1 files changed, 147 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/ssi-fiq.S b/arch/arm/mach-imx/ssi-fiq.S
new file mode 100644
index 000000000000..a8b93c5f29b5
--- /dev/null
+++ b/arch/arm/mach-imx/ssi-fiq.S
@@ -0,0 +1,147 @@
+/*
+ *  Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#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:
+