Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754640AbaKYLRc (ORCPT ); Tue, 25 Nov 2014 06:17:32 -0500 Received: from mail-wi0-f177.google.com ([209.85.212.177]:62182 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754143AbaKYLR3 (ORCPT ); Tue, 25 Nov 2014 06:17:29 -0500 Date: Tue, 25 Nov 2014 11:17:24 +0000 From: Leif Lindholm To: Mark Rutland Cc: "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "grant.likely@linaro.org" , "robh+dt@kernel.org" , "plagnioj@jcrosoft.com" , "ijc@debian.org" Subject: Re: [PATCH] of: support passing console options with stdout-path Message-ID: <20141125111724.GC2361@bivouac.eciton.net> References: <1416867838-18652-1-git-send-email-leif.lindholm@linaro.org> <20141125103504.GA21525@leverpostej> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141125103504.GA21525@leverpostej> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 25, 2014 at 10:35:04AM +0000, Mark Rutland wrote: > On Mon, Nov 24, 2014 at 10:23:58PM +0000, Leif Lindholm wrote: > > Support specifying console options (like with console=ttyXN,) > > by appending them to the stdout-path property after a separating ':'. > > > > Example: > > stdout-path = "uart0:115200"; > > I would very much like to be able to use this -- it will allow > distributions to boot on a board without having to know _anything_ about > the console UART until userspace is up, which would make it possible to > have a completely generic installer image, without requiring the > platform to provide bootargs. > > My only concern is that this conflates the set of kernel command line > options for the UART wit the DT binding for it. I don't know how good > people are at keeping those options stable, and I know they are > currently not documented -- we would need to add a stdout-path options > section to relevant UART bindings. I don't disagree. Current options are fairly well defined and stable, at least for any driver that uses uart_parse_options() (documented in Documentation/serial/driver). >From drivers/tty/serial/serial_core.c: * uart_parse_options decodes a string containing the serial console * options. The format of the string is , * eg: 115200n8r / Leif > > > > > This patch also modifies of_find_node_by_path() to match only the > > portion of the path before a ':'. > > > > Signed-off-by: Leif Lindholm > > --- > > drivers/of/base.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/of/base.c b/drivers/of/base.c > > index 3823edf..89c6b33 100644 > > --- a/drivers/of/base.c > > +++ b/drivers/of/base.c > > @@ -37,6 +37,7 @@ EXPORT_SYMBOL(of_allnodes); > > struct device_node *of_chosen; > > struct device_node *of_aliases; > > struct device_node *of_stdout; > > +static char *of_stdout_options; > > > > struct kset *of_kset; > > > > @@ -703,6 +704,8 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent, > > if (!len) > > return NULL; > > > > + len = strchrnul(path, ':') - path; > > + > > __for_each_child_of_node(parent, child) { > > const char *name = strrchr(child->full_name, '/'); > > if (WARN(!name, "malformed device_node %s\n", child->full_name)) > > @@ -747,6 +750,8 @@ struct device_node *of_find_node_by_path(const char *path) > > if (!of_aliases) > > return NULL; > > > > + len = strchrnul(path, ':') - path; > > + > > for_each_property_of_node(of_aliases, pp) { > > if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) { > > np = of_find_node_by_path(pp->value); > > @@ -1830,8 +1835,12 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) > > name = of_get_property(of_chosen, "linux,stdout-path", NULL); > > if (IS_ENABLED(CONFIG_PPC) && !name) > > name = of_get_property(of_aliases, "stdout", NULL); > > - if (name) > > + if (name) { > > of_stdout = of_find_node_by_path(name); > > + of_stdout_options = strchr(name, ':'); > > + if (of_stdout_options != NULL) > > + of_stdout_options++; > > + } > > } > > > > if (!of_aliases) > > @@ -1957,7 +1966,7 @@ bool of_console_check(struct device_node *dn, char *name, int index) > > { > > if (!dn || dn != of_stdout || console_set_on_cmdline) > > return false; > > - return !add_preferred_console(name, index, NULL); > > + return !add_preferred_console(name, index, of_stdout_options); > > } > > EXPORT_SYMBOL_GPL(of_console_check); > > > > -- > > 1.9.1 > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/