| /************************************************************************* |
| * Copyright ARC International (www.arc.com) 2007-2009 |
| * |
| * Vineetg: Feb 2009 |
| * -Reworked the API to work with ARC PCI Bridge |
| * |
| * vineetg: Feb 2009 |
| * -For AA4 board, kernel to DMA address APIs |
| ************************************************************************/ |
| |
| /* Some notes on DMA <=> kernel address generation |
| * |
| * A simplistic implementation will generate 0 based bus address. |
| * For e.g. 0x8AAA_0000 becomes 0x0AAA_0000 bus addr |
| * However this doesnt work with PCI devices behind the PCI Host Bridge on AA4 |
| * which can't allow 0 based addresses. So the API for special case of PCI |
| * makes corrections |
| * |
| * As a small optimisation, if PCI is not enabled we can simply return |
| * 0 based bus addr hence the CONFIG_xx check for PCI Host Bridge |
| */ |
| |
| #ifndef __BOARD_RUBY_PLAT_DMA_ADDR_H |
| #define __BOARD_RUBY_PLAT_DMA_ADDR_H |
| |
| #include <linux/device.h> |
| |
| static inline unsigned long plat_dma_addr_to_kernel(struct device *dev, dma_addr_t dma_addr) |
| { |
| return (unsigned long)bus_to_virt(dma_addr); |
| } |
| |
| static inline dma_addr_t plat_kernel_addr_to_dma(struct device *dev, void *ptr) |
| { |
| /* |
| * To Catch buggy drivers which can call DMA map API with kernel vaddr |
| * i.e. for buffers alloc via vmalloc or ioremap which are not gaurnateed |
| * to be PHY contiguous and hence unfit for DMA anyways. |
| * On ARC kernel virtual address is 0x7000_0000 to 0x7FFF_FFFF, so |
| * ideally we want to check this range here, but our implementation is |
| * better as it checks for even worse user virtual address as well. |
| */ |
| BUG_ON(ptr < (void*)PAGE_OFFSET); |
| |
| return virt_to_bus(ptr); |
| } |
| |
| #endif // #ifndef __BOARD_RUBY_PLAT_DMA_ADDR_H |
| |
