From: Tomasz Figa <t.figa@xxxxxxxxxxx>
This patch adds support for early console initialized from device tree
and kernel command line to all variants of Samsung serial driver.
Signed-off-by: Tomasz Figa <t.figa@xxxxxxxxxxx>
[mszyprow: added support for command line based initialization,
fixed comments, added documentation]
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Reviewed-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
Tested-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 12 +++++
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/samsung.c | 103 ++++++++++++++++++++++++++++++++++++
3 files changed, 116 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7dbe5ec9d9cd..24f363108ab3 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -961,6 +961,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
smh Use ARM semihosting calls for early console.
+ s3c2410,<addr>
+ s3c2412,<addr>
+ s3c2440,<addr>
+ s3c6400,<addr>
+ s5pv210,<addr>
+ exynos4210,<addr>
+ Use early console provided by serial driver available
+ on Samsung SoCs, requires selecting proper type and
+ a correct base address of the selected UART port. The
+ serial port must already be setup and configured.
+ Options are not yet supported.
+
earlyprintk= [X86,SH,BLACKFIN,ARM,M68k]
earlyprintk=vga
earlyprintk=efi
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 649b784081c7..50997be6cf6d 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -241,6 +241,7 @@ config SERIAL_SAMSUNG
tristate "Samsung SoC serial support"
depends on PLAT_SAMSUNG || ARCH_EXYNOS
select SERIAL_CORE
+ select SERIAL_EARLYCON
help
Support for the on-chip UARTs on the Samsung S3C24XX series CPUs,
providing /dev/ttySAC0, 1 and 2 (note, some machines may not
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index c78f43a481ce..8ad453a5d845 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1856,6 +1856,109 @@ static struct platform_driver samsung_serial_driver = {
module_platform_driver(samsung_serial_driver);
+/*
+ * Early console.
+ */
+
+struct samsung_early_console_data {
+ u32 txfull_mask;
+};
+
+static void samsung_early_busyuart(struct uart_port *port)
+{
+ while (!(readl(port->membase + S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXFE))
+ ;
+}
+
+static void samsung_early_busyuart_fifo(struct uart_port *port)
+{
+ struct samsung_early_console_data *data = port->private_data;
+
+ while (readl(port->membase + S3C2410_UFSTAT) & data->txfull_mask)
+ ;
+}
+
+static void samsung_early_putc(struct uart_port *port, int c)
+{
+ if (readl(port->membase + S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE)
+ samsung_early_busyuart_fifo(port);
+ else
+ samsung_early_busyuart(port);
+
+ writeb(c, port->membase + S3C2410_UTXH);
+}
+
+static void samsung_early_write(struct console *con, const char *s, unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, samsung_early_putc);
+}
+
+static int __init samsung_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = samsung_early_write;
+ return 0;
+}
+
+/* S3C2410 */
+static struct samsung_early_console_data s3c2410_early_console_data = {
+ .txfull_mask = S3C2410_UFSTAT_TXFULL,
+};
+
+static int __init s3c2410_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->port.private_data = &s3c2410_early_console_data;
+ return samsung_early_console_setup(device, opt);
+}
+OF_EARLYCON_DECLARE(s3c2410, "samsung,s3c2410-uart",
+ s3c2410_early_console_setup);
+EARLYCON_DECLARE(s3c2410, s3c2410_early_console_setup);
+
+/* S3C2412, S3C2440, S3C64xx */
+static struct samsung_early_console_data s3c2440_early_console_data = {
+ .txfull_mask = S3C2440_UFSTAT_TXFULL,
+};
+
+static int __init s3c2440_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->port.private_data = &s3c2440_early_console_data;
+ return samsung_early_console_setup(device, opt);
+}
+OF_EARLYCON_DECLARE(s3c2412, "samsung,s3c2412-uart",
+ s3c2440_early_console_setup);
+OF_EARLYCON_DECLARE(s3c2440, "samsung,s3c2440-uart",
+ s3c2440_early_console_setup);
+OF_EARLYCON_DECLARE(s3c6400, "samsung,s3c6400-uart",
+ s3c2440_early_console_setup);
+EARLYCON_DECLARE(s3c2412, s3c2440_early_console_setup);
+EARLYCON_DECLARE(s3c2440, s3c2440_early_console_setup);
+EARLYCON_DECLARE(s3c6400, s3c2440_early_console_setup);
+
+/* S5PV210, EXYNOS */
+static struct samsung_early_console_data s5pv210_early_console_data = {
+ .txfull_mask = S5PV210_UFSTAT_TXFULL,
+};
+
+static int __init s5pv210_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->port.private_data = &s5pv210_early_console_data;
+ return samsung_early_console_setup(device, opt);
+}
+OF_EARLYCON_DECLARE(s5pv210, "samsung,s5pv210-uart",
+ s5pv210_early_console_setup);
+OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",
+ s5pv210_early_console_setup);
+EARLYCON_DECLARE(s5pv210, s5pv210_early_console_setup);
+EARLYCON_DECLARE(exynos4210, s5pv210_early_console_setup);
+
MODULE_ALIAS("platform:samsung-uart");
MODULE_DESCRIPTION("Samsung SoC Serial port driver");
MODULE_AUTHOR("Ben Dooks <ben@xxxxxxxxxxxx>");
--
1.9.2
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