| Sascha Hauer | 8380222 | 2009-11-25 16:41:04 +0100 | [diff] [blame] | 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 | |
| 37 | imx_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 |
| 76 | 1: |
| 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 | |
| 124 | 1: |
| 125 | @ return from FIQ |
| 126 | subs pc, lr, #4 |
| 127 | imx_ssi_fiq_base: |
| 128 | .word 0x0 |
| 129 | imx_ssi_fiq_rx_buffer: |
| 130 | .word 0x0 |
| 131 | imx_ssi_fiq_tx_buffer: |
| 132 | .word 0x0 |
| 133 | imx_ssi_fiq_end: |
| 134 | |