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authorTimur Tabi <timur@codeaurora.org>2017-03-31 17:05:02 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-01 11:07:29 +0200
commite53e597fd4c4a0b6ae58e57d76a240927fd17eaa (patch)
tree6fcc6f9220d0ec88b84a1c10803690303f34245f /drivers/tty/serial
parent49e1590c2ead870f4ae5568816241c4cb9bc1606 (diff)
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/serial')
-rw-r--r--drivers/tty/serial/amba-pl011.c23
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