zephyr/arch/x86/core/early_serial.c

121 lines
3.5 KiB
C

/*
* Copyright (c) 2020 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/kernel.h>
#include <zephyr/sys/device_mmio.h>
#include <zephyr/sys/util.h>
#include <zephyr/drivers/pcie/pcie.h>
#include <soc.h>
#define UART_IS_IOPORT_ACCESS \
DT_NODE_HAS_PROP(DT_CHOSEN(zephyr_console), io_mapped)
#if UART_IS_IOPORT_ACCESS
/* Legacy I/O Port Access to a NS16550 UART */
#define IN(reg) sys_in8(reg + DT_REG_ADDR(DT_CHOSEN(zephyr_console)))
#define OUT(reg, val) sys_out8(val, reg + DT_REG_ADDR(DT_CHOSEN(zephyr_console)))
#elif defined(X86_SOC_EARLY_SERIAL_PCIDEV)
/* "Modern" mapping of a UART into a PCI MMIO device. The registers
* are still bytes, but spaced at a 32 bit stride instead of packed
* together.
*/
static mm_reg_t mmio;
#define IN(reg) (sys_read32(mmio + reg * 4) & 0xff)
#define OUT(reg, val) sys_write32((val) & 0xff, mmio + reg * 4)
#elif defined(X86_SOC_EARLY_SERIAL_MMIO8_ADDR)
/* Still other devices use a MMIO region containing packed byte
* registers
*/
#ifdef DEVICE_MMIO_IS_IN_RAM
static mm_reg_t mmio;
#define BASE mmio
#else
#define BASE X86_SOC_EARLY_SERIAL_MMIO8_ADDR
#endif /* DEVICE_MMIO_IS_IN_RAM */
#define IN(reg) sys_read8(BASE + reg)
#define OUT(reg, val) sys_write8(val, BASE + reg)
#else
#error "Unsupported configuration"
#endif
#define REG_THR 0x00 /* Transmitter holding reg. */
#define REG_IER 0x01 /* Interrupt enable reg. */
#define REG_FCR 0x02 /* FIFO control reg. */
#define REG_LCR 0x03 /* Line control reg. */
#define REG_MCR 0x04 /* Modem control reg. */
#define REG_LSR 0x05 /* Line status reg. */
#define REG_BRDL 0x00 /* Baud rate divisor (LSB) */
#define REG_BRDH 0x01 /* Baud rate divisor (MSB) */
#define IER_DISABLE 0x00
#define LCR_8N1 (BIT(0) | BIT(1))
#define LCR_DLAB_SELECT BIT(7)
#define MCR_DTR BIT(0)
#define MCR_RTS BIT(1)
#define LSR_THRE BIT(5)
#define FCR_FIFO BIT(0) /* enable XMIT and RCVR FIFO */
#define FCR_RCVRCLR BIT(1) /* clear RCVR FIFO */
#define FCR_XMITCLR BIT(2) /* clear XMIT FIFO */
#define FCR_FIFO_1 0 /* 1 byte in RCVR FIFO */
static bool early_serial_init_done;
static uint32_t suppressed_chars;
static void serout(int c)
{
while ((IN(REG_LSR) & LSR_THRE) == 0) {
}
OUT(REG_THR, c);
}
int arch_printk_char_out(int c)
{
if (!early_serial_init_done) {
suppressed_chars++;
return c;
}
if (c == '\n') {
serout('\r');
}
serout(c);
return c;
}
void z_x86_early_serial_init(void)
{
#if defined(DEVICE_MMIO_IS_IN_RAM) && !UART_IS_IOPORT_ACCESS
#ifdef X86_SOC_EARLY_SERIAL_PCIDEV
struct pcie_bar mbar;
pcie_get_mbar(X86_SOC_EARLY_SERIAL_PCIDEV, 0, &mbar);
pcie_set_cmd(X86_SOC_EARLY_SERIAL_PCIDEV, PCIE_CONF_CMDSTAT_MEM, true);
device_map(&mmio, mbar.phys_addr, mbar.size, K_MEM_CACHE_NONE);
#else
device_map(&mmio, X86_SOC_EARLY_SERIAL_MMIO8_ADDR, 0x1000, K_MEM_CACHE_NONE);
#endif
#endif /* DEVICE_MMIO_IS_IN_RAM */
OUT(REG_IER, IER_DISABLE); /* Disable interrupts */
OUT(REG_LCR, LCR_DLAB_SELECT); /* DLAB select */
OUT(REG_BRDL, 1); /* Baud divisor = 1 */
OUT(REG_BRDH, 0);
OUT(REG_LCR, LCR_8N1); /* LCR = 8n1 + DLAB off */
OUT(REG_MCR, MCR_DTR | MCR_RTS);
/* Turn on FIFO. Some hardware needs this before transmitting */
OUT(REG_FCR, FCR_FIFO | FCR_FIFO_1 | FCR_RCVRCLR | FCR_XMITCLR);
early_serial_init_done = true;
if (suppressed_chars != 0U) {
printk("WARNING: %u chars lost before early serial init\n",
suppressed_chars);
}
}