From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0760C28D13 for ; Mon, 22 Aug 2022 15:34:17 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4MBGcS3QkWz3cdp for ; Tue, 23 Aug 2022 01:34:16 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ouIW1BYa; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:4641:c500::1; helo=dfw.source.kernel.org; envelope-from=pali@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=ouIW1BYa; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4MBGbn5jNmz3bq5 for ; Tue, 23 Aug 2022 01:33:41 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 470E96114C; Mon, 22 Aug 2022 15:33:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA02EC43470; Mon, 22 Aug 2022 15:33:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661182419; bh=L+xylg2Ga9OgepjcsWkpAAwkZaOwU0VdxyIlnOTzoP0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ouIW1BYa0TIGv3Bm6vn3QC9pMFbE1oMr/c9uk71Rv5zPHKUnr1YQfDzYxH1Ln79ez GxNdHDxBheoFb+j/l0QdnN/SjDf6p+fIiQIwTCIXF1U4Q0g6LEx2BcxFbfHmG4dWnt kw+xF9MDswN2XT1xew9ctStO5YzlCUnmzMzpYX/m5serD0eBCVHOuxb8urUr3VmZZe v0/QPB6TixrIGyeNZZdAOx4dAban0IQdEQzDpBtEm/97Wp8VKJ5o5+RqwrnKkkL8So TZ+94BoGITKV28Pq7V4IofHuV2a3un2vt3b6HiA2aV2MIKIZmFYTsn+lHBWIxJRPtf 73A2gZAQ3hx0g== Received: by pali.im (Postfix) id 1590597B; Mon, 22 Aug 2022 17:33:36 +0200 (CEST) Date: Mon, 22 Aug 2022 17:33:35 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: Christophe Leroy Subject: Re: [PATCH] powerpc: Add support for early debugging via Serial 16550 console Message-ID: <20220822153335.v5gc26jfbbqyj3et@pali> References: <20220819211254.22192-1-pali@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20180716 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nick Child , "linux-kernel@vger.kernel.org" , Paul Mackerras , "linuxppc-dev@lists.ozlabs.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Monday 22 August 2022 14:25:57 Christophe Leroy wrote: > Le 19/08/2022 à 23:12, Pali Rohár a écrit : > > Currently powerpc early debugging contains lot of platform specific > > options, but does not support standard UART / serial 16550 console. > > > > Later legacy_serial.c code supports registering UART as early debug console > > from device tree but it is not early during booting, but rather later after > > machine description code finishes. > > > > So for real early debugging via UART is current code unsuitable. > > > > Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550 > > which enable Serial 16550 console on address defined by new option > > CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option > > CONFIG_PPC_EARLY_DEBUG_16550_STRIDE. > > > > With this change it is possible to debug powerpc machine descriptor code. > > For example this early debugging code can print on serial console also > > "No suitable machine description found" error which is done before > > legacy_serial.c code. > > > > Signed-off-by: Pali Rohár > > --- > > Tested on P2020 board. It allowed me do debug and implement this patch series: > > https://lore.kernel.org/linuxppc-dev/20220819191557.28116-1-pali@kernel.org/ > > Build failure if I select it on mpc885_ads_defconfig : > > LD vmlinux.o > MODPOST vmlinux.symvers > MODINFO modules.builtin.modinfo > GEN modules.builtin > CC .vmlinux.export.o > LD .tmp_vmlinux.kallsyms1 > powerpc64-linux-ld: arch/powerpc/kernel/udbg.o: in function > `udbg_early_init': > /home/chleroy/linux-powerpc/arch/powerpc/kernel/udbg.c:71: undefined > reference to `udbg_init_debug_16550' > > > > > --- > > arch/powerpc/Kconfig.debug | 14 ++++++++++++++ > > arch/powerpc/include/asm/udbg.h | 1 + > > arch/powerpc/kernel/udbg.c | 2 ++ > > arch/powerpc/kernel/udbg_16550.c | 33 ++++++++++++++++++++++++++++++++ > > 4 files changed, 50 insertions(+) > > > > diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug > > index 9f363c143d86..a4e7d90a45d2 100644 > > --- a/arch/powerpc/Kconfig.debug > > +++ b/arch/powerpc/Kconfig.debug > > @@ -276,6 +276,11 @@ config PPC_EARLY_DEBUG_OPAL_HVSI > > Select this to enable early debugging for the PowerNV