From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Tcvgx-0001UB-SV for barebox@lists.infradead.org; Mon, 26 Nov 2012 10:13:32 +0000 From: Sascha Hauer Date: Mon, 26 Nov 2012 11:13:26 +0100 Message-Id: <1353924807-519-2-git-send-email-s.hauer@pengutronix.de> In-Reply-To: <1353924807-519-1-git-send-email-s.hauer@pengutronix.de> References: <1353924807-519-1-git-send-email-s.hauer@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 2/3] debug_ll: Add some usage comments To: barebox@lists.infradead.org Signed-off-by: Sascha Hauer --- common/Kconfig | 2 ++ include/debug_ll.h | 16 +++++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/common/Kconfig b/common/Kconfig index d60db80..57119dc 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -667,6 +667,8 @@ config DEBUG_LL prompt "low level debug messages" help Enable this to get low level debug messages during barebox initialization. + This requires SoC specific support. Most SoCs require the debug UART to be + initialized by a debugger or first stage bootloader. endmenu diff --git a/include/debug_ll.h b/include/debug_ll.h index c5f2df4..f0034ba 100644 --- a/include/debug_ll.h +++ b/include/debug_ll.h @@ -1,4 +1,5 @@ -/* debug_ll.h +/* + * debug_ll.h * * written by Marc Singer * 12 Feb 2005 @@ -20,6 +21,14 @@ #define __INCLUDE_DEBUG_LL_H__ #if defined (CONFIG_DEBUG_LL) + +/* + * mach/debug_ll.h should implement PUTC_LL. This can be a macro or a static + * inline function. Note that several SoCs expect the UART to be initialized + * by a debugger or a first stage bootloader. You won't see anything without + * this initialization. Depending on the PUTC_LL implementation the board might + * also hang in PUTC_LL without proper initialization. + */ # include # define PUTHEX_LL(value) ({ unsigned long v = (unsigned long) (value); \ @@ -29,6 +38,11 @@ ch += (ch >= 10) ? 'a' - 10 : '0';\ PUTC_LL (ch); }}) +/* + * Be careful with PUTS_LL, it only works if the binary is running at the + * link address which often is not the case during early startup. If in doubt + * don't use it. + */ static __inline__ void PUTS_LL(const char * str) { while (*str) { -- 1.7.10.4 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox