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| author |   Douglas Anderson <dianders@chromium.org> | 2020-05-07 13:08:48 -0700 |
|---|---|---|
| committer |   Daniel Thompson <daniel.thompson@linaro.org> | 2020-06-02 15:15:46 +0100 |
| commit | 205b5bdda2090d4730dabf9c0d9646cb32f2551d (patch) | |
| tree | f7543d43a640f7e1a97080b96e016760bd3ea88d /drivers/tty/serial/qcom_geni_serial.c | |
| parent | serial: kgdboc: Allow earlycon initialization to be deferred (diff) | |
| download | linux-dev-205b5bdda2090d4730dabf9c0d9646cb32f2551d.tar.xz linux-dev-205b5bdda2090d4730dabf9c0d9646cb32f2551d.zip | |
serial: qcom_geni_serial: Support kgdboc_earlycon
Implement the read() function in the early console driver. With
recent kgdb patches this allows you to use kgdb to debug fairly early
into the system boot.
We only bother implementing this if polling is enabled since kgdb
can't be enabled without that.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200507130644.v4.10.If2deff9679a62c1ce1b8f2558a8635dc837adf8c@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Diffstat (limited to 'drivers/tty/serial/qcom_geni_serial.c')
| -rw-r--r-- | drivers/tty/serial/qcom_geni_serial.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 6119090ce045..6bace1c6bb09 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1090,6 +1090,36 @@ static void qcom_geni_serial_earlycon_write(struct console *con, __qcom_geni_serial_console_write(&dev->port, s, n); } +#ifdef CONFIG_CONSOLE_POLL +static int qcom_geni_serial_earlycon_read(struct console *con, + char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + struct uart_port *uport = &dev->port; + int num_read = 0; + int ch; + + while (num_read < n) { + ch = qcom_geni_serial_get_char(uport); + if (ch == NO_POLL_CHAR) + break; + s[num_read++] = ch; + } + + return num_read; +} + +static void __init qcom_geni_serial_enable_early_read(struct geni_se *se, + struct console *con) +{ + geni_se_setup_s_cmd(se, UART_START_READ, 0); + con->read = qcom_geni_serial_earlycon_read; +} +#else +static inline void qcom_geni_serial_enable_early_read(struct geni_se *se, + struct console *con) { } +#endif + static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev, const char *opt) { @@ -1136,6 +1166,8 @@ static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev, dev->con->write = qcom_geni_serial_earlycon_write; dev->con->setup = NULL; + qcom_geni_serial_enable_early_read(&se, dev->con); + return 0; } OF_EARLYCON_DECLARE(qcom_geni, "qcom,geni-debug-uart", |