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-rw-r--r--drivers/tty/serial/earlycon.c330
1 files changed, 330 insertions, 0 deletions
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
new file mode 100644
index 0000000000..a5fbb6ed38
--- /dev/null
+++ b/drivers/tty/serial/earlycon.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@kernel.org>
+ *
+ * Based on 8250 earlycon:
+ * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
+ * Bjorn Helgaas <bjorn.helgaas@hp.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/serial_core.h>
+#include <linux/sizes.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/acpi.h>
+
+#ifdef CONFIG_FIX_EARLYCON_MEM
+#include <asm/fixmap.h>
+#endif
+
+#include <asm/serial.h>
+
+static struct console early_con = {
+ .name = "uart", /* fixed up at earlycon registration */
+ .flags = CON_PRINTBUFFER | CON_BOOT,
+ .index = 0,
+};
+
+static struct earlycon_device early_console_dev = {
+ .con = &early_con,
+};
+
+static void __iomem * __init earlycon_map(resource_size_t paddr, size_t size)
+{
+ void __iomem *base;
+#ifdef CONFIG_FIX_EARLYCON_MEM
+ set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK);
+ base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
+ base += paddr & ~PAGE_MASK;
+#else
+ base = ioremap(paddr, size);
+#endif
+ if (!base)
+ pr_err("%s: Couldn't map %pa\n", __func__, &paddr);
+
+ return base;
+}
+
+static void __init earlycon_init(struct earlycon_device *device,
+ const char *name)
+{
+ struct console *earlycon = device->con;
+ const char *s;
+ size_t len;
+
+ /* scan backwards from end of string for first non-numeral */
+ for (s = name + strlen(name);
+ s > name && s[-1] >= '0' && s[-1] <= '9';
+ s--)
+ ;
+ if (*s)
+ earlycon->index = simple_strtoul(s, NULL, 10);
+ len = s - name;
+ strscpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
+ earlycon->data = &early_console_dev;
+}
+
+static void __init earlycon_print_info(struct earlycon_device *device)
+{
+ struct console *earlycon = device->con;
+ struct uart_port *port = &device->port;
+
+ if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||
+ port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)
+ pr_info("%s%d at MMIO%s %pa (options '%s')\n",
+ earlycon->name, earlycon->index,
+ (port->iotype == UPIO_MEM) ? "" :
+ (port->iotype == UPIO_MEM16) ? "16" :
+ (port->iotype == UPIO_MEM32) ? "32" : "32be",
+ &port->mapbase, device->options);
+ else
+ pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
+ earlycon->name, earlycon->index,
+ port->iobase, device->options);
+}
+
+static int __init parse_options(struct earlycon_device *device, char *options)
+{
+ struct uart_port *port = &device->port;
+ int length;
+ resource_size_t addr;
+
+ if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
+ return -EINVAL;
+
+ switch (port->iotype) {
+ case UPIO_MEM:
+ port->mapbase = addr;
+ break;
+ case UPIO_MEM16:
+ port->regshift = 1;
+ port->mapbase = addr;
+ break;
+ case UPIO_MEM32:
+ case UPIO_MEM32BE:
+ port->regshift = 2;
+ port->mapbase = addr;
+ break;
+ case UPIO_PORT:
+ port->iobase = addr;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (options) {
+ char *uartclk;
+
+ device->baud = simple_strtoul(options, NULL, 0);
+ uartclk = strchr(options, ',');
+ if (uartclk && kstrtouint(uartclk + 1, 0, &port->uartclk) < 0)
+ pr_warn("[%s] unsupported earlycon uart clkrate option\n",
+ options);
+ length = min(strcspn(options, " ") + 1,
+ (size_t)(sizeof(device->options)));
+ strscpy(device->options, options, length);
+ }
+
+ return 0;
+}
+
+static int __init register_earlycon(char *buf, const struct earlycon_id *match)
+{
+ int err;
+ struct uart_port *port = &early_console_dev.port;
+
+ /* On parsing error, pass the options buf to the setup function */
+ if (buf && !parse_options(&early_console_dev, buf))
+ buf = NULL;
+
+ spin_lock_init(&port->lock);
+ if (!port->uartclk)
+ port->uartclk = BASE_BAUD * 16;
+ if (port->mapbase)
+ port->membase = earlycon_map(port->mapbase, 64);
+
+ earlycon_init(&early_console_dev, match->name);
+ err = match->setup(&early_console_dev, buf);
+ earlycon_print_info(&early_console_dev);
+ if (err < 0)
+ return err;
+ if (!early_console_dev.con->write)
+ return -ENODEV;
+
+ register_console(early_console_dev.con);
+ return 0;
+}
+
+/**
+ * setup_earlycon - match and register earlycon console
+ * @buf: earlycon param string
+ *
+ * Registers the earlycon console matching the earlycon specified
+ * in the param string @buf. Acceptable param strings are of the form
+ * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
+ * <name>,0x<addr>,<options>
+ * <name>,<options>
+ * <name>
+ *
+ * Only for the third form does the earlycon setup() method receive the
+ * <options> string in the 'options' parameter; all other forms set
+ * the parameter to NULL.
