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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/blackfin/lib/ins.S
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/blackfin/lib/ins.S')
-rw-r--r--arch/blackfin/lib/ins.S118
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/blackfin/lib/ins.S b/arch/blackfin/lib/ins.S
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+++ b/arch/blackfin/lib/ins.S
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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_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_5xx.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; \
+)