| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de> |
| */ |
| |
| #include <linux/linkage.h> |
| #include <asm/assembler.h> |
| |
| /* |
| * r8 = bit 0-15: tx offset, bit 16-31: tx buffer size |
| * r9 = bit 0-15: rx offset, bit 16-31: rx buffer size |
| */ |
| |
| #define SSI_STX0 0x00 |
| #define SSI_SRX0 0x08 |
| #define SSI_SISR 0x14 |
| #define SSI_SIER 0x18 |
| #define SSI_SACNT 0x38 |
| |
| #define SSI_SACNT_AC97EN (1 << 0) |
| |
| #define SSI_SIER_TFE0_EN (1 << 0) |
| #define SSI_SISR_TFE0 (1 << 0) |
| #define SSI_SISR_RFF0 (1 << 2) |
| #define SSI_SIER_RFF0_EN (1 << 2) |
| |
| .text |
| .global imx_ssi_fiq_start |
| .global imx_ssi_fiq_end |
| .global imx_ssi_fiq_base |
| .global imx_ssi_fiq_rx_buffer |
| .global imx_ssi_fiq_tx_buffer |
| |
| /* |
| * imx_ssi_fiq_start is _intentionally_ not marked as a function symbol |
| * using ENDPROC(). imx_ssi_fiq_start and imx_ssi_fiq_end are used to |
| * mark the function body so that it can be copied to the FIQ vector in |
| * the vectors page. imx_ssi_fiq_start should only be called as the result |
| * of an FIQ: calling it directly will not work. |
| */ |
| imx_ssi_fiq_start: |
| ldr r12, .L_imx_ssi_fiq_base |
| |
| /* TX */ |
| ldr r13, .L_imx_ssi_fiq_tx_buffer |
| |
| /* shall we send? */ |
| ldr r11, [r12, #SSI_SIER] |
| tst r11, #SSI_SIER_TFE0_EN |
| beq 1f |
| |
| /* TX FIFO empty? */ |
| ldr r11, [r12, #SSI_SISR] |
| tst r11, #SSI_SISR_TFE0 |
| beq 1f |
| |
| mov r10, #0x10000 |
| sub r10, #1 |
| and r10, r10, r8 /* r10: current buffer offset */ |
| |
| add r13, r13, r10 |
| |
| ldrh r11, [r13] |
| strh r11, [r12, #SSI_STX0] |
| |
| ldrh r11, [r13, #2] |
| strh r11, [r12, #SSI_STX0] |
| |
| ldrh r11, [r13, #4] |
| strh r11, [r12, #SSI_STX0] |
| |
| ldrh r11, [r13, #6] |
| strh r11, [r12, #SSI_STX0] |
| |
| add r10, #8 |
| lsr r11, r8, #16 /* r11: buffer size */ |
| cmp r10, r11 |
| lslgt r8, r11, #16 |
| addle r8, #8 |
| 1: |
| /* RX */ |
| |
| /* shall we receive? */ |
| ldr r11, [r12, #SSI_SIER] |
| tst r11, #SSI_SIER_RFF0_EN |
| beq 1f |
| |
| /* RX FIFO full? */ |
| ldr r11, [r12, #SSI_SISR] |
| tst r11, #SSI_SISR_RFF0 |
| beq 1f |
| |
| ldr r13, .L_imx_ssi_fiq_rx_buffer |
| |
| mov r10, #0x10000 |
| sub r10, #1 |
| and r10, r10, r9 /* r10: current buffer offset */ |
| |
| add r13, r13, r10 |
| |
| ldr r11, [r12, #SSI_SACNT] |
| tst r11, #SSI_SACNT_AC97EN |
| |
| ldr r11, [r12, #SSI_SRX0] |
| strh r11, [r13] |
| |
| ldr r11, [r12, #SSI_SRX0] |
| strh r11, [r13, #2] |
| |
| /* dummy read to skip slot 12 */ |
| ldrne r11, [r12, #SSI_SRX0] |
| |
| ldr r11, [r12, #SSI_SRX0] |
| strh r11, [r13, #4] |
| |
| ldr r11, [r12, #SSI_SRX0] |
| strh r11, [r13, #6] |
| |
| /* dummy read to skip slot 12 */ |
| ldrne r11, [r12, #SSI_SRX0] |
| |
| add r10, #8 |
| lsr r11, r9, #16 /* r11: buffer size */ |
| cmp r10, r11 |
| lslgt r9, r11, #16 |
| addle r9, #8 |
| |
| 1: |
| @ return from FIQ |
| subs pc, lr, #4 |
| |
| .align |
| .L_imx_ssi_fiq_base: |
| imx_ssi_fiq_base: |
| .word 0x0 |
| .L_imx_ssi_fiq_rx_buffer: |
| imx_ssi_fiq_rx_buffer: |
| .word 0x0 |
| .L_imx_ssi_fiq_tx_buffer: |
| imx_ssi_fiq_tx_buffer: |
| .word 0x0 |
| .L_imx_ssi_fiq_end: |
| imx_ssi_fiq_end: |
| |
