[PATCH v4 11/15] drivers/bus: add ARM CCI support

[Nicolas Pitre]

On Tue, 23 Apr 2013, Russell King - ARM Linux wrote:

> On Tue, Feb 05, 2013 at 12:22:08AM -0500, Nicolas Pitre wrote:
> > +void disable_cci(int cluster)
> > +{
> > +	u32 slave_reg = cluster ? CCI400_KF_OFFSET : CCI400_EAG_OFFSET;
> > +	writel_relaxed(0x0, info->baseaddr + slave_reg);
> > +
> > +	while (readl_relaxed(info->baseaddr + CCI_STATUS_OFFSET)
> > +						& STATUS_CHANGE_PENDING)
> > +			barrier();
> > +}
> > +EXPORT_SYMBOL_GPL(disable_cci);
> 
> This will blow up if the cci driver hasn't been probed - which I guess is
> fine.
> 
> > +
> > +static int cci_driver_probe(struct platform_device *pdev)
> > +{
> > +	struct resource *res;
> > +	int ret = 0;
> > +
> > +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> > +	if (!info) {
> > +		dev_err(&pdev->dev, "unable to allocate mem\n");
> > +		return -ENOMEM;
> > +	}
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	if (!res) {
> > +		dev_err(&pdev->dev, "No memory resource\n");
> > +		ret = -EINVAL;
> > +		goto mem_free;
> > +	}
> > +
> > +	if (!request_mem_region(res->start, resource_size(res),
> > +				dev_name(&pdev->dev))) {
> > +		dev_err(&pdev->dev, "address 0x%x in use\n", (u32) res->start);
> > +		ret = -EBUSY;
> > +		goto mem_free;
> > +	}
> > +
> > +	info->baseaddr = ioremap(res->start, resource_size(res));
> 
> As we are moving stuff over to the devm_* APIs, it would be a good idea to
> avoid introducing new code not using those APIs - otherwise it just creates
> yet more churn, something which Linus objects to.  Can we please try in
> future to avoid creating stuff which then needs to be subsequently modified
> for the latest ways to do stuff...

This driver is not part of the MCPM pull request.  It was provided to 
illustrate how the MCPM layer is meant to be used.  The on-going 
discussion about CPU/cluster/CCI deviice tree bindings by Lorenzo will 
significantly enhance this driver.  And given the current timing it is 
likely that the enhanced driver will simply replace this one during the 
next cycle, so we should take your comment into account.


Nicolas