[PATCH v6 09/16] drivers: acpi: iort: add support for ARM SMMU platform devices creation

[Graeme Gregory]

On Fri, Oct 28, 2016 at 04:50:07PM +0100, Lorenzo Pieralisi wrote:
> On Tue, Oct 18, 2016 at 05:04:07PM +0100, Lorenzo Pieralisi wrote:
> > In ARM ACPI systems, IOMMU components are specified through static
> > IORT table entries. In order to create platform devices for the
> > corresponding ARM SMMU components, IORT kernel code should be made
> > able to parse IORT table entries and create platform devices
> > dynamically.
> > 
> > This patch adds the generic IORT infrastructure required to create
> > platform devices for ARM SMMUs.
> > 
> > ARM SMMU versions have different resources requirement therefore this
> > patch also introduces an IORT specific structure (ie iort_iommu_config)
> > that contains hooks (to be defined when the corresponding ARM SMMU
> > driver support is added to the kernel) to be used to define the
> > platform devices names, init the IOMMUs, count their resources and
> > finally initialize them.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> > Cc: Hanjun Guo <hanjun.guo at linaro.org>
> > Cc: Tomasz Nowicki <tn at semihalf.com>
> > Cc: "Rafael J. Wysocki" <rjw at rjwysocki.net>
> > ---
> >  drivers/acpi/arm64/iort.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 151 insertions(+)
> > 
> > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > index 1433de3..2eda2f5 100644
> > --- a/drivers/acpi/arm64/iort.c
> > +++ b/drivers/acpi/arm64/iort.c
> > @@ -19,9 +19,11 @@
> >  #define pr_fmt(fmt)	"ACPI: IORT: " fmt
> >  
> >  #include <linux/acpi_iort.h>
> > +#include <linux/iommu.h>
> >  #include <linux/kernel.h>
> >  #include <linux/list.h>
> >  #include <linux/pci.h>
> > +#include <linux/platform_device.h>
> >  #include <linux/slab.h>
> >  
> >  struct iort_its_msi_chip {
> > @@ -457,6 +459,153 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
> >  	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
> >  }
> >  
> > +struct iort_iommu_config {
> > +	const char *name;
> > +	int (*iommu_init)(struct acpi_iort_node *node);
> > +	bool (*iommu_is_coherent)(struct acpi_iort_node *node);
> > +	int (*iommu_count_resources)(struct acpi_iort_node *node);
> > +	void (*iommu_init_resources)(struct resource *res,
> > +				     struct acpi_iort_node *node);
> > +};
> > +
> > +static __init
> > +const struct iort_iommu_config *iort_get_iommu_cfg(struct acpi_iort_node *node)
> > +{
> > +	return NULL;
> > +}
> > +
> > +/**
> > + * iort_add_smmu_platform_device() - Allocate a platform device for SMMU
> > + * @node: Pointer to SMMU ACPI IORT node
> > + *
> > + * Returns: 0 on success, <0 failure
> > + */
> > +static int __init iort_add_smmu_platform_device(struct acpi_iort_node *node)
> > +{
> > +	struct fwnode_handle *fwnode;
> > +	struct platform_device *pdev;
> > +	struct resource *r;
> > +	enum dev_dma_attr attr;
> > +	int ret, count;
> > +	const struct iort_iommu_config *ops = iort_get_iommu_cfg(node);
> > +
> > +	if (!ops)
> > +		return -ENODEV;
> > +
> > +	pdev = platform_device_alloc(ops->name, PLATFORM_DEVID_AUTO);
> > +	if (!pdev)
> > +		return PTR_ERR(pdev);
> > +
> > +	count = ops->iommu_count_resources(node);
> > +
> > +	r = kcalloc(count, sizeof(*r), GFP_KERNEL);
