ppide: Make the N8VEM/Retrobrew file shareable and also fix some bugs

diff --git a/Kernel/dev/ppide_rbc.c b/Kernel/dev/ppide_rbc.c
new file mode 100644 (file)
index 0000000..bbe83b6
--- /dev/null
+++ b/Kernel/dev/ppide_rbc.c
@@ -0,0 +1,124 @@
+/* 2015-04-24 WRS: devide glue functions for PPIDE
+   This may need to change for some more unusual platforms but for Z80 based
+   Retrobrew / N8VEM systems should work as is */
+
+#include <kernel.h>
+#include <kdata.h>
+#include <printf.h>
+#include <stdbool.h>
+#include <timer.h>
+#include <devide.h>
+#include <blkdev.h>
+
+__sfr __at (PPIDE_BASE + 0x00) ppi_port_a;   /* IDE bus LSB */
+__sfr __at (PPIDE_BASE + 0x01) ppi_port_b;   /* IDE bus MSB */
+__sfr __at (PPIDE_BASE + 0x02) ppi_port_c;   /* IDE bus control signals */
+__sfr __at (PPIDE_BASE + 0x03) ppi_control;  /* 8255 command register */
+
+void ppide_init(void)
+{
+    ppi_control = PPIDE_PPI_BUS_READ;
+    ppi_port_c = ide_reg_status;
+}
+
+uint8_t devide_readb(uint8_t regaddr)
+{
+    uint8_t r;
+
+    /* note: ppi_control should contain PPIDE_PPI_BUS_READ already */
+    ppi_port_c = regaddr;
+    ppi_port_c = regaddr | PPIDE_RD_LINE; /* begin /RD pulse */
+    r = ppi_port_a;
+    ppi_port_c = regaddr;       /* end /RD pulse */
+    return r;
+}
+
+void devide_writeb(uint8_t regaddr, uint8_t value)
+{
+    ppi_control = PPIDE_PPI_BUS_WRITE;
+    ppi_port_c = regaddr;
+    ppi_port_a = value;
+    ppi_port_b = 0;
+    ppi_port_c = regaddr | PPIDE_WR_LINE;
+    /* FIXME: check timing */
+    ppi_port_c = regaddr;
+    ppi_control = PPIDE_PPI_BUS_READ;
+}
+
+/****************************************************************************/
+/* The innermost part of the transfer routines has to live in common memory */
+/* since it must be able to bank switch to the user memory bank.            */
+/****************************************************************************/
+COMMON_MEMORY
+
+void devide_read_data(void) __naked
+{
+    __asm
+            ld a, #ide_reg_data
+            ld c, #PPIDE_BASE+2                     ; select control lines
+            out (c), a                              ; select IDE data register
+            ld hl, (_blk_op+BLKPARAM_ADDR_OFFSET)   ; blkparam.addr
+            ld d, #ide_reg_data                     ; register address
+            ld e, #ide_reg_data | PPIDE_RD_LINE     ; register address with /RD asserted
+            ld b, #0                                ; setup count
+            ld a, (_blk_op+BLKPARAM_IS_USER_OFFSET) ; blkparam.is_user
+            or a                                    ; test is_user
+            push af                                 ; save flags
+            ld a, #PPIDE_BASE+0                     ; I will be needing this later
+            call nz, map_process_always             ; map user memory first if required
+goread:     ; now we do the transfer
+            out (c), e                              ; assert /RD
+            ld c, a                                 ; PPIDE_BASE
+            ini                                     ; read byte from LSB
+            inc c                                   ; up to MSB
+            ini                                     ; read byte from MSB
+            inc c                                   ; control lines
+            out (c), d                              ; de-assert /RD
+            inc b                                   ; (delay) counteract second ini instruction
+            jr nz, goread                           ; (delay) next word
+            ; read completed
+            pop af                                  ; recover is_user test result
+            ret z                                   ; done if kernel memory transfer
+            jp map_kernel                           ; else map kernel then return
+    __endasm;
+}
+
+void devide_write_data(void) __naked
+{
+    __asm
+            ld c, #PPIDE_BASE+2                     ; select control lines
+            ld a, #ide_reg_data
+            out (c), a                              ; select data register
+            ld a, #PPIDE_PPI_BUS_WRITE
+            inc c                                   ; up to 8255A command register
+            out (c), a                              ; 8255A ports A, B to output mode
+            dec c                                   ; back down to the control lines
+            ld hl, (_blk_op+BLKPARAM_ADDR_OFFSET)   ; blkparam.addr
+            ld d, #ide_reg_data                     ; register address
+            ld e, #ide_reg_data | PPIDE_WR_LINE     ; register address with /WR asserted
+            ld b, #0                                ; setup count
+            ld a, (_blk_op+BLKPARAM_IS_USER_OFFSET) ; blkparam.is_user
+            or a                                    ; test is_user
+            push af                                 ; save flags
+            ld a, #PPIDE_BASE+0                     ; I will be needing this later
+            call nz, map_process_always             ; map user memory first if required
+gowrite:    ; now we do the transfer
+            out (c), d                              ; de-assert /WR
+            ld c, a                                 ; PPIDE_BASE
+            outi                                    ; write byte to LSB
+            inc c                                   ; up to MSB
+            outi                                    ; write byte to MSB
+            inc c                                   ; up to control lines
+            out (c), e                              ; assert /WR
+            inc b                                   ; (delay) offset to counteract second outi instruction
+            jr nz, gowrite                          ; (delay) next word
+            ; write completed
+            out (c), d                              ; de-assert /WR
+            ld a, #PPIDE_PPI_BUS_READ
+            inc c                                   ; up to 8255A command register
+            out (c), a                              ; 8255A ports A, B to read mode
+            pop af                                  ; recover is_user test result
+            ret z                                   ; done if kernel memory transfer
+            jp map_kernel                           ; else map kernel then return
+    __endasm;
+}