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/*
* 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_stall_root_raw; \
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_unstall_root_raw; \
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_5xx.c
* Using the dma related functions are recommended for transfering 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; \
)
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