| Message ID | 1471435517-7840-2-git-send-email-rogerq@ti.com |
|---|---|
| State | Accepted |
| Commit | d248220f0465b818887baa9829e691fe662b2c5e |
| Headers | show |
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index d009f79..bf02dbd 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -111,7 +111,7 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) /* The ARM override for dma_max_pfn() */ static inline unsigned long dma_max_pfn(struct device *dev) { - return PHYS_PFN_OFFSET + dma_to_pfn(dev, *dev->dma_mask); + return dma_to_pfn(dev, *dev->dma_mask); } #define dma_max_pfn(dev) dma_max_pfn(dev)
Since commit 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation"), dma_to_pfn() already returns the PFN with the physical memory start offset so we don't need to add it again. This fixes USB mass storage lock-up problem on systems that can't do DMA over the entire physical memory range (e.g.) Keystone 2 systems with 4GB RAM can only do DMA over the first 2GB. [K2E-EVM]. What happens there is that without this patch SCSI layer sets a wrong bounce buffer limit in scsi_calculate_bounce_limit() for the USB mass storage device. dma_max_pfn() evaluates to 0x8fffff and bounce_limit is set to 0x8fffff000 whereas maximum DMA'ble physical memory on Keystone 2 is 0x87fffffff. This results in non DMA'ble pages being given to the USB controller and hence the lock-up. NOTE: in the above case, USB-SCSI-device's dma_pfn_offset was showing as 0. This should have really been 0x780000 as on K2e, LOWMEM_START is 0x80000000 and HIGHMEM_START is 0x800000000. DMA zone is 2GB so dma_max_pfn should be 0x87ffff. The incorrect dma_pfn_offset for the USB storage device is because USB devices are not correctly inheriting the dma_pfn_offset from the USB host controller. This will be fixed by a separate patch. Fixes: 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation") Cc: stable@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Olof Johansson <olof@lixom.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Linus Walleij <linus.walleij@linaro.org> Reported-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Roger Quadros <rogerq@ti.com> --- arch/arm/include/asm/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.7.4