From e079f800441ebf04d46e5e0b7187ea96df743a4d Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Fri, 30 Nov 2018 22:28:33 +0000
Subject: [PATCH] zxmmc: much like the divmmc but different ports

---
 Kernel/dev/zx/zxmmc.c | 111 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 Kernel/dev/zx/zxmmc.c

diff --git a/Kernel/dev/zx/zxmmc.c b/Kernel/dev/zx/zxmmc.c
new file mode 100644
index 00000000..2077faa9
--- /dev/null
+++ b/Kernel/dev/zx/zxmmc.c
@@ -0,0 +1,111 @@
+#include <kernel.h>
+#include <blkdev.h>
+#include <devsd.h>
+#include <devtty.h>
+
+/* FIXME: optimise by unrolling inir and otir 16 ways */
+
+__sfr __at 0x1F zxmmc_cs;
+__sfr __at 0x3F zxmmc_data;
+
+void sd_spi_raise_cs(void)
+{
+    zxmmc_cs = 0xF7;		/* Active low NMI off */
+}
+
+void sd_spi_transmit_byte(uint8_t b)
+{
+    zxmmc_data = b;
+}
+
+uint8_t sd_spi_receive_byte(void)
+{
+    return zxmmc_data;
+}
+
+void sd_spi_lower_cs(void)
+{
+    if (sd_drive == 0)
+      zxmmc_cs = 0xF6;	/* Lower bit 0 (active low) */
+    else
+      zxmmc_cs = 0xF5;	/* Lower bit 1 (active low) */
+}
+
+void sd_spi_clock(bool go_fast)
+{
+}
+
+COMMON_MEMORY
+
+/*
+ * FIXME: swap support
+ *
+ * Could also unroll these a bit for speed
+ */
+
+bool sd_spi_receive_sector(void) __naked
+{
+  __asm
+    ld a, (_blk_op+BLKPARAM_IS_USER_OFFSET)
+    ld hl, (_blk_op+BLKPARAM_ADDR_OFFSET)
+    push af
+#ifdef SWAPDEV
+    cp #2
+    jr nz, not_swapin
+    ld a,(_blk_op+BLKPARAM_SWAP_PAGE)
+    call map_for_swap
+    jr doread
+not_swapin:
+#endif
+    or a
+    call nz,map_process_always
+doread:
+    ld bc, #0x3f	 ; b = 0, c = port
+    ld a,#0x05
+    out (0xfe),a
+    inir
+    ld a,#0x02
+    out (0xfe),a
+    inir
+    ld a,(_vtborder)
+    out (0xfe),a
+    pop af
+    or a
+    jp nz,map_kernel
+    ret
+  __endasm;
+}
+
+bool sd_spi_transmit_sector(void) __naked
+{
+  __asm
+    ld a, (_blk_op+BLKPARAM_IS_USER_OFFSET)
+    ld hl, (_blk_op+BLKPARAM_ADDR_OFFSET)
+    push af
+#ifdef SWAPDEV
+    cp #2
+    jr nz, not_swapout
+    ld a, (_blk_op+BLKPARAM_SWAP_PAGE)
+    call map_for_swap
+    jr dowrite
+not_swapout:
+#endif
+    or a
+    call nz,map_process_always
+dowrite:
+    ld bc, #0x3f
+    ld a,#0x05
+    out (0xfe),a
+    otir
+    ld a,#0x02
+    out (0xfe),a
+    otir
+    ld a,(_vtborder)
+    out (0xfe),a
+    pop af
+    or a
+    jp nz,map_kernel
+    ret
+  __endasm;
+}
+
-- 
2.34.1