From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f195.google.com ([209.85.214.195]:37531 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726862AbfHJC0n (ORCPT ); Fri, 9 Aug 2019 22:26:43 -0400 Received: by mail-pl1-f195.google.com with SMTP id b3so45708604plr.4 for ; Fri, 09 Aug 2019 19:26:42 -0700 (PDT) Subject: Re: [PATCH v2] of/fdt: implement a "merge-cmdline" property References: <1565020400-25679-1-git-send-email-daniel@gimpelevich.san-francisco.ca.us> From: Frank Rowand Message-ID: <6772aab0-a4eb-55dc-657d-0f2b67b0d163@gmail.com> Date: Fri, 9 Aug 2019 19:26:40 -0700 MIME-Version: 1.0 In-Reply-To: <1565020400-25679-1-git-send-email-daniel@gimpelevich.san-francisco.ca.us> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org To: Daniel Gimpelevich , devicetree@vger.kernel.org Cc: Paul Burton , Frank Rowand List-ID: +Frank (me) On 8/5/19 8:53 AM, Daniel Gimpelevich wrote: > Currently, "bootargs" supplied via the "chosen" node can be used only to > supply a kernel command line as a whole. No mechanism exists in DT to add > bootargs to the existing command line instead. This is needed in order to > avoid having to update the bootloader or default bootloader config when > upgrading to a DTB and kernel pair that requires bootargs not previously > needed. > > One example use case is that OpenWrt currently supports four ARM devices by > means of locally applying the previously rejected edition of this patch. So > far, the patch has been used in production only on ARM, but architecture is > not a distinction in the design. > > On MIPS, Commit 951d223 ("MIPS: Fix CONFIG_CMDLINE handling") currently > prevents support of such a mechanism, so I am including a workaround, in > anticipation of upcoming changes. > > Signed-off-by: Daniel Gimpelevich > Fixes: 951d223 ("MIPS: Fix CONFIG_CMDLINE handling") > References: https://patchwork.linux-mips.org/patch/17659/ > --- > arch/mips/kernel/setup.c | 12 ++++++++---- > drivers/of/fdt.c | 9 +++++++-- > 2 files changed, 15 insertions(+), 6 deletions(-) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index ab349d2..9ce58f2 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -725,7 +725,10 @@ static void __init arch_mem_init(char **cmdline_p) > * CONFIG_CMDLINE ourselves below & don't want to duplicate its > * content because repeating arguments can be problematic. > */ > - strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); > + if (USE_DTB_CMDLINE) > + strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); > + else > + strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE); > > /* call board setup routine */ > plat_mem_setup(); > @@ -753,9 +756,10 @@ static void __init arch_mem_init(char **cmdline_p) > #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE) > strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > #else > - if ((USE_PROM_CMDLINE && arcs_cmdline[0]) || > - (USE_DTB_CMDLINE && !boot_command_line[0])) > + if (USE_PROM_CMDLINE) > strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE); > + else if (!strcmp(boot_command_line, " ")) > + boot_command_line[0] = '\0'; > > if (EXTEND_WITH_PROM && arcs_cmdline[0]) { > if (boot_command_line[0]) > @@ -764,7 +768,7 @@ static void __init arch_mem_init(char **cmdline_p) > } > > #if defined(CONFIG_CMDLINE_BOOL) > - if (builtin_cmdline[0]) { > + if (builtin_cmdline[0] && strcmp(boot_command_line, builtin_cmdline)) { > if (boot_command_line[0]) > strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); > strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index 9cdf14b..08c25eb 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -1055,8 +1055,13 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, > > /* Retrieve command line */ > p = of_get_flat_dt_prop(node, "bootargs", &l); > - if (p != NULL && l > 0) > - strlcpy(data, p, min(l, COMMAND_LINE_SIZE)); > + if (p != NULL && l > 0) { > + if (!of_get_flat_dt_prop(node, "merge-cmdline", NULL)) > + *(char *)data = '\0'; > + if (*(char *)data) > + strlcat(data, " ", COMMAND_LINE_SIZE); > + strlcat(data, p, min(l + strlen(data), COMMAND_LINE_SIZE)); > + } > > /* > * CONFIG_CMDLINE is meant to be a default in case nothing else >