From 3631e48df0dbfcce3b08f0ccafcaa587657379cd Mon Sep 17 00:00:00 2001 From: Woody Lin Date: Wed, 2 Mar 2022 19:49:23 +0800 Subject: serial: samsung: Add samsung_early_read to support early kgdboc The 'kgdboc_earlycon_init' looks for boot console that has both .read and .write callbacks. Adds 'samsung_early_read' to samsung_tty.c's early console to support kgdboc. Reviewed-by: Krzysztof Kozlowski Signed-off-by: Woody Lin Link: https://lore.kernel.org/r/20220302114923.144523-1-woodylin@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/samsung_tty.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index 2bde7bde7116..95018a847023 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -2949,6 +2949,7 @@ static void wr_reg_barrier(struct uart_port *port, u32 reg, u32 val) struct samsung_early_console_data { u32 txfull_mask; + u32 rxfifo_mask; }; static void samsung_early_busyuart(struct uart_port *port) @@ -2983,6 +2984,26 @@ static void samsung_early_write(struct console *con, const char *s, uart_console_write(&dev->port, s, n, samsung_early_putc); } +static int samsung_early_read(struct console *con, char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + const struct samsung_early_console_data *data = dev->port.private_data; + int ch, ufstat, num_read = 0; + + while (num_read < n) { + ufstat = rd_regl(&dev->port, S3C2410_UFSTAT); + if (!(ufstat & data->rxfifo_mask)) + break; + ch = rd_reg(&dev->port, S3C2410_URXH); + if (ch == NO_POLL_CHAR) + break; + + s[num_read++] = ch; + } + + return num_read; +} + static int __init samsung_early_console_setup(struct earlycon_device *device, const char *opt) { @@ -2990,12 +3011,14 @@ static int __init samsung_early_console_setup(struct earlycon_device *device, return -ENODEV; device->con->write = samsung_early_write; + device->con->read = samsung_early_read; return 0; } /* S3C2410 */ static struct samsung_early_console_data s3c2410_early_console_data = { .txfull_mask = S3C2410_UFSTAT_TXFULL, + .rxfifo_mask = S3C2410_UFSTAT_RXFULL | S3C2410_UFSTAT_RXMASK, }; static int __init s3c2410_early_console_setup(struct earlycon_device *device, @@ -3011,6 +3034,7 @@ OF_EARLYCON_DECLARE(s3c2410, "samsung,s3c2410-uart", /* S3C2412, S3C2440, S3C64xx */ static struct samsung_early_console_data s3c2440_early_console_data = { .txfull_mask = S3C2440_UFSTAT_TXFULL, + .rxfifo_mask = S3C2440_UFSTAT_RXFULL | S3C2440_UFSTAT_RXMASK, }; static int __init s3c2440_early_console_setup(struct earlycon_device *device, @@ -3030,6 +3054,7 @@ OF_EARLYCON_DECLARE(s3c6400, "samsung,s3c6400-uart", /* S5PV210, Exynos */ static struct samsung_early_console_data s5pv210_early_console_data = { .txfull_mask = S5PV210_UFSTAT_TXFULL, + .rxfifo_mask = S5PV210_UFSTAT_RXFULL | S5PV210_UFSTAT_RXMASK, }; static int __init s5pv210_early_console_setup(struct earlycon_device *device, -- cgit v1.2.3