Add support the "mmio32" earlycon option for the pl011 device. If
specified in the earlycon parameter, all reads/writes to pl011 registers
during early console will use 32-bit accessors. Normally the function
uses 8-bit writes.
Normal console uses the "access_32b" field of the vendor data structure
to determine whether the registers needs 32-bit accessors. Early console
is used before the vendor data is available, so we need a different
mechanism to choose the accessor.
Example:
earlycon=pl011,mmio32,0x3ced1000
Signed-off-by: Timur Tabi <timur@xxxxxxxxxxxxxx>
---
This patch applies on top of Russell's 12-part amba-pl011.c patchset.
Documentation/kernel-parameters.txt | 5 ++++-
drivers/tty/serial/amba-pl011.c | 9 ++++++---
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 22a4b68..2436f62 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -992,10 +992,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
unspecified, the h/w is not initialized.
pl011,<addr>
+ pl011,mmio32,<addr>
Start an early, polled-mode console on a pl011 serial
port at the specified address. The pl011 serial port
must already be setup and configured. Options are not
- yet supported.
+ yet supported. If 'mmio32' is specified, then only
+ the driver will use only 32-bit accessors to read/write
+ the device registers.
msm_serial,<addr>
Start an early, polled-mode console on an msm serial
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 373b152..6643ed9 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2301,10 +2301,13 @@ static struct console amba_console = {
static void pl011_putc(struct uart_port *port, int c)
{
- while (readl(port->membase + REG_FR) & UART01x_FR_TXFF)
+ while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
;
- writeb(c, port->membase + REG_DR);
- while (readl(port->membase + REG_FR) & UART01x_FR_BUSY)
+ if (port->iotype == UPIO_MEM32)
+ writel(c, port->membase + UART01x_DR);
+ else
+ writeb(c, port->membase + UART01x_DR);
+ while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY)
;
}
--
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