+ *
+ * Returns 0 if an attempt to register the earlycon was made,
+ * otherwise negative error code
+ */
+int __init setup_earlycon(char *buf)
+{
+ const struct earlycon_id *match;
+ bool empty_compatible = true;
+
+ if (!buf || !buf[0])
+ return -EINVAL;
+
+ if (console_is_registered(&early_con))
+ return -EALREADY;
+
+again:
+ for (match = __earlycon_table; match < __earlycon_table_end; match++) {
+ size_t len = strlen(match->name);
+
+ if (strncmp(buf, match->name, len))
+ continue;
+
+ /* prefer entries with empty compatible */
+ if (empty_compatible && *match->compatible)
+ continue;
+
+ if (buf[len]) {
+ if (buf[len] != ',')
+ continue;
+ buf += len + 1;
+ } else
+ buf = NULL;
+
+ return register_earlycon(buf, match);
+ }
+
+ if (empty_compatible) {
+ empty_compatible = false;
+ goto again;
+ }
+
+ return -ENOENT;
+}
+
+/*
+ * This defers the initialization of the early console until after ACPI has
+ * been initialized.
+ */
+bool earlycon_acpi_spcr_enable __initdata;
+
+/* early_param wrapper for setup_earlycon() */
+static int __init param_setup_earlycon(char *buf)
+{
+ int err;
+
+ /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
+ if (!buf || !buf[0]) {
+ if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
+ earlycon_acpi_spcr_enable = true;
+ return 0;
+ } else if (!buf) {
+ return early_init_dt_scan_chosen_stdout();
+ }
+ }
+
+ err = setup_earlycon(buf);
+ if (err == -ENOENT || err == -EALREADY)
+ return 0;
+ return err;
+}
+early_param("earlycon", param_setup_earlycon);
+
+#ifdef CONFIG_OF_EARLY_FLATTREE
+
+int __init of_setup_earlycon(const struct earlycon_id *match,
+ unsigned long node,
+ const char *options)
+{
+ int err;
+ struct uart_port *port = &early_console_dev.port;
+ const __be32 *val;
+ bool big_endian;
+ u64 addr;
+
+ if (console_is_registered(&early_con))
+ return -EALREADY;
+
+ spin_lock_init(&port->lock);
+ port->iotype = UPIO_MEM;
+ addr = of_flat_dt_translate_address(node);
+ if (addr == OF_BAD_ADDR) {
+ pr_warn("[%s] bad address\n", match->name);
+ return -ENXIO;
+ }
+ port->mapbase = addr;
+
+ val = of_get_flat_dt_prop(node, "reg-offset", NULL);
+ if (val)
+ port->mapbase += be32_to_cpu(*val);
+ port->membase = earlycon_map(port->mapbase, SZ_4K);
+
+ val = of_get_flat_dt_prop(node, "reg-shift", NULL);
+ if (val)
+ port->regshift = be32_to_cpu(*val);
+ big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
+ (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
+ of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
+ val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
+ if (val) {
+ switch (be32_to_cpu(*val)) {
+ case 1:
+ port->iotype = UPIO_MEM;
+ break;
+ case 2:
+ port->iotype = UPIO_MEM16;
+ break;
+ case 4:
+ port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
+ break;
+ default:
+ pr_warn("[%s] unsupported reg-io-width\n", match->name);
+ return -EINVAL;
+ }
+ }
+
+ val = of_get_flat_dt_prop(node, "current-speed", NULL);
+ if (val)
+ early_console_dev.baud = be32_to_cpu(*val);
+
+ val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
+ if (val)
+ port->uartclk = be32_to_cpu(*val);
+
+ if (options) {
+ early_console_dev.baud = simple_strtoul(options, NULL, 0);
+ strscpy(early_console_dev.options, options,
+ sizeof(early_console_dev.options));
+ }
+ earlycon_init(&early_console_dev, match->name);
+ err = match->setup(&early_console_dev, options);
+ earlycon_print_info(&early_console_dev);
+ if (err < 0)
+ return err;
+ if (!early_console_dev.con->write)
+ return -ENODEV;
+
+
+ register_console(early_console_dev.con);
+ return 0;
+}
+
+#endif /* CONFIG_OF_EARLY_FLATTREE */