platform > > using an "hvsi" console > > > > +config PPC_EARLY_DEBUG_16550 > > + bool "Serial 16550" > > + help > > + Select this to enable early debugging via Serial 16550 console > > + > > Putting it before EARLY_DEBUG_MEMCONS means that configs that were > previously selectiong EARLY_DEBUG_MEMCONS will now select > EARLY_DEBUG_16550 instead. > > Add a dependency to PPC_UDBG_16550 to avoid the build failure I mentionned ? Yea, there is really missing dependency. I will fix it. > > config PPC_EARLY_DEBUG_MEMCONS > > bool "In memory console" > > help > > @@ -355,6 +360,15 @@ config PPC_EARLY_DEBUG_CPM_ADDR > > platform probing is done, all platforms selected must > > share the same address. > > > > +config PPC_EARLY_DEBUG_16550_PHYSADDR > > + hex "Early debug Serial 16550 physical address" > > + depends on PPC_EARLY_DEBUG_16550 > > A default value is necessary here to avoid prompts during defconfig builds. > > > + > > +config PPC_EARLY_DEBUG_16550_STRIDE > > + int "Early debug Serial 16550 stride" > > + depends on PPC_EARLY_DEBUG_16550 > > + default 1 > > + > > config FAIL_IOMMU > > bool "Fault-injection capability for IOMMU" > > depends on FAULT_INJECTION > > diff --git a/arch/powerpc/include/asm/udbg.h b/arch/powerpc/include/asm/udbg.h > > index b4aa0d88ce2c..20b5a37ab772 100644 > > --- a/arch/powerpc/include/asm/udbg.h > > +++ b/arch/powerpc/include/asm/udbg.h > > @@ -53,6 +53,7 @@ extern void __init udbg_init_ehv_bc(void); > > extern void __init udbg_init_ps3gelic(void); > > extern void __init udbg_init_debug_opal_raw(void); > > extern void __init udbg_init_debug_opal_hvsi(void); > > +extern void __init udbg_init_debug_16550(void); > > 'extern' keywork is pointless and deprecated for function prototypes, > please don't add new ones. I used extern keyword to follow existing coding style. > Checkpatch reports: > > CHECK: extern prototypes should be avoided in .h files > #77: FILE: arch/powerpc/include/asm/udbg.h:56: > +extern void __init udbg_init_debug_16550(void); > > > > > > #endif /* __KERNEL__ */ > > #endif /* _ASM_POWERPC_UDBG_H */ > > diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c > > index b1544b2f6321..92b3fc258d11 100644 > > --- a/arch/powerpc/kernel/udbg.c > > +++ b/arch/powerpc/kernel/udbg.c > > @@ -67,6 +67,8 @@ void __init udbg_early_init(void) > > udbg_init_debug_opal_raw(); > > #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI) > > udbg_init_debug_opal_hvsi(); > > +#elif defined(CONFIG_PPC_EARLY_DEBUG_16550) > > + udbg_init_debug_16550(); > > #endif > > > > #ifdef CONFIG_PPC_EARLY_DEBUG > > diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c > > index d3942de254c6..46f2d831d7c9 100644 > > --- a/arch/powerpc/kernel/udbg_16550.c > > +++ b/arch/powerpc/kernel/udbg_16550.c > > @@ -8,6 +8,7 @@ > > #include > > #include > > #include > > +#include > > > > extern u8 real_readb(volatile u8 __iomem *addr); > > extern void real_writeb(u8 data, volatile u8 __iomem *addr); > > @@ -335,3 +336,35 @@ void __init udbg_init_debug_microwatt(void) > > } > > > > #endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ > > + > > +#ifdef CONFIG_PPC_EARLY_DEBUG_16550 > > + > > +static void __iomem *udbg_uart_early_addr; > > + > > +void __init udbg_init_debug_16550(void) > > +{ > > + udbg_uart_early_addr = early_ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > + udbg_uart_init_mmio(udbg_uart_early_addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > +} > > + > > +static int __init udbg_init_debug_16550_ioremap(void) > > +{ > > + void __iomem *addr; > > + > > + if (!udbg_uart_early_addr) > > + return 0; > > + > > + addr = ioremap(CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR, 0x1000); > > + if (WARN_ON(!addr)) > > + return -ENOMEM; > > + > > + udbg_uart_init_mmio(addr, CONFIG_PPC_EARLY_DEBUG_16550_STRIDE); > > + early_iounmap(udbg_uart_early_addr, 0x1000); > > + udbg_uart_early_addr = NULL; > > + > > + return 0; > > +} > > + > > +early_initcall(udbg_init_debug_16550_ioremap); > > + > > +#endif /* CONFIG_PPC_EARLY_DEBUG_16550 */