *arr,
+ dma_addr_t dma_addr)
+{
+ const struct dma_pfn_offset_region *m;
+
+ for (m = arr; 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_frm_phys_addr(const void *arr,
+ phys_addr_t paddr)
+{
+ const struct dma_pfn_offset_region *m;
+
+ for (m = arr; m->cpu_end; m++)
+ if (paddr >= m->cpu_beg && paddr < m->cpu_end)
+ return m->pfn_offset;
+ 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)
@@ -575,6 +607,18 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
{
return 0;
}
+#ifdef CONFIG_DMA_PFN_OFFSET_MAP
+static inline unsigned long dma_pfn_offset_frm_dma_addr(const void *arr,
+ dma_addr_t dma_addr)
+{
+ return 0;
+}
+static inline unsigned long dma_pfn_offset_frm_phys_addr(const void *arr,
+ phys_addr_t paddr)
+{
+ return 0;
+}
+#endif /* CONFIG_DMA_PFN_OFFSET_MAP */
#endif /* CONFIG_HAS_DMA */
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 4c103a24e380..b4c3de521bf9 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -195,3 +195,15 @@ 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"
+ 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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