[PATCH] serial: 8250_uniphier: add earlycon support
From: Peter Hurley <hidden>
Date: 2015-10-28 15:21:08
Also in:
linux-serial, lkml
Hi Masahiro, On 10/22/2015 04:39 AM, Masahiro Yamada wrote:
quoted hunk ↗ jump to hunk
This reuses the code of drivers/tty/serial/8250/8250_early.c except - Overwrite device->port.iotype and device->port.regshift for UPIO_MEM32 because of_setup_earlycon() has set them for UPIO_MEM. - Set device->baud to zero to prevent early8250_setup() from initializing the divisor register because port->uartclk does not match the frequency expected by this hardware. Signed-off-by: Masahiro Yamada <redacted> --- drivers/tty/serial/8250/8250_uniphier.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c index 245edbb..c1075c5 100644 --- a/drivers/tty/serial/8250/8250_uniphier.c +++ b/drivers/tty/serial/8250/8250_uniphier.c@@ -13,6 +13,7 @@ */ #include <linux/clk.h> +#include <linux/console.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h>@@ -34,6 +35,29 @@ struct uniphier8250_priv { spinlock_t atomic_write_lock; }; +#if IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE)
#ifdef CONFIG_SERIAL_8250_CONSOLE Customarily, IS_ENABLED() is only used in-function with control flow statements; eg., if (IS_ENABLED() && .... ) ....
+static int __init uniphier_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ /* This hardware always expects MMIO32 register interface. */
+ device->port.iotype = UPIO_MEM32;
+ device->port.regshift = 2;
+
+ /*
+ * Do not touch the divisor register in early_serial8250_setup();
+ * we assume it has been initialized by a boot loader.
+ */
+ device->baud = 0;
+
+ return early_serial8250_setup(device, options);
+}
+OF_EARLYCON_DECLARE(uniphier_uart, "socionext,uniphier-uart",
+ uniphier_early_console_setup);Please change the earlycon name to just "uniphier" or "uniphier8250"; eg., OF_EARLYCON_DECLARE(uniphier, "socionext,uniphier-uart", uniphier_early_console_setup); My earlycon series merges OF_EARLYCON_DECLARE() => EARLYCON_DECLARE() and "uniphier" is simpler on the command line. Regards, Peter Hurley
+#endif + /* * The register map is slightly different from that of 8250. * IO callbacks must be overridden for correct access to FCR, LCR, and MCR.