Re: [PATCH v5 07/14] drivers: acpi: iort: add support for ARM SMMU platform devices creation

[Hanjun Guo <hanjun.guo@linaro.org>]

On 2016/9/13 15:46, nwatters@codeaurora.org wrote:
> On 2016-09-09 10:23, 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@arm.com>
>> Cc: Hanjun Guo <hanjun.guo@linaro.org>
>> Cc: Tomasz Nowicki <tn@semihalf.com>
>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>> ---
>>  drivers/acpi/arm64/iort.c | 131
>> ++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 131 insertions(+)
>>
>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>> index b89b3d3..e0a9b16 100644
>> --- a/drivers/acpi/arm64/iort.c
>> +++ b/drivers/acpi/arm64/iort.c
>> @@ -22,6 +22,7 @@
>>  #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 {
>> @@ -424,6 +425,135 @@ 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
>> + * @fwnode: IORT node associated fwnode handle
>> + * @node: Pointer to SMMU ACPI IORT node
>> + *
>> + * Returns: 0 on success, <0 failure
>> + */
>> +static int __init iort_add_smmu_platform_device(struct fwnode_handle
>> *fwnode,
>> +                        struct acpi_iort_node *node)
>> +{
>> +    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;
>> +
>> +    pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask),
>> GFP_KERNEL);
>> +    if (!pdev->dev.dma_mask) {
>> +        ret = -ENOMEM;
>> +        goto dev_put;
>> +    }
>> +
>> +    pdev->dev.fwnode = fwnode;
>> +
>> +    /*
>> +     * Set default dma mask value for the table walker,
>> +     * to be overridden on probing with correct value.
>> +     */
>> +    *pdev->dev.dma_mask = DMA_BIT_MASK(32);
>> +    pdev->dev.coherent_dma_mask = *pdev->dev.dma_mask;
>> +
>> +    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);
>> +    kfree(pdev->dev.dma_mask);
>> +
>> +dev_put:
>> +    platform_device_put(pdev);
>> +
>> +    return ret;
>> +}
>> +
>> +static acpi_status __init iort_match_iommu_callback(struct
>> acpi_iort_node *node,
>> +                            void *context)
>> +{
>> +    int ret;
>> +    struct fwnode_handle *fwnode;
>> +
>> +    fwnode = iort_get_fwnode(node);
>> +
>> +    if (!fwnode)
>> +        return AE_NOT_FOUND;
>> +
>> +    ret = iort_add_smmu_platform_device(fwnode, node);
>> +    if (ret) {
>> +        pr_err("Error in platform device creation\n");
>> +        return AE_ERROR;
>> +    }
>> +
>> +    return AE_OK;
>> +}
>> +
>> +static void __init iort_smmu_init(void)
>> +{
>> +    iort_scan_node(ACPI_IORT_NODE_SMMU, iort_match_iommu_callback,
>> NULL);
>> +    iort_scan_node(ACPI_IORT_NODE_SMMU_V3, iort_match_iommu_callback,
>> NULL);
>
> Since iort_scan_node() returns after the first successful match it finds,
> only the first SMMU_V3 in my IORT is being enumerated. I think you need
> to go back to the "iterator" like approach you had been using or make
> iort_match_iommu_callback() always return a non-AE_OK value so the scan
> continues and has a chance to visit all of the SMMU_V3 nodes.

Please use the updated version of IORT patch (aka Tomasz's v11)
then things will work fine.

Thanks
Hanjun