| 1 | /** |
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| 2 | * \file io.h |
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| 3 | * \date 5 September 2012 |
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| 4 | * \author Cesar Fuguet |
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| 5 | * |
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| 6 | * Utility functions to write or read memory mapped hardware registers |
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| 7 | */ |
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| 8 | #ifndef IO_H |
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| 9 | #define IO_H |
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| 10 | |
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| 11 | #include <cpu.h> |
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| 12 | |
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| 13 | /** |
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| 14 | * \brief Read an 32 bits memory mapped hardware register |
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| 15 | * |
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| 16 | * \note interrupts should be disabled while executing this function |
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| 17 | */ |
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| 18 | static inline unsigned int ioread32(uint64_t paddr) |
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| 19 | { |
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| 20 | uint32_t value; |
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| 21 | uint32_t msb = paddr >> CLUSTER_OFFSET_BITS; |
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| 22 | uint32_t lsb = paddr & ((1ULL << CLUSTER_OFFSET_BITS)-1); |
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| 23 | |
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| 24 | asm volatile("mfc2 $8, $24 \n" /* t0 <= DATA_PADDR_EXT */ |
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| 25 | "mtc2 %2, $24 \n" /* DATA_PADDR_EXT <= msb */ |
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| 26 | "lw %0, 0(%1) \n" /* value <= *paddr */ |
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| 27 | "mtc2 $8, $24 \n" /* DATA_PADDR_EXT <= 0 */ |
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| 28 | : "=r"(value) |
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| 29 | : "r"(lsb), "r"(msb) |
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| 30 | : "$8", "memory"); |
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| 31 | |
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| 32 | return value; |
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| 33 | } |
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| 34 | |
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| 35 | /** |
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| 36 | * \brief Write an 32 bits memory mapped hardware register |
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| 37 | * |
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| 38 | * \note interrupts should be disabled while executing this function |
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| 39 | */ |
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| 40 | static inline void iowrite32(uint64_t paddr, uint32_t value) |
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| 41 | { |
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| 42 | uint32_t msb = paddr >> CLUSTER_OFFSET_BITS; |
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| 43 | uint32_t lsb = paddr & ((1ULL << CLUSTER_OFFSET_BITS)-1); |
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| 44 | |
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| 45 | asm volatile("mfc2 $8, $24 \n" /* t0 <= DATA_PADDR_EXT */ |
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| 46 | "mtc2 %2, $24 \n" /* DATA_PADDR_EXT <= msb */ |
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| 47 | "sw %0, 0(%1) \n" /* value <= *paddr */ |
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| 48 | "mtc2 $8, $24 \n" /* DATA_PADDR_EXT <= 0 */ |
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| 49 | "sync \n" |
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| 50 | : /* no outputs */ |
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| 51 | : "r"(value), "r"(lsb), "r"(msb) |
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| 52 | : "$8", "memory"); |
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| 53 | } |
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| 54 | |
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| 55 | #endif |
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| 56 | |
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| 57 | /* |
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| 58 | * vim: tabstop=4 : softtabstop=4 : shiftwidth=4 : expandtab |
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| 59 | */ |
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