From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH] pl011: early_panic if baud rate not set in hardware Date: Thu, 22 Aug 2013 17:34:20 +0100 Message-ID: <52163D8C.5050404@linaro.org> References: <1377187319-30598-1-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1377187319-30598-1-git-send-email-ian.campbell@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: stefano.stabellini@eu.citrix.com, tim@xen.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 08/22/2013 05:01 PM, Ian Campbell wrote: > Now that the driver defaults to BAUD_AUTO this can happen if the early uart != > console or if early printk isn't in use. Does the fast model set correctly the baud rate? > The following division by zero causes a trap but that uses regular printk and > not early_printk, so it is never seen. That's annoying. I often have this problem, is there any plan to support early print in printk? > Signed-off-by: Ian Campbell Acked-by: Julien Grall > --- > xen/drivers/char/pl011.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c > index 0e1eb64..7eb90b0 100644 > --- a/xen/drivers/char/pl011.c > +++ b/xen/drivers/char/pl011.c > @@ -104,6 +104,8 @@ static void __init pl011_init_preirq(struct serial_port *port) > { > /* Baud rate already set: read it out from the divisor latch. */ > divisor = (pl011_read(uart, IBRD) << 6) | (pl011_read(uart, FBRD)); > + if (!divisor) > + early_panic("pl011: No Baud rate configured\n"); > uart->baud = (uart->clock_hz << 2) / divisor; > } > /* This write must follow FBRD and IBRD writes. */ > -- Julien Grall