[PATCH v2] tile: support LSI MEGARAID SAS HBA hybrid dma_ops

From: Chris Metcalf
Date: Tue Aug 06 2013 - 13:02:30 EST


The LSI MEGARAID SAS HBA suffers from the problem where it can do
64-bit DMA to streaming buffers but not to consistent buffers.
In other words, 64-bit DMA is used for disk data transfers and 32-bit
DMA must be used for control message transfers. According to LSI,
the firmware is not fully functional yet. This change implements a
kind of hybrid dma_ops to support this.

Note that on most other platforms, the 64-bit DMA addressing space is the
same as the 32-bit DMA space and they overlap the physical memory space.
No special arrangement is needed to support this kind of mixed DMA
capability. On TILE-Gx, the 64-bit DMA space is completely separate
from the 32-bit DMA space. Due to the use of the IOMMU, the 64-bit DMA
space doesn't overlap the physical memory space. On the other hand,
the 32-bit DMA space overlaps the physical memory space under 4GB.
The separate address spaces make it necessary to have separate dma_ops.

Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
---
arch/tile/include/asm/dma-mapping.h | 10 +++++++---
arch/tile/kernel/pci-dma.c | 40 ++++++++++++++++++++++++++++---------
2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/arch/tile/include/asm/dma-mapping.h b/arch/tile/include/asm/dma-mapping.h
index f2ff191..4a60059 100644
--- a/arch/tile/include/asm/dma-mapping.h
+++ b/arch/tile/include/asm/dma-mapping.h
@@ -23,6 +23,7 @@
extern struct dma_map_ops *tile_dma_map_ops;
extern struct dma_map_ops *gx_pci_dma_map_ops;
extern struct dma_map_ops *gx_legacy_pci_dma_map_ops;
+extern struct dma_map_ops *gx_hybrid_pci_dma_map_ops;

static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
@@ -44,12 +45,12 @@ static inline void set_dma_offset(struct device *dev, dma_addr_t off)

static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
- return paddr + get_dma_offset(dev);
+ return paddr;
}

static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
{
- return daddr - get_dma_offset(dev);
+ return daddr;
}

static inline void dma_mark_clean(void *addr, size_t size) {}
@@ -88,7 +89,10 @@ dma_set_mask(struct device *dev, u64 mask)
struct dma_map_ops *dma_ops = get_dma_ops(dev);

/* Handle legacy PCI devices with limited memory addressability. */
- if ((dma_ops == gx_pci_dma_map_ops) && (mask <= DMA_BIT_MASK(32))) {
+ if ((dma_ops == gx_pci_dma_map_ops ||
+ dma_ops == gx_hybrid_pci_dma_map_ops ||
+ dma_ops == gx_legacy_pci_dma_map_ops) &&
+ (mask <= DMA_BIT_MASK(32))) {
set_dma_ops(dev, gx_legacy_pci_dma_map_ops);
set_dma_offset(dev, 0);
if (mask > dev->archdata.max_direct_dma_addr)
diff --git a/arch/tile/kernel/pci-dma.c b/arch/tile/kernel/pci-dma.c
index b9fe80e..7e22e73 100644
--- a/arch/tile/kernel/pci-dma.c
+++ b/arch/tile/kernel/pci-dma.c
@@ -357,7 +357,7 @@ static void *tile_pci_dma_alloc_coherent(struct device *dev, size_t size,

addr = page_to_phys(pg);

- *dma_handle = phys_to_dma(dev, addr);
+ *dma_handle = addr + get_dma_offset(dev);

return page_address(pg);
}
@@ -387,7 +387,7 @@ static int tile_pci_dma_map_sg(struct device *dev, struct scatterlist *sglist,
sg->dma_address = sg_phys(sg);
__dma_prep_pa_range(sg->dma_address, sg->length, direction);

