From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH v1 1/1] x86/early_printk: Use 'mmio32' for consistency
Date: Mon, 7 Apr 2025 20:22:14 +0300 [thread overview]
Message-ID: <20250407172214.792745-1-andriy.shevchenko@linux.intel.com> (raw)
First of all, using 'mmio' prevents proper implementation of 8-bit accessors.
Second, it's simply inconsistent with uart8250 set of options. Rename it to
'mmio32'. While at it, remove rather misleading comment in the documentation.
From now on mmio32 is self-explanatory and pciserial supports not only 32-bit
MMIO accessors.
Fixes: 3181424aeac2 ("x86/early_printk: Add support for MMIO-based UARTs")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Documentation/admin-guide/kernel-parameters.txt | 5 +----
arch/x86/kernel/early_printk.c | 6 +++---
2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 76e538c77e31..d9fd26b95b34 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1407,18 +1407,15 @@
earlyprintk=serial[,0x...[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
+ earlyprintk=mmio32,membase[,{nocfg|baudrate}]
earlyprintk=pciserial[,force],bus:device.function[,{nocfg|baudrate}]
earlyprintk=xdbc[xhciController#]
earlyprintk=bios
- earlyprintk=mmio,membase[,{nocfg|baudrate}]
earlyprintk is useful when the kernel crashes before
the normal console is initialized. It is not enabled by
default because it has some cosmetic problems.
- Only 32-bit memory addresses are supported for "mmio"
- and "pciserial" devices.
-
Use "nocfg" to skip UART configuration, assume
BIOS/firmware has configured UART correctly.
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index b70e6e99fb17..dc053641698c 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -424,10 +424,10 @@ static int __init setup_early_printk(char *buf)
keep = (strstr(buf, "keep") != NULL);
while (*buf != '\0') {
- if (!strncmp(buf, "mmio", 4)) {
- early_mmio_serial_init(buf + 4);
+ if (!strncmp(buf, "mmio32", 6)) {
+ buf += 6;
+ early_mmio_serial_init(buf);
early_console_register(&early_serial_console, keep);
- buf += 4;
}
if (!strncmp(buf, "serial", 6)) {
buf += 6;
--
2.47.2
next reply other threads:[~2025-04-07 17:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-07 17:22 Andy Shevchenko [this message]
2025-04-09 10:23 ` Ingo Molnar
2025-04-09 11:44 ` [tip: x86/urgent] x86/early_printk: Use 'mmio32' for consistency, fix comments tip-bot2 for Andy Shevchenko
2025-04-08 20:46 [PATCH v1 1/1] x86/early_printk: Use 'mmio32' for consistency dmkhn
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