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

From: Shameerali Kolothum Thodi <[email-masked]>
Date: Thu, 3 Jun 2021 11:48:22 +0000

Hi Lorenzo,

> -----Original Message-----
> From: Lorenzo Pieralisi [mailto:[email-masked]]
> Sent: 03 June 2021 12:37
> To: Shameerali Kolothum Thodi <[email-masked]>
> Cc: [email-masked]; [email-masked];
> [email-masked]; Linuxarm <[email-masked]>;
> [email-masked]; [email-masked]; wanghuiqiang
> <[email-masked]>; Guohanjun (Hanjun Guo)
> <[email-masked]>; [email-masked]; [email-masked];
> [email-masked]; [email-masked]; yangyicong
> <[email-masked]>
> Subject: Re: [PATCH v4 1/8] ACPI/IORT: Add support for RMR node parsing
> 
> 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."

Ok.

Thanks for taking a look. Just a quick update, there is a v5[1] of this
series and better to take a look at that before you read further. 
(Anyways, the comments so far are still valid for v5 as well I think).

Thanks,
Shameer

[1]. https://lore.kernel.org/linux-acpi/[email-masked]/

> > Signed-off-by: Shameer Kolothum
> <[email-masked]>
> > ---
> >  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
> >

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