Re: [PATCH] powerpc/pseries/iommu: export DMA window data to user space

[Gaurav Batra <gbatra@linux.ibm.com>]

Hello Vaibhav/Shiva,


Thanks a lot for taking time to review the patch and for 
comments/suggestions. I have incorporated the changes. Will be sending 
out V2.


Gaurav

On 3/13/26 11:38 AM, Vaibhav Jain wrote:
> Hi Gaurav,
>
> Thanks for the patch. Few review comments inline below:
>
> Gaurav Batra <gbatra@linux.ibm.com> writes:
>
>> Export PowerPC DMA window information (both default 2GB and Dynamic
>> larger window) to user space via sysfs. Each of these DMA windows has
>> attributes like size of the window, page size backing the window, mode,
>> etc. Each of these atributes is exported for user space consumption as a
>> file.
>>
>> PowerPC Host Bridge (PHB) can have multiple devices/functions sharing
>> the same DMA window. For each PHB, iommu registration creates an iommu
>> device under "/sys/devices/virtual/iommu".
>>
>> These devices will have 2 groups created to export Default and DDW
>> attributes.
>>
>> Reviewed-by: Brian King <brking@linux.ibm.com>
>> Signed-off-by: Gaurav Batra <gbatra@linux.ibm.com>
>> ---
>>   .../arch/powerpc/dma_window_attributes.rst    |  65 +++++
>>   arch/powerpc/include/asm/iommu.h              |  20 ++
>>   arch/powerpc/kernel/iommu.c                   | 235 ++++++++++++++++++
>>   arch/powerpc/platforms/pseries/iommu.c        | 156 ++++++++++++
>>   4 files changed, 476 insertions(+)
>>   create mode 100644 Documentation/arch/powerpc/dma_window_attributes.rst
>>
>> diff --git a/Documentation/arch/powerpc/dma_window_attributes.rst b/Documentation/arch/powerpc/dma_window_attributes.rst
>> new file mode 100644
>> index 000000000000..8bd9aec8539d
>> --- /dev/null
>> +++ b/Documentation/arch/powerpc/dma_window_attributes.rst
>> @@ -0,0 +1,65 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +=====================
>> +DMA Window Attributes
>> +=====================
>> +
>> +In PowerPC architecture there are 2 types of DMA windows -
>> +
>> +1. Default 2GB DMA window which is backed by 4K page size
>> +2. A bigger Dynamic DMA Window (DDW) which is backed by larger page size
>> +   (64K or 2MB)
>> +
>> +A dedicated device will have both the DMA windows instantiated but an SR-IOV
>> +device will only have the bigger Dynamic DMA Window.
>> +
>> +The attributes of these 2 DMA windows are exported to user space via sysfs.
>> +Each IOMMU isolation unit will have its directory created under
>> +/sys/devices/virtual/iommu.
>> +
>> +As an exapmple, iommu-phb0001
>> +
>> +Under each IOMMU isolation unit, there will be a group of attributes for
>> +"Default 2GB DMA Window" and "Dynamic DMA Window" - spapr-tce-dma and
>> +spapr-tce-ddw respectively.
>> +
>> +Attributes under each group
>> +
>> +spapr-tce-ddw:
>> +direct_address  dynamic_address       dynamic_size  window_type
>> +direct_size     dynamic_pages_mapped  page_size
>> +
>> +spapr-tce-dma:
>> +dynamic_address  dynamic_pages_mapped  dynamic_size  page_size
>> +
>> +
>> +The bigger Dynamic DMA Window is configured into pre-mapped and/or dynamically
>> +allocated TCEs. If the DDW is in "Hybrid" mode, then both the Direct
>> +(pre-mapped) and Dynamic part of the DMA window will have valid values. Hybrid
>> +mode is valid only for SR-IOV devices.
