Subject: Re: [PATCH] [net/irda]: new Blackfin on-chip SIR IrDA driver
From: gyang <graf.yang@analog.com>
To: Mike Frysinger <vapier.adi@gmail.com>
CC: graff yang <graff.yang@gmail.com>, samuel@sortiz.org,
       irda-users@lists.sourceforge.net, linux-kernel@vger.kernel.org,
       cooloney@kernel.org
In-Reply-To: <8bd0f97a0903112134m52a8faddp69926cb1281f5ce5@mail.gmail.com>
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	 <8bd0f97a0903110343m1f2f01catbc6cd54ecce91db9@mail.gmail.com>
	 <1236831455.21146.7.camel@dy>
	 <8bd0f97a0903112123j60eab672m16177581c959453b@mail.gmail.com>
	 <1236832241.21146.12.camel@dy>
	 <8bd0f97a0903112134m52a8faddp69926cb1281f5ce5@mail.gmail.com>
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Date: Thu, 12 Mar 2009 12:48:27 +0800
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On Thu, 2009-03-12 at 00:34 -0400, Mike Frysinger wrote:
> On Thu, Mar 12, 2009 at 00:30, gyang wrote:
> > On Thu, 2009-03-12 at 00:23 -0400, Mike Frysinger wrote:
> >> On Thu, Mar 12, 2009 at 00:17, gyang wrote:
> >> > On Wed, 2009-03-11 at 06:43 -0400, Mike Frysinger wrote:
> >> >> On Wed, Mar 11, 2009 at 05:56, graff yang wrote:
> >> >> > On Wed, Mar 11, 2009 at 3:57 PM, Mike Frysinger wrote:
> >> >> >> On Wed, Mar 11, 2009 at 03:29,  <graff.yang@gmail.com> wrote:
> >> >> >>> +static int __devinit bfin_sir_probe(struct platform_device *pdev)
> >> >> >>> +{
> >> >> >>> +       struct net_device *dev;
> >> >> >>> +       struct bfin_sir_self *self;
> >> >> >>> +       unsigned int baudrate_mask;
> >> >> >>> +       struct bfin_sir_port *sir_port;
> >> >> >>> +       int err;
> >> >> >>> +
> >> >> >>> +       err = peripheral_request_list(per[pdev->id], DRIVER_NAME);
> >> >> >>
> >> >> >> what if pdev->id is set to 12512 ?
> >> >> >
> >> >> > The pdev->id is defined in board files, for example, uart0 should be 0.
> >> >>
> >> >> so ?  what's to stop the user from setting it to 12415 ?  the driver
> >> >> must sanity check these things.  you can never assume platform dev
> >> >> resources always have valid pointers and valid values.
> >> >
> >> > How about to limit the pdev->id to be 0,1,2,3 ?
> >> > I can extend the per to be
> >> > static const unsigned short per[][4] = {
> >> >        {P_UART0_RX, P_UART0_TX, 0, 0},
> >> >        {P_UART1_RX, P_UART1_TX, 0, 1},
> >> >        {P_UART2_RX, P_UART2_TX, 0, 2},
> >> >        {P_UART3_RX, P_UART3_TX, 0, 3},
> >> > };
> >> >
> >> > then check (pdev->id >= 0 && pdev->id < ARRAY_SIZE(per) &&
> >> > per[pdev->id][3] == pdev->id)
> >>
> >> the last check is redundant.  the first two should be added.
> >
> > I'm afraid of some cases such as uart0 uses id 1, will cause driver not
> > work, and not any warning message.
> 
> then the call to peripheral request would fail as expected
For example, user want to enable irda on uart2 for bf548, he use id 0
for uart2. In these case, peripheral request may not fail, but driver
not work.

> -mike
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