From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-yk0-x22d.google.com ([2607:f8b0:4002:c07::22d]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zh0Eq-0005bn-D8 for barebox@lists.infradead.org; Tue, 29 Sep 2015 19:06:57 +0000 Received: by ykdg206 with SMTP id g206so16882762ykd.1 for ; Tue, 29 Sep 2015 12:06:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20150929070523.GP7858@pengutronix.de> References: <1443362931-1881-1-git-send-email-vicencb@gmail.com> <20150929070523.GP7858@pengutronix.de> Date: Tue, 29 Sep 2015 20:06:35 +0100 Message-ID: From: vj List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] xload: be more flexible when searching for second stage bootloader. To: Sascha Hauer Cc: barebox@lists.infradead.org On Tue, Sep 29, 2015 at 8:05 AM, Sascha Hauer wrote: > On Sun, Sep 27, 2015 at 03:08:51PM +0100, Vicente Bergas wrote: >> A first stage bootloader can read fat and ext4 filesystems, and >> even both can be compiled-in at the same time. >> But then xload has a hardcoded fat filesystem mount option which >> renders ext4 unusable. >> This patch tries to mount it as ext4 if the fat attempt fails. >> >> Then, a typical use case of an ext4 formatted filesystem >> is it to be a standard linux filesystem, which contains >> boot-related files in /boot. So, when searching for the second stage >> bootloader, try /boot/barebox.bin after not finding it in /barebox.bin >> >> Signed-off-by: Vicente Bergas >> --- >> arch/arm/mach-omap/xload.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/arm/mach-omap/xload.c b/arch/arm/mach-omap/xload.c >> index ebcbcbc..c5e29f8 100644 >> --- a/arch/arm/mach-omap/xload.c >> +++ b/arch/arm/mach-omap/xload.c >> @@ -118,6 +118,8 @@ static void *omap_xload_boot_mmc(void) >> partname = asprintf("%s.0", diskdev); >> >> ret = mount(partname, "fat", "/", NULL); >> + if (ret) >> + ret = mount(partname, "ext4", "/", NULL); > > It should also be possible to pass NULL as fs type in which case we > automatically detect the fs type. Could you check that? I didn't know that. This way it would be nicer and cleaner! So it has been tested but it didn't work :( mount calls detect_fs, detect_fs calls file_name_detect_type and file_name_detect_type calls open. open fails to open the "mmc0.0" file name Then I changed the name to "/dev/mmc0.0" but it failed the same way. The open return code is -2. (It's been tested on a BeagleBoneBlack) > > Where does the MLO come from when you don't have a FAT on your MMC/SD > device? Don't we need FAT on the first partition to let the boot ROM > load the MLO? There are small differences in OMAP variants, so here there is only one example that refers to the AM3359 on board of a BeagleBoneBlack: As stated in the AM335x Sitara Processors Technical Reference Manual Rev L.pdf (http://www.ti.com/lit/pdf/spruh73) Section 26.1.7.5.5 page 4940 In raw mode the booting image can be located at one of the four consecutive locations in the main area: offset 0x0 / 0x20000 (128KB) / 0x40000 (256KB) / 0x60000 (384KB). The raw mode is detected by reading sectors #0, #256, #512, #768. So, the first 128KB block can hold an MBR plus partition table, then a raw image of the MLO file can be present at offset 128KB followed by the disk partitions. In section 26.1.7.5.3 page 4939 figure 26-17 MMC/SD Booting states that raw mode detection is performed before searching for the MLO file in a filesystem. All in all, it is possible to have a "fat-free" SD-card. Regards, Vicente. > > Sascha > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox