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Message-ID: <20120116110907.GU1068@n2100.arm.linux.org.uk>
Date: Mon, 16 Jan 2012 11:09:07 +0000
From: Russell King - ARM Linux <linux@....linux.org.uk>
To: Jaccon Bastiaansen <jaccon.bastiaansen@...il.com>
Cc: s.hauer@...gutronix.de, kernel@...gutronix.de,
u.kleine-koenig@...gutronix.de, davem@...emloft.net,
cavokz@...il.com, netdev@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V3 1/4] CS89x0 : add platform driver support
On Sat, Jan 14, 2012 at 08:56:36PM +0100, Jaccon Bastiaansen wrote:
> The CS89x0 ethernet controller is used on a number of evaluation
> boards, such as the MX31ADS. The current driver has memory address and
> IRQ settings for each board on which this controller is used. Driver
> updates are therefore required to support other boards that also use
> the CS89x0. To avoid these driver updates, a better mechanism
> (platform driver support) is added to communicate the board dependent
> settings to the driver.
Please check your changes with sparse and checkpatch.
> @@ -236,6 +243,11 @@ struct net_local {
> unsigned char *end_dma_buff; /* points to the end of the buffer */
> unsigned char *rx_dma_ptr; /* points to the next packet */
> #endif
> +#ifdef CONFIG_CS89x0_PLATFORM
> + void *virt_addr; /* Virtual address for accessing the CS89x0. */
void __iomem *virt_addr;
> +#ifdef CONFIG_CS89x0_PLATFORM
> +static int __init cs89x0_platform_probe(struct platform_device *pdev)
> +{
> + struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
> + struct net_local *lp = netdev_priv(dev);
> + struct resource *mem_res;
> + int err;
> +
> + if (!dev)
> + return -ENODEV;
Wouldn't -ENOMEM be better? Also, organise this as:
struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
struct net_local *lp;
if (!dev)
return -ENOMEM;
lp = netdev_priv(dev);
because you don't shouldn't how netdev_priv() works, or whether it
dereferences a pointer within the net_device. (How netdev_priv()
works is not something that should concern you as a driver writer -
it's there to hide the details, which may change over time.)
> +
> + mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + dev->irq = platform_get_irq(pdev, 0);
> + if (mem_res == NULL || dev->irq <= 0) {
> + dev_warn(&dev->dev, "memory/interrupt resource missing.\n");
> + err = -ENOENT;
Other patches return -ENXIO for this.
> + goto free;
> + }
> +
> + lp->phys_addr = mem_res->start;
> + lp->size = mem_res->end - mem_res->start + 1;
lp->size = resource_size(mem_res);
> + if (!request_mem_region(lp->phys_addr, lp->size, DRV_NAME)) {
> + dev_warn(&dev->dev, "request_mem_region() failed.\n");
> + err = -ENOMEM;
If the region is busy, then this fails. It's return value should therefore
be -EBUSY.
> + goto free;
> + }
> +
> + lp->virt_addr = ioremap(lp->phys_addr, lp->size);
> + if (!lp->virt_addr) {
> + dev_warn(&dev->dev, "ioremap() failed.\n");
> + err = -ENOMEM;
> + goto release;
> + }
> +
> + err = cs89x0_probe1(dev, (int)lp->virt_addr, 0);
Have you checked whether this causes a compiler warning? Normally if you
cast a pointer to 'int', it'll complain about a narrowing cast.
There are architectures Linux supports where int is 32-bit and a pointer
is 64-bit, so this won't work. It needs the 'port' type changed to
something which pointers can be casted (I suggest unsigned long, as we
do elsewhere.)
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