- sg->dma_address = phys_to_dma(dev, sg->dma_address);
+ sg->dma_address = sg->dma_address + get_dma_offset(dev);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
sg->dma_length = sg->length;
#endif
@@ -422,7 +422,7 @@ static dma_addr_t tile_pci_dma_map_page(struct device *dev, struct page *page,
BUG_ON(offset + size > PAGE_SIZE);
__dma_prep_page(page, offset, size, direction);

- return phys_to_dma(dev, page_to_pa(page) + offset);
+ return page_to_pa(page) + offset + get_dma_offset(dev);
}

static void tile_pci_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
@@ -432,7 +432,7 @@ static void tile_pci_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
{
BUG_ON(!valid_dma_direction(direction));

- dma_address = dma_to_phys(dev, dma_address);
+ dma_address -= get_dma_offset(dev);

__dma_complete_page(pfn_to_page(PFN_DOWN(dma_address)),
dma_address & PAGE_OFFSET, size, direction);
@@ -445,7 +445,7 @@ static void tile_pci_dma_sync_single_for_cpu(struct device *dev,
{
BUG_ON(!valid_dma_direction(direction));

- dma_handle = dma_to_phys(dev, dma_handle);
+ dma_handle -= get_dma_offset(dev);

__dma_complete_pa_range(dma_handle, size, direction);
}
@@ -456,7 +456,7 @@ static void tile_pci_dma_sync_single_for_device(struct device *dev,
enum dma_data_direction
direction)
{
- dma_handle = dma_to_phys(dev, dma_handle);
+ dma_handle -= get_dma_offset(dev);

__dma_prep_pa_range(dma_handle, size, direction);
}
@@ -558,21 +558,43 @@ static struct dma_map_ops pci_swiotlb_dma_ops = {
.mapping_error = swiotlb_dma_mapping_error,
};

+static struct dma_map_ops pci_hybrid_dma_ops = {
+ .alloc = tile_swiotlb_alloc_coherent,
+ .free = tile_swiotlb_free_coherent,
+ .map_page = tile_pci_dma_map_page,
+ .unmap_page = tile_pci_dma_unmap_page,
+ .map_sg = tile_pci_dma_map_sg,
+ .unmap_sg = tile_pci_dma_unmap_sg,
+ .sync_single_for_cpu = tile_pci_dma_sync_single_for_cpu,
+ .sync_single_for_device = tile_pci_dma_sync_single_for_device,
+ .sync_sg_for_cpu = tile_pci_dma_sync_sg_for_cpu,
+ .sync_sg_for_device = tile_pci_dma_sync_sg_for_device,
+ .mapping_error = tile_pci_dma_mapping_error,
+ .dma_supported = tile_pci_dma_supported
+};
+
struct dma_map_ops *gx_legacy_pci_dma_map_ops = &pci_swiotlb_dma_ops;
+struct dma_map_ops *gx_hybrid_pci_dma_map_ops = &pci_hybrid_dma_ops;
#else
struct dma_map_ops *gx_legacy_pci_dma_map_ops;
+struct dma_map_ops *gx_hybrid_pci_dma_map_ops;
#endif
EXPORT_SYMBOL(gx_legacy_pci_dma_map_ops);
+EXPORT_SYMBOL(gx_hybrid_pci_dma_map_ops);

#ifdef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
int dma_set_coherent_mask(struct device *dev, u64 mask)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);

- /* Handle legacy PCI devices with limited memory addressability. */
- if (((dma_ops == gx_pci_dma_map_ops) ||
- (dma_ops == gx_legacy_pci_dma_map_ops)) &&
+ /* Handle hybrid PCI devices with limited memory addressability. */
+ if ((dma_ops == gx_pci_dma_map_ops ||
+ dma_ops == gx_hybrid_pci_dma_map_ops ||
+ dma_ops == gx_legacy_pci_dma_map_ops) &&
(mask <= DMA_BIT_MASK(32))) {
+ if (dma_ops == gx_pci_dma_map_ops)
+ set_dma_ops(dev, gx_hybrid_pci_dma_map_ops);
+
if (mask > dev->archdata.max_direct_dma_addr)
mask = dev->archdata.max_direct_dma_addr;
}
--
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/