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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
#include <arch/io.h>
#include <device/pnp.h>
#include <stdint.h>
#include "lpc47n207.h"
/*
* This code tries to discover the SMSC LPC47N207 superio chip which can be
* connected over an LPC dongle. The chip could be bootstrap mapped to one of
* four LPC addresses: 0x2e, 0x4e, 0x162e, and 0x164e.
*
* Initializing the UART requires accesses to a few control registers. This
* structure includes the register offset and the value to write (along with
* the mask).
*/
typedef struct {
u8 conf_reg;
u8 value;
u8 mask;
} uart_conf;
/* All regs/values to write to initialize the LPC47N207 UART */
static const uart_conf uart_conf_data [] = {
{2, (1 << 3), (1 << 3)}, /* cr02, enable Primary UART power */
{0xc, (1 << 6), (1 << 6)}, /* cr0c, enable Primary UART high speed */
{0x24, (CONFIG_TTYS0_BASE >> 3) << 1, 0xff}, /* cr24, base addr */
};
void try_enabling_LPC47N207_uart(void)
{
u8 reg_value;
const uart_conf* conf_item;
u16 lpc_ports[] = {0x2e, 0x4e, 0x162e, 0x164e};
u16 lpc_port;
int i, j;
#define CONF_ENABLE 0x55
#define CONF_DISABLE 0xaa
for (j = 0; j < ARRAY_SIZE(lpc_ports); j++) {
lpc_port = lpc_ports[j];
/* enable CONFIG mode */
outb(CONF_ENABLE, lpc_port);
reg_value = inb(lpc_port);
if (reg_value != CONF_ENABLE) {
continue; /* There is no LPC device at this address */
}
do {
/*
* Registers 12 and 13 hold config address, look for a
* match.
*/
outb(0x12, lpc_port);
reg_value = inb(lpc_port + 1);
if (reg_value != (lpc_port & 0xff))
break;
outb(0x13, lpc_port);
reg_value = inb(lpc_port + 1);
if (reg_value != (lpc_port >> 8))
break;
/* This must be the SMSC LPC 47N207, enable the UART. */
for (i = 0; i < ARRAY_SIZE(uart_conf_data); i++) {
u8 reg, value, mask;
conf_item = uart_conf_data + i;
reg = conf_item->conf_reg;
value = conf_item->value;
mask = conf_item->mask;
outb(reg, lpc_port);
reg_value = inb(lpc_port + 1);
reg_value &= ~mask;
reg_value |= (value & mask);
outb(reg_value, lpc_port + 1);
}
} while (0);
outb(CONF_DISABLE, lpc_port);
}
}
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