Re: [PATCH] pci: brcmstb: Fix build on 32bit ARM platforms with older compilers

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	Florian Fainelli <f.fainelli@gmail.com>,
	bcm-kernel-feedback-list@broadcom.com,
	Andrew Murray <amurray@thegoodpenguin.co.uk>
Subject: Re: [PATCH] pci: brcmstb: Fix build on 32bit ARM platforms with older compilers
Date: Thu, 27 Feb 2020 12:30:24 +0000	[thread overview]
Message-ID: <20200227123024.GA12798@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <20200227115146.24515-1-m.szyprowski@samsung.com>

Subject should be:

PCI: brcmstb: Fix build on 32bit ARM platforms with older compilers

On Thu, Feb 27, 2020 at 12:51:46PM +0100, Marek Szyprowski wrote:
> Some older compilers have no implementation for the helper for 64-bit
> unsigned division/modulo, so linking pcie-brcmstb driver causes the
> "undefined reference to `__aeabi_uldivmod'" error.
> 
> *rc_bar2_size is always a power of two, because it is calculated as:
> "1ULL << fls64(entry->res->end - entry->res->start)", so the modulo
> operation in the subsequent check can be replaced by a simple logical
> AND with a proper mask.
> 

Add a Fixes: tag please.

Fixes: c0452137034b ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")

> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  drivers/pci/controller/pcie-brcmstb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Hi Bjorn,

I think this should be merged in one of the upcoming -rc, given that
it fixes v5.6 material.

Here is my ACK to that end, if you prefer postponing it to v5.7
please let me know.

Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index d20aabc26273..3a10e678c7f4 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -670,7 +670,7 @@ static inline int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
>  	 *   outbound memory @ 3GB). So instead it will  start at the 1x
>  	 *   multiple of its size
>  	 */
> -	if (!*rc_bar2_size || *rc_bar2_offset % *rc_bar2_size ||
> +	if (!*rc_bar2_size || (*rc_bar2_offset & (*rc_bar2_size - 1)) ||
>  	    (*rc_bar2_offset < SZ_4G && *rc_bar2_offset > SZ_2G)) {
>  		dev_err(dev, "Invalid rc_bar2_offset/size: size 0x%llx, off 0x%llx\n",
>  			*rc_bar2_size, *rc_bar2_offset);
> -- 
> 2.17.1
> 