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CS423x: Clean up RAM download state machine

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This commit is contained in:
RichardG867 2025-01-18 11:06:18 -03:00
parent 351390b579
commit fb3469c74e
1 changed files with 16 additions and 10 deletions
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26
src/sound/snd_cs423x.c
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@ -51,6 +51,12 @@ enum {
CRYSTAL_CS4237B = 0xc8,
CRYSTAL_CS4238B = 0xc9
};
enum {
CRYSTAL_RAM_CMD = 0,
CRYSTAL_RAM_ADDR_LO = 1,
CRYSTAL_RAM_ADDR_HI = 2,
CRYSTAL_RAM_DATA = 3
};
enum {
CRYSTAL_SLAM_NONE = 0,
CRYSTAL_SLAM_INDEX = 1,
@ -160,7 +166,7 @@ cs423x_read(uint16_t addr, void *priv)
/* Reading RAM is undocumented, but performed by:
- Windows drivers (unknown purpose)
- Intel VS440FX BIOS (PnP ROM checksum recalculation) */
if (dev->ram_dl == 3)
if (dev->ram_dl == CRYSTAL_RAM_DATA)
ret = dev->ram_data[dev->ram_addr++];
break;
@ -255,7 +261,7 @@ cs423x_write(uint16_t addr, uint8_t val, void *priv)
case 5: /* Control/RAM Access */
switch (dev->ram_dl) {
case 0: /* commands */
case CRYSTAL_RAM_CMD: /* commands */
switch (val) {
case 0x55: /* Disable PnP Key */
dev->pnp_enable = 0;
@ -273,7 +279,7 @@ cs423x_write(uint16_t addr, uint8_t val, void *priv)
break;
case 0xaa: /* Download RAM */
dev->ram_dl = 1;
dev->ram_dl = CRYSTAL_RAM_ADDR_LO;
break;
default:
@ -281,17 +287,17 @@ cs423x_write(uint16_t addr, uint8_t val, void *priv)
}
break;
case 1: /* low address byte */
case CRYSTAL_RAM_ADDR_LO: /* low address byte */
dev->ram_addr = val;
dev->ram_dl++;
dev->ram_dl = CRYSTAL_RAM_ADDR_HI;
break;
case 2: /* high address byte */
dev->ram_addr |= (val << 8);
dev->ram_dl++;
case CRYSTAL_RAM_ADDR_HI: /* high address byte */
dev->ram_addr |= val << 8;
dev->ram_dl = CRYSTAL_RAM_DATA;
break;
case 3: /* data */
case CRYSTAL_RAM_DATA: /* data */
dev->ram_data[dev->ram_addr++] = val;
break;
@ -303,7 +309,7 @@ cs423x_write(uint16_t addr, uint8_t val, void *priv)
case 6: /* RAM Access End */
/* TriGem Delhi-III BIOS writes undocumented value 0x40 instead of 0x00. */
if ((val == 0x00) || (val == 0x40)) {
dev->ram_dl = 0;
dev->ram_dl = CRYSTAL_RAM_CMD;
/* Update PnP state and resource data. */
cs423x_pnp_enable(dev, 1, 0);