>> +
>> +DMA Window properties:
>> +
>> +direct_address              Starting address of the pre-mapped DMA window
>> +direct_size                 Size of the pre-mapped DMA Window
>> +dynamic_address             Starting address of the dynamic allocations
>> +dynamic_size                Size of the dynamic allocation window
>> +dynamic_pages_mapped        Pages mapped for DMA by dynamic allocations
>> +page_size                   Page size backing the DMA window
>> +window_type                 Type of the DMA Window (Direct/Dynamic/Hybrid)
>> +
>> +
>> +An example of DDW attributes for an SR-IOV device::
>> +
>> +    $ cd /sys/devices/virtual/iommu/iommu-phb0001/spapr-tce-ddw
>> +
>> +    $ grep . *
>> +
>> +    direct_address:0x800000000000000   <-- Starting addr of pre-mapped Window
>> +    direct_size:137438953472           <-- Size of pre-mapped Window (128GB)
>> +    dynamic_address:0x800002000000000  <-- Starting addr of Dynamic allocations
>> +    dynamic_size:412316860416          <-- Size of dynamic allocation window (384GB)
>> +    dynamic_pages_mapped:270           <-- Pages mapped by dynamic allocations
>> +    page_size:2097152                  <-- DMA window page size (2MB)
>> +    window_type:Hybrid                 <-- window has both pre-mapped and
>> +                                           dynamic sections
> Since sysfs is ABI can you propose appropriate entries under Documentation/ABI/testing
>
>> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
>> index eafdd63cd6c4..e644c6e95301 100644
>> --- a/arch/powerpc/include/asm/iommu.h
>> +++ b/arch/powerpc/include/asm/iommu.h
>> @@ -90,6 +90,7 @@ struct iommu_pool {
>>   	unsigned long start;
>>   	unsigned long end;
>>   	unsigned long hint;
>> +	unsigned long inuse;
>>   	spinlock_t lock;
>>   } ____cacheline_aligned_in_smp;
>>
> Review-comment from Shivaprasad:
> Instead of  maintaining a counter in iommu_pool can you just 'weigh' the it_map
> bitmap. That way you wont have to introduce a new counter. Please look
> into how iommu_debugfs_weight_get() does this.
>
>
>> @@ -319,5 +320,24 @@ extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
>>   
>>   extern const struct dma_map_ops dma_iommu_ops;
>>   
>> +/* used by sysfs when querying Dynamic/Default DMA Window data */
>> +struct dma_win_data {
>> +	u32     win_pgsize;
>> +	u64     direct_addr;
>> +	u64     direct_size;
>> +	u64     dynamic_addr;
>> +	u64     dynamic_size;
>> +	u32     dynamic_tces_inuse;
>> +	char    win_type[15];
>> +};
>> +
>> +#define SPAPR_SUCCESS       0
>> +#define SPAPR_NODMAWIN      -1
>> +#define SPAPR_NODDWWIN      -2
>> +#define SPAPR_ERROR         -3
>> +
>> +extern int gather_ddw_info(struct device *dev, struct dma_win_data *data);
>> +extern int gather_dma_info(struct device *dev, struct dma_win_data *data);
>> +
>>   #endif /* __KERNEL__ */
>>   #endif /* _ASM_IOMMU_H */
>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
>> index 0ce71310b7d9..e3cf3701dd6e 100644
>> --- a/arch/powerpc/kernel/iommu.c
>> +++ b/arch/powerpc/kernel/iommu.c
>> @@ -339,6 +339,9 @@ static unsigned long iommu_range_alloc(struct device *dev,
>>   	if (handle)
>>   		*handle = end;
>>   
>> +	/* update use count */
>> +	pool->inuse += npages;
>> +
> See the review comment above. This counter can be done away with.
>
>>   	spin_unlock_irqrestore(&(pool->lock), flags);
>>   
>>   	return n;
>> @@ -452,6 +455,7 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
>>   	tbl->it_ops->clear(tbl, entry, npages);
>>   
>>   	spin_lock_irqsave(&(pool->lock), flags);
>> +	pool->inuse -= npages;
> Ditto as above
>
>>   	bitmap_clear(tbl->it_map, free_entry, npages);
>>   	spin_unlock_irqrestore(&(pool->lock), flags);
>>   }
>> @@ -759,6 +763,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid,
>>   		p->start = tbl->poolsize * i;
>>   		p->hint = p->start;
>>   		p->end = p->start + tbl->poolsize;
>> +		p->inuse = 0;
> Ditto as above
>
>>   	}
>>   
>>   	p = &tbl->large_pool;
>> @@ -766,6 +771,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid,
>>   	p->start = tbl->poolsize * i;
>>   	p->hint = p->start;
>>   	p->end = tbl->it_size;
>> +	p->inuse = 0;
>>   
>>   	iommu_table_clear(tbl);
>>   
>> @@ -1269,6 +1275,233 @@ static const struct iommu_ops spapr_tce_iommu_ops = {
>>   	.device_group = spapr_tce_iommu_device_group,
>>   };
>>   
>> +static inline const char *dma_win_error(int err)
>> +{
>> +	switch (err) {
>> +	case SPAPR_ERROR:
>> +		return "Error";
>> +	case SPAPR_NODMAWIN:
>> +		return "No Default DMA Window Found";
>> +	case SPAPR_NODDWWIN:
>> +		return "No Dynamic DMA Window Found";
>> +	default:
>> +		return "Unknown Result";
>> +	}
>> +}
>> +
>> +static ssize_t ddw_direct_address_show(struct device *dev,
>> +									   struct device_attribute *attr,
>> +									   char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%#llx\n", data.direct_addr);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
> Instead of returning success from these *_show() functions despite dma
> window not available, can you just return an error (e.g ENOENT) so that
> userspace know the error instantly instead of having to parse the sysfs
> contents.
