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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2015-10-28 12:46:05 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-13 19:59:48 -0800 |
| commit | bd94c4077a0b2ecc35562c294f80f3659ecd8499 (patch) | |
| tree | 939d81f6945ce1b0925ab4bf6f7e40c399057e17 /Documentation/kernel-parameters.txt | |
| parent | 004e2ed5cc6d89201140ca96693bf9c0b2945f43 (diff) | |
| download | lwn-bd94c4077a0b2ecc35562c294f80f3659ecd8499.tar.gz lwn-bd94c4077a0b2ecc35562c294f80f3659ecd8499.zip | |
serial: support 16-bit register interface for console
Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are
supported for the 8250 console, but the 16-bit (MMIO16) is not.
The 8250 UART device on my board is connected to a 16-bit bus and
my main motivation is to use earlycon with it.
(Refer to arch/arm/boot/dts/uniphier-support-card.dtsi)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 742f69d18fc8..054e11d33b6b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -721,16 +721,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] + uart[8250],mmio16,<addr>[,options] uart[8250],mmio32,<addr>[,options] uart[8250],0x<addr>[,options] Start an early, polled-mode console on the 8250/16550 UART at the specified I/O port or MMIO address, switching to the matching ttyS device later. MMIO inter-register address stride is either 8-bit - (mmio) or 32-bit (mmio32). - If none of [io|mmio|mmio32], <addr> is assumed to be - equivalent to 'mmio'. 'options' are specified in the - same format described for ttyS above; if unspecified, + (mmio), 16-bit (mmio16), or 32-bit (mmio32). + If none of [io|mmio|mmio16|mmio32], <addr> is assumed + to be equivalent to 'mmio'. 'options' are specified in + the same format described for ttyS above; if unspecified, the h/w is not re-initialized. hvc<n> Use the hypervisor console device <n>. This is for |