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/* SPDX-License-Identifier: GPL-2.0-only */
#include <stdint.h>
#include <console/console.h>
#include <device/smbus_host.h>
#include <amdblocks/acpimmio.h>
#include <amdblocks/smbus.h>
#include <soc/southbridge.h>
/*
* Between 1-10 seconds, We should never timeout normally
* Longer than this is just painful when a timeout condition occurs.
*/
#define SMBUS_TIMEOUT (100 * 1000 * 10)
/* FIXME: Passing host base for SMBUS is not long-term solution.
It is possible to have multiple buses behind same host. */
static u8 controller_read8(const uintptr_t base, const u8 reg)
{
return read8((void *)(base + reg));
}
static void controller_write8(const uintptr_t base, const u8 reg, const u8 val)
{
write8((void *)(base + reg), val);
}
static int smbus_wait_until_ready(uintptr_t mmio)
{
if ((mmio != (uintptr_t)acpimmio_smbus) &&
(mmio != (uintptr_t)acpimmio_asf)) {
printk(BIOS_ERR, "Invalid SMBus or ASF base %#zx\n", mmio);
return -1;
}
u32 loops;
loops = SMBUS_TIMEOUT;
do {
u8 val;
val = controller_read8(mmio, SMBHSTSTAT);
val &= SMBHST_STAT_VAL_BITS;
if (val == 0) { /* ready now */
return 0;
}
controller_write8(mmio, SMBHSTSTAT, val);
} while (--loops);
return -2; /* time out */
}
static int smbus_wait_until_done(uintptr_t mmio)
{
u32 loops;
loops = SMBUS_TIMEOUT;
do {
u8 val;
val = controller_read8(mmio, SMBHSTSTAT);
val &= SMBHST_STAT_VAL_BITS; /* mask off reserved bits */
if (val & SMBHST_STAT_ERROR_BITS)
return -5; /* error */
/* check IRQ status bit to see if the last host command is completed */
if (val == SMBHST_STAT_INTERRUPT) {
controller_write8(mmio, SMBHSTSTAT, val); /* clr sts */
return 0;
}
} while (--loops);
return -3; /* timeout */
}
int do_smbus_recv_byte(uintptr_t mmio, u8 device)
{
u8 byte;
if (smbus_wait_until_ready(mmio) < 0)
return -2; /* not ready */
/* set the device I'm talking to */
controller_write8(mmio, SMBHSTADDR, ((device & 0x7f) << 1) | 1);
byte = controller_read8(mmio, SMBHSTCTRL);
byte &= ~SMBHST_CTRL_MODE_BITS; /* Clear [4:2] */
byte |= SMBHST_CTRL_STRT | SMBHST_CTRL_BTE_RW; /* set mode, start */
controller_write8(mmio, SMBHSTCTRL, byte);
/* poll for transaction completion */
if (smbus_wait_until_done(mmio) < 0)
return -3; /* timeout or error */
/* read results of transaction */
byte = controller_read8(mmio, SMBHSTDAT0);
return byte;
}
int do_smbus_send_byte(uintptr_t mmio, u8 device, u8 val)
{
u8 byte;
if (smbus_wait_until_ready(mmio) < 0)
return -2; /* not ready */
/* set the command... */
controller_write8(mmio, SMBHSTDAT0, val);
/* set the device I'm talking to */
controller_write8(mmio, SMBHSTADDR, ((device & 0x7f) << 1) | 0);
byte = controller_read8(mmio, SMBHSTCTRL);
byte &= ~SMBHST_CTRL_MODE_BITS; /* Clear [4:2] */
byte |= SMBHST_CTRL_STRT | SMBHST_CTRL_BTE_RW; /* set mode, start */
controller_write8(mmio, SMBHSTCTRL, byte);
/* poll for transaction completion */
if (smbus_wait_until_done(mmio) < 0)
return -3; /* timeout or error */
return 0;
}
int do_smbus_read_byte(uintptr_t mmio, u8 device, u8 address)
{
u8 byte;
if (smbus_wait_until_ready(mmio) < 0)
return -2; /* not ready */
/* set the command/address... */
controller_write8(mmio, SMBHSTCMD, address & 0xff);
/* set the device I'm talking to */
controller_write8(mmio, SMBHSTADDR, ((device & 0x7f) << 1) | 1);
byte = controller_read8(mmio, SMBHSTCTRL);
byte &= ~SMBHST_CTRL_MODE_BITS; /* Clear [4:2] */
byte |= SMBHST_CTRL_STRT | SMBHST_CTRL_BDT_RW; /* set mode, start */
controller_write8(mmio, SMBHSTCTRL, byte);
/* poll for transaction completion */
if (smbus_wait_until_done(mmio) < 0)
return -3; /* timeout or error */
/* read results of transaction */
byte = controller_read8(mmio, SMBHSTDAT0);
return byte;
}
int do_smbus_write_byte(uintptr_t mmio, u8 device, u8 address, u8 val)
{
u8 byte;
if (smbus_wait_until_ready(mmio) < 0)
return -2; /* not ready */
/* set the command/address... */
controller_write8(mmio, SMBHSTCMD, address & 0xff);
/* set the device I'm talking to */
controller_write8(mmio, SMBHSTADDR, ((device & 0x7f) << 1) | 0);
/* output value */
controller_write8(mmio, SMBHSTDAT0, val);
byte = controller_read8(mmio, SMBHSTCTRL);
byte &= ~SMBHST_CTRL_MODE_BITS; /* Clear [4:2] */
byte |= SMBHST_CTRL_STRT | SMBHST_CTRL_BDT_RW; /* set mode, start */
controller_write8(mmio, SMBHSTCTRL, byte);
/* poll for transaction completion */
if (smbus_wait_until_done(mmio) < 0)
return -3; /* timeout or error */
return 0;
}
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