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authorTaylor Hutt <thutt@chromium.org>2012-10-29 05:23:58 +0000
committerTom Rini <trini@ti.com>2012-11-02 15:20:42 -0700
commit64738e8ae89214030061f62d6598e837664916c3 (patch)
tree8196246d368f2ea24a541ef89b2f1b4344ff34ca /drivers/block
parentb4c5bbce49a081f5d05837ba13ee76afeff72d91 (diff)
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ahci: Use virt_to_phys() to denote physical addresses for DMA
Update the assignment of various physical memory buffers used by the SATA controller to explicitly be denoted as physical addresses. The memory is identity-mapped, so these function calls are a nop, but they provide good semantic documentation for any maintainers. The return value of virt_to_phys() is 'unsigned long'. On machines where sizeof(unsigned long) != sizeof(pointer), a cast through (uintptr_t) is needed to appease the compiler due to the potential of losing the upper 32 bits of the address. In compilation this scenario, a physical address could be 64-bits, yet the C pointer environment only allows 32-bit addresses; the constraint is that pointers cannot address more than 4Gb of memory and if virt_to_phys() ever returns an out-of-range value for the physical address, there are issues with emmory mapping which must be solved. However, since the memory is identify mappeed, there is no problem introducing the cast: the original pointer will reside in 32-bits, so the physical address will also be within in 32-bits. Signed-off-by: Taylor Hutt <thutt@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/ahci.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/block/ahci.c b/drivers/block/ahci.c
index 20c5336..00de086 100644
--- a/drivers/block/ahci.c
+++ b/drivers/block/ahci.c
@@ -431,25 +431,27 @@ static int ahci_port_start(u8 port)
* First item in chunk of DMA memory: 32-slot command table,
* 32 bytes each in size
*/
- pp->cmd_slot = (struct ahci_cmd_hdr *)mem;
+ pp->cmd_slot =
+ (struct ahci_cmd_hdr *)(uintptr_t)virt_to_phys((void *)mem);
debug("cmd_slot = 0x%x\n", (unsigned)pp->cmd_slot);
mem += (AHCI_CMD_SLOT_SZ + 224);
/*
* Second item: Received-FIS area
*/
- pp->rx_fis = mem;
+ pp->rx_fis = virt_to_phys((void *)mem);
mem += AHCI_RX_FIS_SZ;
/*
* Third item: data area for storing a single command
* and its scatter-gather table
*/
- pp->cmd_tbl = mem;
+ pp->cmd_tbl = virt_to_phys((void *)mem);
debug("cmd_tbl_dma = 0x%x\n", pp->cmd_tbl);
mem += AHCI_CMD_TBL_HDR;
- pp->cmd_tbl_sg = (struct ahci_sg *)mem;
+ pp->cmd_tbl_sg =
+ (struct ahci_sg *)(uintptr_t)virt_to_phys((void *)mem);
writel_with_flush((u32) pp->cmd_slot, port_mmio + PORT_LST_ADDR);