>
>
>
>> +static ssize_t ddw_dynamic_address_show(struct device *dev,
>> +										struct device_attribute *attr,
>> +										char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%#llx\n", data.dynamic_addr);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t ddw_direct_size_show(struct device *dev,
>> +									struct device_attribute *attr,
>> +									char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%lld\n", data.direct_size);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t ddw_dynamic_size_show(struct device *dev,
>> +									 struct device_attribute *attr,
>> +									 char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%lld\n", data.dynamic_size);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t ddw_page_size_show(struct device *dev,
>> +								  struct device_attribute *attr,
>> +								  char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%d\n", data.win_pgsize);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t ddw_window_type_show(struct device *dev,
>> +									struct device_attribute *attr,
>> +									char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%s\n", data.win_type);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t ddw_dynamic_pages_mapped_show(struct device *dev,
>> +											 struct device_attribute *attr,
>> +											 char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_ddw_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%d\n", data.dynamic_tces_inuse);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t dma_dynamic_address_show(struct device *dev,
>> +										struct device_attribute *attr,
>> +										char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_dma_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%#llx\n", data.dynamic_addr);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t dma_dynamic_size_show(struct device *dev,
>> +									 struct device_attribute *attr,
>> +									 char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_dma_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%lld\n", data.dynamic_size);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t dma_page_size_show(struct device *dev,
>> +								  struct device_attribute *attr,
>> +								  char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_dma_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%d\n", data.win_pgsize);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
>> +
>> +static ssize_t dma_dynamic_pages_mapped_show(struct device *dev,
>> +											 struct device_attribute *attr,
>> +											 char *buf)
>> +{
>> +	int rc = 0;
>> +	struct dma_win_data data;
>> +
>> +	rc = gather_dma_info(dev, &data);
>> +
>> +	if (rc == SPAPR_SUCCESS)
>> +		return sysfs_emit(buf, "%d\n", data.dynamic_tces_inuse);
>> +	else
>> +		return sysfs_emit(buf, "%s\n", dma_win_error(rc));
>> +}
> All the *_show() functions above share same template. Please convert
> them to macros expansion below to reduce code volume.
>
>
>> +
>> +#define DEVICE_ATTR_DDW(_name)                              \
>> +		struct device_attribute dev_attr_ddw_##_name =      \
>> +			__ATTR(_name, 0444, ddw_##_name##_show, NULL)
>> +#define DEVICE_ATTR_DMA(_name)                              \
>> +		struct device_attribute dev_attr_dma_##_name =      \
>> +		__ATTR(_name, 0444, dma_##_name##_show, NULL)
>> +
>> +static DEVICE_ATTR_DDW(direct_address);
>> +static DEVICE_ATTR_DDW(direct_size);
>> +static DEVICE_ATTR_DDW(page_size);
>> +static DEVICE_ATTR_DDW(window_type);
>> +static DEVICE_ATTR_DDW(dynamic_address);
>> +static DEVICE_ATTR_DDW(dynamic_size);
>> +static DEVICE_ATTR_DDW(dynamic_pages_mapped);
>> +static DEVICE_ATTR_DMA(dynamic_address);
>> +static DEVICE_ATTR_DMA(dynamic_size);
>> +static DEVICE_ATTR_DMA(page_size);
>> +static DEVICE_ATTR_DMA(dynamic_pages_mapped);
>> +