> > +	if (!r) {
> > +		ret = -ENOMEM;
> > +		goto dev_put;
> > +	}
> > +
> > +	ops->iommu_init_resources(r, node);
> > +
> > +	ret = platform_device_add_resources(pdev, r, count);
> > +	/*
> > +	 * Resources are duplicated in platform_device_add_resources,
> > +	 * free their allocated memory
> > +	 */
> > +	kfree(r);
> > +
> > +	if (ret)
> > +		goto dev_put;
> > +
> > +	/*
> > +	 * Add a copy of IORT node pointer to platform_data to
> > +	 * be used to retrieve IORT data information.
> > +	 */
> > +	ret = platform_device_add_data(pdev, &node, sizeof(node));
> > +	if (ret)
> > +		goto dev_put;
> > +
> > +	/*
> > +	 * We expect the dma masks to be equivalent for
> > +	 * all SMMUs set-ups
> > +	 */
> > +	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
> > +
> > +	fwnode = iort_get_fwnode(node);
> > +
> > +	if (!fwnode) {
> > +		ret = -ENODEV;
> > +		goto dev_put;
> > +	}
> > +
> > +	pdev->dev.fwnode = fwnode;
> > +
> > +	attr = ops->iommu_is_coherent(node) ?
> > +			     DEV_DMA_COHERENT : DEV_DMA_NON_COHERENT;
> > +
> > +	/* Configure DMA for the page table walker */
> > +	acpi_dma_configure(&pdev->dev, attr);
> > +
> > +	ret = platform_device_add(pdev);
> > +	if (ret)
> > +		goto dma_deconfigure;
> > +
> > +	return 0;
> > +
> > +dma_deconfigure:
> > +	acpi_dma_deconfigure(&pdev->dev);
> > +dev_put:
> > +	platform_device_put(pdev);
> > +
> > +	return ret;
> > +}
> > +
> > +static void __init iort_init_platform_devices(void)
> > +{
> > +	struct acpi_iort_node *iort_node, *iort_end;
> > +	struct acpi_table_iort *iort;
> > +	struct fwnode_handle *fwnode;
> > +	int i, ret;
> > +
> > +	/*
> > +	 * iort_table and iort both point to the start of IORT table, but
> > +	 * have different struct types
> > +	 */
> > +	iort = (struct acpi_table_iort *)iort_table;
> > +
> > +	/* Get the first IORT node */
> > +	iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
> > +				 iort->node_offset);
> > +	iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort,
> > +				iort_table->length);
> > +
> > +	for (i = 0; i < iort->node_count; i++) {
> > +		if (iort_node >= iort_end) {
> > +			pr_err("iort node pointer overflows, bad table\n");
> > +			return;
> > +		}
> > +
> > +		if ((iort_node->type == ACPI_IORT_NODE_SMMU) ||
> > +			(iort_node->type == ACPI_IORT_NODE_SMMU_V3)) {
> > +
> > +			fwnode = acpi_alloc_fwnode_static();
> > +			if (!fwnode)
> > +				return;
> > +
> > +			iort_set_fwnode(iort_node, fwnode);
> > +
> > +			ret = iort_add_smmu_platform_device(iort_node);
> > +			if (ret) {
> > +				iort_delete_fwnode(iort_node);
> > +				acpi_free_fwnode_static(fwnode);
> > +				return;
> > +			}
> > +		}
> > +
> > +		iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
> > +					 iort_node->length);
> > +	}
> > +}
> > +
> >  void __init acpi_iort_init(void)
> >  {
> >  	acpi_status status;
> > @@ -468,5 +617,7 @@ void __init acpi_iort_init(void)
> >  		return;
> >  	}
> >  
> 
> Slipped through the cracks while rebasing v6, I should add code that
> returns if no IORT table found here to prevent calling:
> 
> iort_init_platform_devices()
> 
> I will update the next version, it is just a heads-up for testers,
> I can push an updated/fixed branch if needed.
> 

I could do with the updated branch.

Thanks

Graeme