c88dae574c
Until now, any attempts to call printk prior to early serial init has caused page faults due to the device not being mapped yet. Add static variable to track the pre-init status, and instead of page faulting just suppress the characters and log a warning right after init to give an indication that output characters have been lost. Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
118 lines
3.4 KiB
C
118 lines
3.4 KiB
C
/*
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* Copyright (c) 2020 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <kernel.h>
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#include <sys/device_mmio.h>
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#include <sys/util.h>
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#include <drivers/pcie/pcie.h>
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#include <soc.h>
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#ifdef UART_NS16550_ACCESS_IOPORT
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/* Legacy I/O Port Access to a NS16550 UART */
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#define IN(reg) sys_in8(reg + UART_NS16550_ACCESS_IOPORT)
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#define OUT(reg, val) sys_out8(val, reg + UART_NS16550_ACCESS_IOPORT)
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#elif defined(X86_SOC_EARLY_SERIAL_PCIDEV)
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/* "Modern" mapping of a UART into a PCI MMIO device. The registers
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* are still bytes, but spaced at a 32 bit stride instead of packed
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* together.
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*/
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static mm_reg_t mmio;
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#define IN(reg) (sys_read32(mmio + reg * 4) & 0xff)
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#define OUT(reg, val) sys_write32((val) & 0xff, mmio + reg * 4)
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#elif defined(X86_SOC_EARLY_SERIAL_MMIO8_ADDR)
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/* Still other devices use a MMIO region containing packed byte
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* registers
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*/
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#ifdef DEVICE_MMIO_IS_IN_RAM
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static mm_reg_t mmio;
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#define BASE mmio
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#else
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#define BASE X86_SOC_EARLY_SERIAL_MMIO8_ADDR
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#endif /* DEVICE_MMIO_IS_IN_RAM */
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#define IN(reg) sys_read8(BASE + reg)
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#define OUT(reg, val) sys_write8(val, BASE + reg)
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#else
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#error "Unsupported configuration"
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#endif
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#define REG_THR 0x00 /* Transmitter holding reg. */
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#define REG_IER 0x01 /* Interrupt enable reg. */
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#define REG_FCR 0x02 /* FIFO control reg. */
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#define REG_LCR 0x03 /* Line control reg. */
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#define REG_MCR 0x04 /* Modem control reg. */
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#define REG_LSR 0x05 /* Line status reg. */
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#define REG_BRDL 0x00 /* Baud rate divisor (LSB) */
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#define REG_BRDH 0x01 /* Baud rate divisor (MSB) */
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#define IER_DISABLE 0x00
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#define LCR_8N1 (BIT(0) | BIT(1))
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#define LCR_DLAB_SELECT BIT(7)
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#define MCR_DTR BIT(0)
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#define MCR_RTS BIT(1)
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#define LSR_THRE BIT(5)
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#define FCR_FIFO BIT(0) /* enable XMIT and RCVR FIFO */
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#define FCR_RCVRCLR BIT(1) /* clear RCVR FIFO */
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#define FCR_XMITCLR BIT(2) /* clear XMIT FIFO */
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#define FCR_FIFO_1 0 /* 1 byte in RCVR FIFO */
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static bool early_serial_init_done;
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static uint32_t suppressed_chars;
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static void serout(int c)
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{
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while ((IN(REG_LSR) & LSR_THRE) == 0) {
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}
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OUT(REG_THR, c);
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}
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int arch_printk_char_out(int c)
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{
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if (!early_serial_init_done) {
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suppressed_chars++;
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return c;
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}
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if (c == '\n') {
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serout('\r');
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}
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serout(c);
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return c;
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}
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void z_x86_early_serial_init(void)
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{
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#if defined(DEVICE_MMIO_IS_IN_RAM) && !defined(UART_NS16550_ACCESS_IOPORT)
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#ifdef X86_SOC_EARLY_SERIAL_PCIDEV
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struct pcie_mbar mbar;
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pcie_get_mbar(X86_SOC_EARLY_SERIAL_PCIDEV, 0, &mbar);
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pcie_set_cmd(X86_SOC_EARLY_SERIAL_PCIDEV, PCIE_CONF_CMDSTAT_MEM, true);
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device_map(&mmio, mbar.phys_addr, mbar.size, K_MEM_CACHE_NONE);
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#else
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device_map(&mmio, X86_SOC_EARLY_SERIAL_MMIO8_ADDR, 0x1000, K_MEM_CACHE_NONE);
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#endif
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#endif /* DEVICE_MMIO_IS_IN_RAM */
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OUT(REG_IER, IER_DISABLE); /* Disable interrupts */
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OUT(REG_LCR, LCR_DLAB_SELECT); /* DLAB select */
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OUT(REG_BRDL, 1); /* Baud divisor = 1 */
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OUT(REG_BRDH, 0);
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OUT(REG_LCR, LCR_8N1); /* LCR = 8n1 + DLAB off */
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OUT(REG_MCR, MCR_DTR | MCR_RTS);
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/* Turn on FIFO. Some hardware needs this before transmitting */
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OUT(REG_FCR, FCR_FIFO | FCR_FIFO_1 | FCR_RCVRCLR | FCR_XMITCLR);
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early_serial_init_done = true;
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if (suppressed_chars) {
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printk("WARNING: %u chars lost before early serial init\n",
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suppressed_chars);
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}
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}
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