>> +static struct attribute *spapr_tce_ddw_attrs[] = {
>> +	&dev_attr_ddw_direct_address.attr,
>> +	&dev_attr_ddw_direct_size.attr,
>> +	&dev_attr_ddw_page_size.attr,
>> +	&dev_attr_ddw_window_type.attr,
>> +	&dev_attr_ddw_dynamic_address.attr,
>> +	&dev_attr_ddw_dynamic_size.attr,
>> +	&dev_attr_ddw_dynamic_pages_mapped.attr,
>> +	NULL,
>> +};
>> +
>> +static struct attribute *spapr_tce_dma_attrs[] = {
>> +	&dev_attr_dma_dynamic_address.attr,
>> +	&dev_attr_dma_dynamic_size.attr,
>> +	&dev_attr_dma_page_size.attr,
>> +	&dev_attr_dma_dynamic_pages_mapped.attr,
>> +	NULL,
>> +};
>> +
>> +static struct attribute_group spapr_tce_ddw_group = {
>> +	.name = "spapr-tce-ddw",
>> +	.attrs = spapr_tce_ddw_attrs,
>> +};
>> +
>> +static struct attribute_group spapr_tce_dma_group = {
>> +	.name = "spapr-tce-dma",
>> +	.attrs = spapr_tce_dma_attrs,
>> +};
>> +
> These attributes are PSeries specific but they are being setup in ppc
> generic iommu code at arch/powerpc/kernel/iommu.c . Can you move these
> attributes to arch/powerpc/platforms/pseries/iommu.c
>
>>   static struct attribute *spapr_tce_iommu_attrs[] = {
>>   	NULL,
>>   };
>> @@ -1280,6 +1513,8 @@ static struct attribute_group spapr_tce_iommu_group = {
>>   
>>   static const struct attribute_group *spapr_tce_iommu_groups[] = {
>>   	&spapr_tce_iommu_group,
>> +	&spapr_tce_ddw_group,
>> +	&spapr_tce_dma_group,
>>   	NULL,
>>   };
>>   
>> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
>> index 5497b130e026..5d04b50ae265 100644
>> --- a/arch/powerpc/platforms/pseries/iommu.c
>> +++ b/arch/powerpc/platforms/pseries/iommu.c
>> @@ -837,6 +837,162 @@ static struct device_node *pci_dma_find(struct device_node *dn,
>>   	return rdn;
>>   }
>>   
>> +static unsigned long iommu_table_inuse_tces(struct iommu_table *tbl)
>> +{
>> +	struct iommu_pool *pool;
>> +	unsigned long ntces = 0;
>> +
>> +	/* Number of TCEs in-use */
>> +	for (int i = 0; i < tbl->nr_pools; i++) {
>> +		pool = &tbl->pools[i];
>> +		ntces += pool->inuse;
>> +	}
>> +
>> +	pool = &tbl->large_pool;
>> +	ntces += pool->inuse;
>> +
>> +	return ntces;
>> +}
> It would be better to use this functions as a callback in
> iommu_table_ops which can be implemented by pseries and powernv code
> differently.
>
>
>> +
>> +/* Get DDW information for the device */
>> +int gather_ddw_info(struct device *dev, struct dma_win_data *data)
>> +{
>> +	struct iommu_device *iommu;
>> +	struct pci_controller *phb;
>> +	struct device_node *dn;
>> +	struct pci_dn *pci;
>> +	const __be32 *prop = NULL;
>> +	bool ddw_direct = false;
>> +	bool found = false;
>> +	struct iommu_table *tbl;
>> +	u32 pgshift;
>> +	struct dynamic_dma_window_prop *p;
>> +
>> +	memset(data, 0, sizeof(*data));
>> +
>> +	iommu = dev_get_drvdata(dev);
>> +	phb = container_of(iommu, struct pci_controller, iommu);
>> +	dn = phb->dn;
>> +
>> +	if (!dn)
>> +		return SPAPR_ERROR;
>> +
>> +	pci = PCI_DN(dn);
>> +	if (!pci || !pci->table_group)
>> +		return SPAPR_ERROR;
>> +
>> +	/* Find DDW */
>> +	prop = of_get_property(dn, DIRECT64_PROPNAME, NULL);
>> +	if (prop) {
>> +		ddw_direct = true;
>> +		found = true;
>> +	} else {
>> +		prop = of_get_property(dn, DMA64_PROPNAME, NULL);
>> +		if (prop)
>> +			found = true;
>> +	}
>> +
>> +	/* NO DDW */
>> +	if (!found)
>> +		return SPAPR_NODDWWIN;
>> +
>> +	p = (struct dynamic_dma_window_prop *)prop;
>> +
>> +	pgshift = be32_to_cpu(p->tce_shift);
>> +	if (pgshift != 0xc && pgshift != 0x10 && pgshift != 0x15)
>> +		data->win_pgsize = 0;
>> +	else
>> +		data->win_pgsize = 1 << pgshift;
>> +
>> +	/* Check if DDW has table associated with it. Having a table associated with
>> +	 * DDW is indicative that is has some dynamic TCE allocations. In this case the
>> +	 * DDW can be fully Dynamic or in Hybrid mode. For SR-IOV DDW is on index 0,
>> +	 * for dedicated adapter on index 1.
