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authorMark Brown <broonie@kernel.org>2020-08-25 13:01:46 +0300
committerMark Brown <broonie@kernel.org>2020-08-25 13:01:46 +0300
commit3bec5b6aae830355e786e204b20a7cea38c3a8ed (patch)
treefd597b87faf55ceb2a207ee94f4feca6276696db /drivers/tty/serial/imx_earlycon.c
parenta577f3456c0a2fac3dee037c483753e6e68f3e49 (diff)
parentd012a7190fc1fd72ed48911e77ca97ba4521bccd (diff)
downloadlinux-3bec5b6aae830355e786e204b20a7cea38c3a8ed.tar.xz
Merge tag 'v5.9-rc2' into regulator-5.9
Linux 5.9-rc2
Diffstat (limited to 'drivers/tty/serial/imx_earlycon.c')
-rw-r--r--drivers/tty/serial/imx_earlycon.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/drivers/tty/serial/imx_earlycon.c b/drivers/tty/serial/imx_earlycon.c
new file mode 100644
index 000000000000..795606e1a22f
--- /dev/null
+++ b/drivers/tty/serial/imx_earlycon.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020 NXP
+ */
+
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/io.h>
+
+#define URTX0 0x40 /* Transmitter Register */
+#define UTS_TXFULL (1<<4) /* TxFIFO full */
+#define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
+
+static void imx_uart_console_early_putchar(struct uart_port *port, int ch)
+{
+ while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL)
+ cpu_relax();
+
+ writel_relaxed(ch, port->membase + URTX0);
+}
+
+static void imx_uart_console_early_write(struct console *con, const char *s,
+ unsigned count)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, count, imx_uart_console_early_putchar);
+}
+
+static int __init
+imx_console_early_setup(struct earlycon_device *dev, const char *opt)
+{
+ if (!dev->port.membase)
+ return -ENODEV;
+
+ dev->con->write = imx_uart_console_early_write;
+
+ return 0;
+}
+OF_EARLYCON_DECLARE(ec_imx6q, "fsl,imx6q-uart", imx_console_early_setup);
+OF_EARLYCON_DECLARE(ec_imx21, "fsl,imx21-uart", imx_console_early_setup);
+
+MODULE_AUTHOR("NXP");
+MODULE_DESCRIPTION("IMX earlycon driver");
+MODULE_LICENSE("GPL");