Re: [PATCH v4 1/8] ACPI/IORT: Add support for RMR node parsing

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Thu, May 13, 2021 at 02:45:43PM +0100, Shameer Kolothum wrote:
> Add support for parsing RMR node information from ACPI.
> Find associated stream id and smmu node info from the
> RMR node and populate a linked list with RMR memory
> descriptors.

"Add support for parsing RMR node information from ACPI.

Find the associated streamid and SMMU node info from the
RMR node and populate a linked list with RMR memory
descriptors."

> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/acpi/arm64/iort.c | 104 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 103 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 3912a1f6058e..fea1ffaedf3b 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -40,6 +40,19 @@ struct iort_fwnode {
>  static LIST_HEAD(iort_fwnode_list);
>  static DEFINE_SPINLOCK(iort_fwnode_lock);
>  
> +/*
> + * One entry for IORT RMR.
> + */
> +struct iort_rmr_entry {
> +	struct list_head list;
> +	u32 sid;
> +	struct acpi_iort_node *smmu;
> +	struct acpi_iort_rmr_desc *rmr_desc;
> +	u32 flags;
> +};
> +
> +static LIST_HEAD(iort_rmr_list);         /* list of RMR regions from ACPI */
> +
>  /**
>   * iort_set_fwnode() - Create iort_fwnode and use it to register
>   *		       iommu data in the iort_fwnode_list
> @@ -393,7 +406,8 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
>  		if (node->type == ACPI_IORT_NODE_NAMED_COMPONENT ||
>  		    node->type == ACPI_IORT_NODE_PCI_ROOT_COMPLEX ||
>  		    node->type == ACPI_IORT_NODE_SMMU_V3 ||
> -		    node->type == ACPI_IORT_NODE_PMCG) {
> +		    node->type == ACPI_IORT_NODE_PMCG ||
> +		    node->type == ACPI_IORT_NODE_RMR) {
>  			*id_out = map->output_base;
>  			return parent;
>  		}
> @@ -1660,6 +1674,91 @@ static void __init iort_enable_acs(struct acpi_iort_node *iort_node)
>  #else
>  static inline void iort_enable_acs(struct acpi_iort_node *iort_node) { }
>  #endif
> +static int iort_rmr_desc_valid(struct acpi_iort_rmr_desc *desc, u32 count)
> +{
> +	int i, j;
> +
> +	for (i = 0; i < count; i++) {
> +		u64 end, start = desc[i].base_address, length = desc[i].length;
> +
> +		if (!IS_ALIGNED(start, SZ_64K) || !IS_ALIGNED(length, SZ_64K))
> +			return -EINVAL;
> +
> +		end = start + length - 1;
> +
> +		/* Check for address overlap */
> +		for (j = i + 1; j < count; j++) {
> +			u64 e_start = desc[j].base_address;
> +			u64 e_end = e_start + desc[j].length - 1;
> +
> +			if (start <= e_end && end >= e_start)
> +				return -EINVAL;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int __init iort_parse_rmr(struct acpi_iort_node *iort_node)
> +{
> +	struct acpi_iort_node *smmu;
> +	struct iort_rmr_entry *e;
> +	struct acpi_iort_rmr *rmr;
> +	struct acpi_iort_rmr_desc *rmr_desc;
> +	u32 map_count = iort_node->mapping_count;
> +	u32  sid;
           ^
Remove one space.

> +	int i, ret = 0;
> +
> +	if (iort_node->type != ACPI_IORT_NODE_RMR)
> +		return 0;
> +
> +	if (!iort_node->mapping_offset || map_count != 1) {
> +		pr_err(FW_BUG "Invalid ID mapping, skipping RMR node %p\n",
> +		       iort_node);
> +		return -EINVAL;
> +	}
> +
> +	/* Retrieve associated smmu and stream id */
> +	smmu = iort_node_get_id(iort_node, &sid, 0);
> +	if (!smmu) {
> +		pr_err(FW_BUG "Invalid SMMU reference, skipping RMR node %p\n",
> +		       iort_node);
> +		return -EINVAL;
> +	}
> +
> +	/* Retrieve RMR data */
> +	rmr = (struct acpi_iort_rmr *)iort_node->node_data;
> +	if (!rmr->rmr_offset || !rmr->rmr_count) {
> +		pr_err(FW_BUG "Invalid RMR descriptor array, skipping RMR node %p\n",
> +		       iort_node);
> +		return -EINVAL;
> +	}
> +
> +	rmr_desc = ACPI_ADD_PTR(struct acpi_iort_rmr_desc, iort_node,
> +				rmr->rmr_offset);
> +
> +	ret = iort_rmr_desc_valid(rmr_desc, rmr->rmr_count);
> +	if (ret) {
> +		pr_err(FW_BUG "Invalid RMR descriptor[%d] for node %p, skipping...\n",
> +		       i, iort_node);
> +		return ret;
> +	}
> +
> +	for (i = 0; i < rmr->rmr_count; i++, rmr_desc++) {
> +		e = kmalloc(sizeof(*e), GFP_KERNEL);
> +		if (!e)
> +			return -ENOMEM;
> +
> +		e->sid = sid;
> +		e->smmu = smmu;
> +		e->rmr_desc = rmr_desc;
> +		e->flags = rmr->flags;
> +
> +		list_add_tail(&e->list, &iort_rmr_list);
> +	}
> +
> +	return 0;
> +}
>  
>  static void __init iort_init_platform_devices(void)
>  {
> @@ -1689,6 +1788,9 @@ static void __init iort_init_platform_devices(void)
>  
>  		iort_enable_acs(iort_node);
>  
> +		if (iort_table->revision == 3)
> +			iort_parse_rmr(iort_node);
> +

I prefer creating a iort_parse_rmr(void) function (looping through the
nodes and only parsing the relevant ones) rather that doing this in:

iort_init_platform_devices()

it is better IMO.

Thanks,
Lorenzo

>  		ops = iort_get_dev_cfg(iort_node);
>  		if (ops) {
>  			fwnode = acpi_alloc_fwnode_static();
> -- 
> 2.17.1
>