>> +	 */
>> +	found = false;
>> +	for (int i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
>> +		tbl = pci->table_group->tables[i];
>> +
>> +		if (tbl && tbl->it_index == be32_to_cpu(p->liobn)) {
>> +			found = true;
>> +			break;
>> +		}
>> +	}
>> +
>> +	/* set the parameters depnding on the DDW type */
>> +	if (ddw_direct && found) {          /* Hybrid */
>> +		data->direct_addr = be64_to_cpu(p->dma_base);
>> +		data->dynamic_size = (u64)(tbl->it_size << tbl->it_page_shift);
>> +
>> +		data->dynamic_addr = data->direct_addr
>> +								+ (u64)(1UL << be32_to_cpu(p->window_shift))
>> +								- data->dynamic_size;
>> +
>> +		data->direct_size = data->dynamic_addr - data->direct_addr;
>> +		data->dynamic_tces_inuse = iommu_table_inuse_tces(tbl);
>> +
>> +		sprintf(data->win_type, "%s", "Hybrid");
>> +	} else if (ddw_direct && !found) {    /* Direct */
>> +		data->direct_addr = be64_to_cpu(p->dma_base);
>> +		data->direct_size = (u64)(1UL << be32_to_cpu(p->window_shift));
>> +
>> +		sprintf(data->win_type, "%s", "Direct");
>> +	} else {                              /* Dynamic */
>> +		data->dynamic_addr = be64_to_cpu(p->dma_base);
>> +		data->dynamic_size = (u64)(1UL << be32_to_cpu(p->window_shift));
>> +		data->dynamic_tces_inuse = iommu_table_inuse_tces(tbl);
>> +
>> +		sprintf(data->win_type, "%s", "Dynamic");
>> +	}
>> +
>> +	return SPAPR_SUCCESS;
>> +}
>> +
>> +/* Get DDW information for the device */
>> +int gather_dma_info(struct device *dev, struct dma_win_data *data)
>> +{
>> +	struct iommu_device *iommu;
>> +	struct pci_controller *phb;
>> +	struct device_node *dn;
>> +	struct pci_dn *pci;
>> +	const __be32 *prop = NULL;
>> +	struct iommu_table *tbl;
>> +	unsigned long offset, size, liobn;
>> +
>> +	memset(data, 0, sizeof(*data));
>> +
>> +	iommu = dev_get_drvdata(dev);
>> +	phb = container_of(iommu, struct pci_controller, iommu);
>> +	dn = phb->dn;
>> +
>> +	if (!dn)
>> +		return SPAPR_ERROR;
>> +
>> +	pci = PCI_DN(dn);
>> +	if (!pci || !pci->table_group)
>> +		return SPAPR_ERROR;
>> +
>> +	/* search for default DMA window */
>> +	prop = of_get_property(dn, "ibm,dma-window", NULL);
>> +
>> +	if (!prop)
>> +		return SPAPR_NODMAWIN;
>> +
>> +	/* default DMA Window is always at index 0 */
>> +	tbl = pci->table_group->tables[0];
>> +	if (!tbl)
>> +		return SPAPR_ERROR;
>> +
>> +	of_parse_dma_window(dn, prop, &liobn, &offset, &size);
>> +
>> +	data->dynamic_addr = offset;
>> +	data->dynamic_size = size;
>> +	data->win_pgsize = 1ULL << IOMMU_PAGE_SHIFT_4K;
>> +	data->dynamic_tces_inuse = iommu_table_inuse_tces(tbl);
>> +
>> +	return SPAPR_SUCCESS;
>> +}
>> +
>>   static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
>>   {
>>   	struct iommu_table *tbl;
>>
>> base-commit: 192c0159402e6bfbe13de6f8379546943297783d
>> -- 
>> 2.39.3
>>