From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161353AbcFHHR2 (ORCPT ); Wed, 8 Jun 2016 03:17:28 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:3100 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321AbcFHHRX (ORCPT ); Wed, 8 Jun 2016 03:17:23 -0400 Subject: Re: [PATCH] ARM: at91: debug: use DEBUG_UART_VIRT To: Alexandre Belloni References: <1465313079-6307-1-git-send-email-alexandre.belloni@free-electrons.com> <5756ECC5.6020908@atmel.com> <20160607162301.GL3363@piout.net> CC: Russell King , Arnd Bergmann , "Boris Brezillon" , , From: Nicolas Ferre Organization: atmel Message-ID: <5757C67E.3000301@atmel.com> Date: Wed, 8 Jun 2016 09:17:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160607162301.GL3363@piout.net> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.161.30.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 07/06/2016 18:23, Alexandre Belloni a écrit : > On 07/06/2016 at 17:48:21 +0200, Nicolas Ferre wrote : >> Le 07/06/2016 17:24, Alexandre Belloni a écrit : >>> AT91 still uses an offset (0x0100 0000) from the physical address to map >>> the debug UART. This is unfortunate as for some platforms (sama5d3 and >>> earlier), it ends up in the PCI zone and PCI is enabled in multi_v7. >>> Switch to DEBUG_UART_VIRT to solve that. >>> >>> Tested on sama5d3 and 9g20. >>> >>> Signed-off-by: Alexandre Belloni >> >> People using their old defconfigs must pay attention to this change... >> but it's true that it's a debug configuration anyway... >> > > I really doubt people are letting DEBUG_LL enabled in a production > kernel... > >>> diff --git a/arch/arm/include/debug/at91.S b/arch/arm/include/debug/at91.S >>> index d4ae3b8e2426..0098401e5aeb 100644 >>> --- a/arch/arm/include/debug/at91.S >>> +++ b/arch/arm/include/debug/at91.S >>> @@ -9,14 +9,6 @@ >>> * >>> */ >>> >>> -#ifdef CONFIG_MMU >>> -#define AT91_IO_P2V(x) ((x) - 0x01000000) >>> -#else >>> -#define AT91_IO_P2V(x) (x) >>> -#endif >>> - >>> -#define AT91_DEBUG_UART_VIRT AT91_IO_P2V(CONFIG_DEBUG_UART_PHYS) >>> - >>> #define AT91_DBGU_SR (0x14) /* Status Register */ >>> #define AT91_DBGU_THR (0x1c) /* Transmitter Holding Register */ >>> #define AT91_DBGU_TXRDY (1 << 1) /* Transmitter Ready */ >>> @@ -24,7 +16,7 @@ >>> >>> .macro addruart, rp, rv, tmp >>> ldr \rp, =CONFIG_DEBUG_UART_PHYS @ System peripherals (phys address) >>> - ldr \rv, =AT91_DEBUG_UART_VIRT @ System peripherals (virt address) >>> + ldr \rv, =CONFIG_DEBUG_UART_VIRT @ System peripherals (virt address) >> >> Shouldn't we protect the use of this defined value with some >> #warning "Beware the value CONFIG_DEBUG_UART_VIRT haven't been defined: >> is it intentional" >> or even #error? >> >> or something like that? >> > > Well, those that are using this feature are supposed to know what they > are doing. There is now protection for CONFIG_DEBUG_UART_PHYS anyway. So, I know that developers are sensible people and know what they're doing but still... what about having a protection for both anyway... instead of silently crashing at runtime? Bye, -- Nicolas Ferre