linux-kernel - Re: [PATCH] PCI: iproc: fix 32-bit build error

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Message-ID: <561D6576.2020107@broadcom.com>
Date:	Tue, 13 Oct 2015 13:11:34 -0700
From:	Ray Jui <rjui@...adcom.com>
To:	Hauke Mehrtens <hauke@...ke-m.de>, Arnd Bergmann <arnd@...db.de>,
	<linux-arm-kernel@...ts.infradead.org>
CC:	Kevin Hilman <khilman@...nel.org>,
	Tyler Baker <tyler.baker@...aro.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Olof Johansson <olof@...om.net>,
	"Mark Brown" <broonie@...nel.org>,
	<bcm-kernel-feedback-list@...adcom.com>,
	"Linux PCI" <linux-pci@...r.kernel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] PCI: iproc: fix 32-bit build error



On 10/13/2015 1:06 PM, Hauke Mehrtens wrote:
> On 10/13/2015 10:02 PM, Arnd Bergmann wrote:
>> The iproc PCI driver tries to figure out whether the MMIO window has
>> a valid size, but does this using a 64-bit modulo operation, which
>> is not allowed on 32-bit kernels and leads to a link error:
>>
>> drivers/built-in.o: In function `iproc_pcie_setup':
>> :(.text+0x4b798): undefined reference to `__aeabi_uldivmod'
>>
>> This works around that error by using the div64_u64() function
>> provided by the kernel. While this is an expensive operation,
>> it is harmless because we only call it during the probing
>> of the driver.
>>

Thanks, Arnd. Guess I did not see this issue when running on ARM32 based
platforms like Cygnus, because LAPE was not enabled by default for
multi_v7_defconfig. When LAPE is enabled, resource_size_t becomes 64-bit.

>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>> Fixes: 0ab99ca8eb6c ("PCI: iproc: Fix compile warnings")
>>
>> diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
>> index f3481ddff344..abcb4be2ee19 100644
>> --- a/drivers/pci/host/pcie-iproc.c
>> +++ b/drivers/pci/host/pcie-iproc.c
>> @@ -235,12 +235,13 @@ static void iproc_pcie_enable(struct iproc_pcie *pcie)
>>   *
>>   * axi_addr -> iproc_pcie_address -> OARR -> OMAP -> pci_address
>>   */
>> -static int iproc_pcie_setup_ob(struct iproc_pcie *pcie, u64 axi_addr,
>> +int iproc_pcie_setup_ob(struct iproc_pcie *pcie, u64 axi_addr,
> 
> Why are you removing the static here?
> 

Yeah we should keep this function as static. The rest of this change
looks good!

>>  			       u64 pci_addr, resource_size_t size)
>>  {
>>  	struct iproc_pcie_ob *ob = &pcie->ob;
>>  	unsigned i;
>>  	u64 max_size = (u64)ob->window_size * MAX_NUM_OB_WINDOWS;
>> +	u64 remainder;
>>  
>>  	if (size > max_size) {
>>  		dev_err(pcie->dev,
>> @@ -249,7 +250,8 @@ static int iproc_pcie_setup_ob(struct iproc_pcie *pcie, u64 axi_addr,
>>  		return -EINVAL;
>>  	}
>>  
>> -	if (size % ob->window_size) {
>> +	div64_u64_rem(size, ob->window_size, &remainder);
>> +	if (remainder) {
>>  		dev_err(pcie->dev,
>>  			"res size %pap needs to be multiple of window size %pap\n",
>>  			&size, &ob->window_size);
>>
> 

Thanks,

Ray
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