1/* 2 * Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9#include <linux/linkage.h> 10#include <asm/assembler.h> 11 12/* 13 * r8 = bit 0-15: tx offset, bit 16-31: tx buffer size 14 * r9 = bit 0-15: rx offset, bit 16-31: rx buffer size 15 */ 16 17#define SSI_STX0 0x00 18#define SSI_SRX0 0x08 19#define SSI_SISR 0x14 20#define SSI_SIER 0x18 21#define SSI_SACNT 0x38 22 23#define SSI_SACNT_AC97EN (1 << 0) 24 25#define SSI_SIER_TFE0_EN (1 << 0) 26#define SSI_SISR_TFE0 (1 << 0) 27#define SSI_SISR_RFF0 (1 << 2) 28#define SSI_SIER_RFF0_EN (1 << 2) 29 30 .text 31 .global imx_ssi_fiq_start 32 .global imx_ssi_fiq_end 33 .global imx_ssi_fiq_base 34 .global imx_ssi_fiq_rx_buffer 35 .global imx_ssi_fiq_tx_buffer 36 37imx_ssi_fiq_start: 38 ldr r12, imx_ssi_fiq_base 39 40 /* TX */ 41 ldr r11, imx_ssi_fiq_tx_buffer 42 43 /* shall we send? */ 44 ldr r13, [r12, #SSI_SIER] 45 tst r13, #SSI_SIER_TFE0_EN 46 beq 1f 47 48 /* TX FIFO empty? */ 49 ldr r13, [r12, #SSI_SISR] 50 tst r13, #SSI_SISR_TFE0 51 beq 1f 52 53 mov r10, #0x10000 54 sub r10, #1 55 and r10, r10, r8 /* r10: current buffer offset */ 56 57 add r11, r11, r10 58 59 ldrh r13, [r11] 60 strh r13, [r12, #SSI_STX0] 61 62 ldrh r13, [r11, #2] 63 strh r13, [r12, #SSI_STX0] 64 65 ldrh r13, [r11, #4] 66 strh r13, [r12, #SSI_STX0] 67 68 ldrh r13, [r11, #6] 69 strh r13, [r12, #SSI_STX0] 70 71 add r10, #8 72 lsr r13, r8, #16 /* r13: buffer size */ 73 cmp r10, r13 74 lslgt r8, r13, #16 75 addle r8, #8 761: 77 /* RX */ 78 79 /* shall we receive? */ 80 ldr r13, [r12, #SSI_SIER] 81 tst r13, #SSI_SIER_RFF0_EN 82 beq 1f 83 84 /* RX FIFO full? */ 85 ldr r13, [r12, #SSI_SISR] 86 tst r13, #SSI_SISR_RFF0 87 beq 1f 88 89 ldr r11, imx_ssi_fiq_rx_buffer 90 91 mov r10, #0x10000 92 sub r10, #1 93 and r10, r10, r9 /* r10: current buffer offset */ 94 95 add r11, r11, r10 96 97 ldr r13, [r12, #SSI_SACNT] 98 tst r13, #SSI_SACNT_AC97EN 99 100 ldr r13, [r12, #SSI_SRX0] 101 strh r13, [r11] 102 103 ldr r13, [r12, #SSI_SRX0] 104 strh r13, [r11, #2] 105 106 /* dummy read to skip slot 12 */ 107 ldrne r13, [r12, #SSI_SRX0] 108 109 ldr r13, [r12, #SSI_SRX0] 110 strh r13, [r11, #4] 111 112 ldr r13, [r12, #SSI_SRX0] 113 strh r13, [r11, #6] 114 115 /* dummy read to skip slot 12 */ 116 ldrne r13, [r12, #SSI_SRX0] 117 118 add r10, #8 119 lsr r13, r9, #16 /* r13: buffer size */ 120 cmp r10, r13 121 lslgt r9, r13, #16 122 addle r9, #8 123 1241: 125 @ return from FIQ 126 subs pc, lr, #4 127imx_ssi_fiq_base: 128 .word 0x0 129imx_ssi_fiq_rx_buffer: 130 .word 0x0 131imx_ssi_fiq_tx_buffer: 132 .word 0x0 133imx_ssi_fiq_end: 134