From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 191E44AEE2 for ; Wed, 9 Apr 2025 02:23:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=140.211.166.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744165390; cv=none; b=UN/2VRL3YRcNVHGFCpY+4yLtrjOhhA6s7SBvfvp/2gBl59z58GrCEPFzUvoGdVNMyyFjjKBaA6HNmRRLtG26Q/5W2OZDuG1IV5Cl+Pb3AE/54FGlX1IdnBzbl3ce/YwwIc53qDQrivczNUgip/TMq4V+Z8hufBmE7AIqOr/g2gs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744165390; c=relaxed/simple; bh=YpYVYQafOn9FkO4JJLzXWIVv3sLZg48zJmwC5hQslag=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JGya841hIEzLtl3/R6f/ovUrCKkFi56k78Niqxu+ido9VEMFyJL2aMSBqMT04vNv9TK419tOaQ10gEqGbeAtKC/YJ+nkSabU/MVNOHTHf13XHbwWUAUvPlf+Z8tond9xIgwxQ2xboUwZesTppAzaS+5L2AO8LHyRZp6YJ9qAJu4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org; spf=pass smtp.mailfrom=gentoo.org; arc=none smtp.client-ip=140.211.166.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gentoo.org Received: from localhost (unknown [116.232.27.72]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dlan) by smtp.gentoo.org (Postfix) with ESMTPSA id C2748343221; Wed, 09 Apr 2025 02:23:07 +0000 (UTC) Date: Wed, 9 Apr 2025 02:23:03 +0000 From: Yixun Lan To: Andre Przywara Cc: Jagan Teki , u-boot@lists.denx.de, Tom Rini , Jernej Skrabec , Samuel Holland , linux-sunxi@lists.linux.dev Subject: Re: [PATCH] sunxi: add "fake" FEL pin support Message-ID: <20250409022303-GYA17019@gentoo> References: <20250408235959.10720-1-andre.przywara@arm.com> Precedence: bulk X-Mailing-List: linux-sunxi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250408235959.10720-1-andre.przywara@arm.com> Hi Andre Przywara: I can understand the motivation behind this patch, which I think it's a good addition to BROM FEL mode.. On 00:59 Wed 09 Apr , Andre Przywara wrote: > Some boards with Allwinner SoCs feature a "FEL" key, sometimes also > labelled "uboot", which triggers the BootROM FEL mode, when pressed upon > power-on or reset. This allows to access the SoC's memory via USB OTG, > and to upload and execute code. There is a tool to upload our U-Boot image > and immediately boot it, when the SoC is in FEL mode. > > To mimic this convenient behaviour on boards without such a dedicated key, > we can query a GPIO pin very early in the SPL boot, then trigger the > BootROM FEL routine. There has not been much of a SoC or board setup at > this point, so we enter the BROM in a rather pristine state still. On > 64-bit SoCs the required AArch32 reset guarantees a clean CPU state anyway. > > Any GPIO can be used for that, and a board (or a user) is expected to > specify the GPIO name using the CONFIG_SUNXI_FAKE_FEL_PIN Kconfig variable. > When this variable is not set, the compiler will optimise away the call. > is it possible to provide a dts interface to specify the gpio pin? it would be more convenient, but a CONFIG option would be fine.. > Call the code first thing in board_init_f(), which is the first sunxi > specific C routine. > > Signed-off-by: Andre Przywara > --- > arch/arm/mach-sunxi/Kconfig | 9 +++++++++ > arch/arm/mach-sunxi/board.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig > index 25b47ada7ad..912d3a3a650 100644 > --- a/arch/arm/mach-sunxi/Kconfig > +++ b/arch/arm/mach-sunxi/Kconfig > @@ -789,6 +789,15 @@ config MMC_SUNXI_SLOT_EXTRA > slot or emmc on mmc1 - mmc3. Setting this to 1, 2 or 3 will enable > support for this. > > +config SUNXI_FAKE_FEL_PIN > + string "fake FEL GPIO pin" > + default "" > + ---help--- > + Define a GPIO that shall force entering FEL mode when a button > + connected to this pin is pressed at boot time. > + This takes a string in the format understood by sunxi_name_to_gpio, > + e.g. PH1 for pin 1 of port H. > + > config I2C0_ENABLE > bool "Enable I2C/TWI controller 0" > default y if MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || MACH_SUN8I_R40 > diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c > index 701899ee4b2..ea0e7bb381d 100644 > --- a/arch/arm/mach-sunxi/board.c > +++ b/arch/arm/mach-sunxi/board.c > @@ -457,8 +457,38 @@ u32 spl_mmc_boot_mode(struct mmc *mmc, const u32 boot_device) > return result; > } > > +static void check_fake_fel_button(void) > +{ > + u32 brom_entry = 0x20; > + int pin, value, mux; > + > + /* check for empty string at compile time */ > + if (sizeof(CONFIG_SUNXI_FAKE_FEL_PIN) == sizeof("")) > + return; > + > + pin = sunxi_name_to_gpio(CONFIG_SUNXI_FAKE_FEL_PIN); > + if (pin < 0) > + return; > + > + mux = sunxi_gpio_get_cfgpin(pin); > + sunxi_gpio_set_cfgpin(pin, SUNXI_GPIO_INPUT); > + value = gpio_get_value(pin); > + sunxi_gpio_set_cfgpin(pin, mux); > + > + if (value) > + return; so will skip EFL mode when "GPIO == 1" (which means gpio high level)? maybe we should document in the Kconfig help section: setting GPIO low to enter FEL mode or even great if the gpio can be configurable for FEL mode > + > + /* Older SoCs maps the BootROM high in the address space. */ > + if (fel_stash.sctlr & BIT(13)) > + brom_entry |= 0xffff0000; > + > + return_to_fel(0, brom_entry); > +} > + > void board_init_f(ulong dummy) > { > + check_fake_fel_button(); > + > sunxi_sram_init(); > > /* Enable non-secure access to some peripherals */ > -- > 2.46.3 > -- Yixun Lan (dlan) Gentoo Linux Developer GPG Key ID AABEFD55