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| author |   Timur Tabi <timur@codeaurora.org> | 2017-03-31 17:05:02 -0500 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-01 11:07:29 +0200 |
| commit | e53e597fd4c4a0b6ae58e57d76a240927fd17eaa (patch) | |
| tree | 6fcc6f9220d0ec88b84a1c10803690303f34245f /drivers/tty | |
| parent | serial: 8250_EXAR: fix duplicate Kconfig text and add missing help text (diff) | |
| download | linux-dev-e53e597fd4c4a0b6ae58e57d76a240927fd17eaa.tar.xz linux-dev-e53e597fd4c4a0b6ae58e57d76a240927fd17eaa.zip | |
tty: pl011: fix earlycon work-around for QDF2400 erratum 44
The work-around for the Qualcomm Datacenter Technologies QDF2400
erratum 44 sets the "qdf2400_e44_present" global variable if the
work-around is needed. However, this check does not happen until after
earlycon is initialized, which means the work-around is not
used, and the console hangs as soon as it displays one character.
Fixes: d8a4995bcea1 ("tty: pl011: Work around QDF2400 E44 stuck BUSY bit")
Signed-off-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 56f92d7348bf..b0a377725d63 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2452,18 +2452,37 @@ static void pl011_early_write(struct console *con, const char *s, unsigned n) uart_console_write(&dev->port, s, n, pl011_putc); } +/* + * On non-ACPI systems, earlycon is enabled by specifying + * "earlycon=pl011,<address>" on the kernel command line. + * + * On ACPI ARM64 systems, an "early" console is enabled via the SPCR table, + * by specifying only "earlycon" on the command line. Because it requires + * SPCR, the console starts after ACPI is parsed, which is later than a + * traditional early console. + * + * To get the traditional early console that starts before ACPI is parsed, + * specify the full "earlycon=pl011,<address>" option. + */ static int __init pl011_early_console_setup(struct earlycon_device *device, const char *opt) { if (!device->port.membase) return -ENODEV; - device->con->write = qdf2400_e44_present ? - qdf2400_e44_early_write : pl011_early_write; + /* On QDF2400 SOCs affected by Erratum 44, the "qdf2400_e44" must + * also be specified, e.g. "earlycon=pl011,<address>,qdf2400_e44". + */ + if (!strcmp(device->options, "qdf2400_e44")) + device->con->write = qdf2400_e44_early_write; + else + device->con->write = pl011_early_write; + return 0; } OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup); OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup); +EARLYCON_DECLARE(qdf2400_e44, pl011_early_console_setup); #else #define AMBA_CONSOLE NULL |