Re: [PATCH] iommu: silence iommu group prints

[Russell King - ARM Linux admin <linux@armlinux.org.uk>]

On Tue, Mar 03, 2020 at 05:55:05PM +0200, Laurentiu Tudor wrote:
> From c98dc05cdd45ae923654f2427985bd28bcde4bb2 Mon Sep 17 00:00:00 2001
> From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Date: Thu, 13 Feb 2020 11:59:12 +0200
> Subject: [PATCH 1/4] bus: fsl-mc: add custom .dma_configure implementation
> Content-Type: text/plain; charset="us-ascii"
> 
> The devices on this bus are not discovered by way of device tree
> but by queries to the firmware. It makes little sense to trick the
> generic of layer into thinking that these devices are of related so
> that we can get our dma configuration. Instead of doing that, add
> our custom dma configuration implementation.

Firstly, applying this to v5.5 results in a build failure, due to a
missing linux/iommu.h include.

Secondly, this on its own appears to make the DPAA2 network interfaces
completely disappear.  Looking in /sys/bus/fsl-mc/drivers/*, none of
the DPAA2 drivers are bound to anything, and looking in
/sys/bus/fsl-mc/devices/, there is:

lrwxrwxrwx 1 root root 0 Mar  3 22:06 dprc.1 -> ../../../devices/platform/soc/80c000000.fsl-mc/dprc.1

This is booting with u-boot, so using DT rather than ACPI.

> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> ---
>  drivers/bus/fsl-mc/fsl-mc-bus.c | 42 ++++++++++++++++++++++++++++++++-
>  1 file changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
> index 36eb25f82c8e..3df015eedae4 100644
> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
> @@ -132,11 +132,51 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
>  static int fsl_mc_dma_configure(struct device *dev)
>  {
>  	struct device *dma_dev = dev;
> +	struct iommu_fwspec *fwspec;
> +	const struct iommu_ops *iommu_ops;
> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
> +	int ret;
> +	u32 icid;
> +
> +	/* Skip DMA setup for devices that are not DMA masters */
> +	if (dev->type == &fsl_mc_bus_dpmcp_type ||
> +	    dev->type == &fsl_mc_bus_dpbp_type ||
> +	    dev->type == &fsl_mc_bus_dpcon_type ||
> +	    dev->type == &fsl_mc_bus_dpio_type)
> +		return 0;
>  
>  	while (dev_is_fsl_mc(dma_dev))
>  		dma_dev = dma_dev->parent;
>  
> -	return of_dma_configure(dev, dma_dev->of_node, 0);
> +	fwspec = dev_iommu_fwspec_get(dma_dev);
> +	if (!fwspec)
> +		return -ENODEV;

The problem appears to be here - fwspec is NULL for dprc.1.

> +	iommu_ops = iommu_ops_from_fwnode(fwspec->iommu_fwnode);
> +	if (!iommu_ops)
> +		return -ENODEV;
> +
> +	ret = iommu_fwspec_init(dev, fwspec->iommu_fwnode, iommu_ops);
> +	if (ret)
> +		return ret;
> +
> +	icid = mc_dev->icid;
> +	ret = iommu_fwspec_add_ids(dev, &icid, 1);
> +	if (ret) {
> +		iommu_fwspec_free(dev);
> +		return ret;
> +	}
> +
> +	if (!device_iommu_mapped(dev)) {
> +		ret = iommu_probe_device(dev);
> +		if (ret) {
> +			iommu_fwspec_free(dev);
> +			return ret;
> +		}
> +	}
> +
> +	arch_setup_dma_ops(dev, 0, *dma_dev->dma_mask + 1, iommu_ops, true);
> +
> +	return 0;
>  }
>  
>  static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
> -- 
> 2.17.1
> 


-- 
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