Re: [PATCH] imx: Provide correct number of resources when registering gpio devices

[Bjorn Helgaas]

On Tue, Jun 30, 2020 at 08:26:51PM -0700, Guenter Roeck wrote:
> Since commit a85a6c86c25be ("driver core: platform: Clarify that IRQ 0 is
> invalid"), the kernel is a bit touchy when it encounters interrupt 0.
> As a result, there are lots of warnings such as the following when booting
> systems such as 'kzm'.

Thanks for the fix.  If there are others like this, I'd be glad to
help fix them since I made the kernel grumpier about this.  Just point
me at the info.

I looked at other callers of platform_device_register_resndata().  It
looks like imx_add_imx_dma() and vm_cmdline_set() have the same
problem.  I'll fix those unless you're already doing it.

> WARNING: CPU: 0 PID: 1 at drivers/base/platform.c:224 platform_get_irq_optional+0x118/0x128
> 0 is an invalid IRQ number
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3 #1
> Hardware name: Kyoto Microcomputer Co., Ltd. KZM-ARM11-01
> [<c01127d4>] (unwind_backtrace) from [<c010c620>] (show_stack+0x10/0x14)
> [<c010c620>] (show_stack) from [<c06f5f54>] (dump_stack+0xe8/0x120)
> [<c06f5f54>] (dump_stack) from [<c0128878>] (__warn+0xe4/0x108)
> [<c0128878>] (__warn) from [<c0128910>] (warn_slowpath_fmt+0x74/0xbc)
> [<c0128910>] (warn_slowpath_fmt) from [<c08b8e84>] (platform_get_irq_optional+0x118/0x128)
> [<c08b8e84>] (platform_get_irq_optional) from [<c08b8eb4>] (platform_irq_count+0x20/0x3c)
> [<c08b8eb4>] (platform_irq_count) from [<c0728660>] (mxc_gpio_probe+0x8c/0x494)
> [<c0728660>] (mxc_gpio_probe) from [<c08b93cc>] (platform_drv_probe+0x48/0x98)
> [<c08b93cc>] (platform_drv_probe) from [<c08b703c>] (really_probe+0x214/0x344)
> [<c08b703c>] (really_probe) from [<c08b7274>] (driver_probe_device+0x58/0xb4)
> [<c08b7274>] (driver_probe_device) from [<c08b7478>] (device_driver_attach+0x58/0x60)
> [<c08b7478>] (device_driver_attach) from [<c08b7504>] (__driver_attach+0x84/0xc0)
> [<c08b7504>] (__driver_attach) from [<c08b50f8>] (bus_for_each_dev+0x78/0xb8)
> [<c08b50f8>] (bus_for_each_dev) from [<c08b62cc>] (bus_add_driver+0x154/0x1e0)
> [<c08b62cc>] (bus_add_driver) from [<c08b82b8>] (driver_register+0x74/0x108)
> [<c08b82b8>] (driver_register) from [<c0102320>] (do_one_initcall+0x80/0x3b4)
> [<c0102320>] (do_one_initcall) from [<c1501008>] (kernel_init_freeable+0x170/0x208)
> [<c1501008>] (kernel_init_freeable) from [<c0e178d4>] (kernel_init+0x8/0x11c)
> [<c0e178d4>] (kernel_init) from [<c0100134>] (ret_from_fork+0x14/0x20)
> 
> As it turns out, mxc_register_gpio() is a bit lax when setting the
> number of resources: it registers a resource with interrupt 0 when in
> reality there is no such interrupt. Fix the problem by not declaring
> the second interrupt resource if there is no second interrupt.
> 
> Fixes: a85a6c86c25be ("driver core: platform: Clarify that IRQ 0 is invalid")
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
>  arch/arm/mach-imx/devices/platform-gpio-mxc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/devices/platform-gpio-mxc.c b/arch/arm/mach-imx/devices/platform-gpio-mxc.c
> index 78628ef12672..355de845224c 100644
> --- a/arch/arm/mach-imx/devices/platform-gpio-mxc.c
> +++ b/arch/arm/mach-imx/devices/platform-gpio-mxc.c
> @@ -24,7 +24,8 @@ struct platform_device *__init mxc_register_gpio(char *name, int id,
>  			.flags = IORESOURCE_IRQ,
>  		},
>  	};
> +	unsigned int nres;
>  
> -	return platform_device_register_resndata(&mxc_aips_bus,
> -			name, id, res, ARRAY_SIZE(res), NULL, 0);
> +	nres = irq_high ? ARRAY_SIZE(res) : ARRAY_SIZE(res) - 1;
> +	return platform_device_register_resndata(&mxc_aips_bus, name, id, res, nres, NULL, 0);
>  }
> -- 
> 2.17.1
>