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Diffstat (limited to 'kernel/arch/blackfin/lib/ins.S')
| -rw-r--r-- | kernel/arch/blackfin/lib/ins.S | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/kernel/arch/blackfin/lib/ins.S b/kernel/arch/blackfin/lib/ins.S new file mode 100644 index 000000000..d59608dec --- /dev/null +++ b/kernel/arch/blackfin/lib/ins.S @@ -0,0 +1,118 @@ +/* + * arch/blackfin/lib/ins.S - ins{bwl} using hardware loops + * + * Copyright 2004-2008 Analog Devices Inc. + * Copyright (C) 2005 Bas Vermeulen, BuyWays BV <bas@buyways.nl> + * Licensed under the GPL-2 or later. + */ + +#include <linux/linkage.h> +#include <asm/blackfin.h> + +.align 2 + +#ifdef CONFIG_IPIPE +# define DO_CLI \ + [--sp] = rets; \ + [--sp] = (P5:0); \ + sp += -12; \ + call ___ipipe_disable_root_irqs_hw; \ + sp += 12; \ + (P5:0) = [sp++]; +# define CLI_INNER_NOP +#else +# define DO_CLI cli R3; +# define CLI_INNER_NOP nop; nop; nop; +#endif + +#ifdef CONFIG_IPIPE +# define DO_STI \ + sp += -12; \ + call ___ipipe_enable_root_irqs_hw; \ + sp += 12; \ +2: rets = [sp++]; +#else +# define DO_STI 2: sti R3; +#endif + +#ifdef CONFIG_BFIN_INS_LOWOVERHEAD +# define CLI_OUTER DO_CLI; +# define STI_OUTER DO_STI; +# define CLI_INNER 1: +# if ANOMALY_05000416 +# define STI_INNER nop; 2: nop; +# else +# define STI_INNER 2: +# endif +#else +# define CLI_OUTER +# define STI_OUTER +# define CLI_INNER 1: DO_CLI; CLI_INNER_NOP; +# define STI_INNER DO_STI; +#endif + +/* + * Reads on the Blackfin are speculative. In Blackfin terms, this means they + * can be interrupted at any time (even after they have been issued on to the + * external bus), and re-issued after the interrupt occurs. + * + * If a FIFO is sitting on the end of the read, it will see two reads, + * when the core only sees one. The FIFO receives the read which is cancelled, + * and not delivered to the core. + * + * To solve this, interrupts are turned off before reads occur to I/O space. + * There are 3 versions of all these functions + * - turns interrupts off every read (higher overhead, but lower latency) + * - turns interrupts off every loop (low overhead, but longer latency) + * - DMA version, which do not suffer from this issue. DMA versions have + * different name (prefixed by dma_ ), and are located in + * ../kernel/bfin_dma.c + * Using the dma related functions are recommended for transferring large + * buffers in/out of FIFOs. + */ + +#define COMMON_INS(func, ops) \ +ENTRY(_ins##func) \ + P0 = R0; /* P0 = port */ \ + CLI_OUTER; /* 3 instructions before first read access */ \ + P1 = R1; /* P1 = address */ \ + P2 = R2; /* P2 = count */ \ + SSYNC; \ + \ + LSETUP(1f, 2f) LC0 = P2; \ + CLI_INNER; \ + ops; \ + STI_INNER; \ + \ + STI_OUTER; \ + RTS; \ +ENDPROC(_ins##func) + +COMMON_INS(l, \ + R0 = [P0]; \ + [P1++] = R0; \ +) + +COMMON_INS(w, \ + R0 = W[P0]; \ + W[P1++] = R0; \ +) + +COMMON_INS(w_8, \ + R0 = W[P0]; \ + B[P1++] = R0; \ + R0 = R0 >> 8; \ + B[P1++] = R0; \ +) + +COMMON_INS(b, \ + R0 = B[P0]; \ + B[P1++] = R0; \ +) + +COMMON_INS(l_16, \ + R0 = [P0]; \ + W[P1++] = R0; \ + R0 = R0 >> 16; \ + W[P1++] = R0; \ +) |