[v2,14/14] powerpc/pseries/iommu: Rename "direct window" to "dma window"

Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, 

A previous change introduced the usage of DDW as a bigger indirect DMA
mapping when the DDW available size does not map the whole partition.

As most of the code that manipulates direct mappings was reused for
indirect mappings, it's necessary to rename all names and debug/info
messages to reflect that it can be used for both kinds of mapping.

Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
it's the name of the default DMA window.

Those changes are not supposed to change how the code works in any
way, just adjust naming.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
 arch/powerpc/platforms/pseries/iommu.c | 102 +++++++++++++------------
 1 file changed, 53 insertions(+), 49 deletions(-)

On 12/09/2020 03:07, Leonardo Bras wrote:
> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
> 
> A previous change introduced the usage of DDW as a bigger indirect DMA
> mapping when the DDW available size does not map the whole partition.
> 
> As most of the code that manipulates direct mappings was reused for
> indirect mappings, it's necessary to rename all names and debug/info
> messages to reflect that it can be used for both kinds of mapping.
> 
> Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
> it's the name of the default DMA window.

"ibm,dma-window" is so old so it does not need a macro (which btw would 
be DMA_WIN_PROPNAME to match the other names) :)


> Those changes are not supposed to change how the code works in any
> way, just adjust naming.

I simply have this in my .vimrc for the cases like this one:

===
This should cause no behavioural change.
===


> 
> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 102 +++++++++++++------------
>   1 file changed, 53 insertions(+), 49 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index c4de23080d1b..56638b7f07fc 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -349,7 +349,7 @@ struct dynamic_dma_window_prop {
>   	__be32	window_shift;	/* ilog2(tce_window_size) */
>   };
>   
> -struct direct_window {
> +struct dma_win {
>   	struct device_node *device;
>   	const struct dynamic_dma_window_prop *prop;
>   	struct list_head list;
> @@ -369,13 +369,14 @@ struct ddw_create_response {
>   	u32 addr_lo;
>   };
>   
> -static LIST_HEAD(direct_window_list);
> +static LIST_HEAD(dma_win_list);
>   /* prevents races between memory on/offline and window creation */
> -static DEFINE_SPINLOCK(direct_window_list_lock);
> +static DEFINE_SPINLOCK(dma_win_list_lock);
>   /* protects initializing window twice for same device */
> -static DEFINE_MUTEX(direct_window_init_mutex);
> +static DEFINE_MUTEX(dma_win_init_mutex);
>   #define DIRECT64_PROPNAME "linux,direct64-ddr-window-info"
>   #define DMA64_PROPNAME "linux,dma64-ddr-window-info"
> +#define DEFAULT_DMA_WIN "ibm,dma-window"
>   
>   static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
>   					unsigned long num_pfn, const void *arg)
> @@ -706,15 +707,18 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
>   	pr_debug("pci_dma_bus_setup_pSeriesLP: setting up bus %pOF\n",
>   		 dn);
>   
> -	/* Find nearest ibm,dma-window, walking up the device tree */
> +	/*
> +	 * Find nearest ibm,dma-window (default DMA window), walking up the
> +	 * device tree
> +	 */
>   	for (pdn = dn; pdn != NULL; pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window != NULL)
>   			break;
>   	}
>   
>   	if (dma_window == NULL) {
> -		pr_debug("  no ibm,dma-window property !\n");
> +		pr_debug("  no %s property !\n", DEFAULT_DMA_WIN);
>   		return;
>   	}
>   
> @@ -810,11 +814,11 @@ static void remove_dma_window(struct device_node *np, u32 *ddw_avail,
>   
>   	ret = rtas_call(ddw_avail[DDW_REMOVE_PE_DMA_WIN], 1, 1, NULL, liobn);
>   	if (ret)
> -		pr_warn("%pOF: failed to remove direct window: rtas returned "
> +		pr_warn("%pOF: failed to remove dma window: rtas returned "
>   			"%d to ibm,remove-pe-dma-window(%x) %llx\n",
>   			np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
>   	else
> -		pr_debug("%pOF: successfully removed direct window: rtas returned "
> +		pr_debug("%pOF: successfully removed dma window: rtas returned "


s/dma/DMA/ in all user visible strings.



>   			"%d to ibm,remove-pe-dma-window(%x) %llx\n",
>   			np, ret, ddw_avail[DDW_REMOVE_PE_DMA_WIN], liobn);
>   }
> @@ -842,7 +846,7 @@ static int remove_ddw(struct device_node *np, bool remove_prop, const char *win_
>   
>   	ret = of_remove_property(np, win);
>   	if (ret)
> -		pr_warn("%pOF: failed to remove direct window property: %d\n",
> +		pr_warn("%pOF: failed to remove dma window property: %d\n",
>   			np, ret);
>   	return 0;
>   }
> @@ -886,34 +890,34 @@ static phys_addr_t ddw_memory_hotplug_max(void)
>   
>   static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, bool *direct_mapping)
>   {
> -	struct direct_window *window;
> -	const struct dynamic_dma_window_prop *direct64;
> +	struct dma_win *window;
> +	const struct dynamic_dma_window_prop *dma64;
>   	unsigned long window_size;
>   	bool found = false;
>   
> -	spin_lock(&direct_window_list_lock);
> +	spin_lock(&dma_win_list_lock);
>   	/* check if we already created a window and dupe that config if so */
> -	list_for_each_entry(window, &direct_window_list, list) {
> +	list_for_each_entry(window, &dma_win_list, list) {
>   		if (window->device == pdn) {
> -			direct64 = window->prop;
> -			*dma_addr = be64_to_cpu(direct64->dma_base);
> +			dma64 = window->prop;
> +			*dma_addr = be64_to_cpu(dma64->dma_base);
>   
> -			window_size = (1UL << be32_to_cpu(direct64->window_shift));
> +			window_size = (1UL << be32_to_cpu(dma64->window_shift));
>   			*direct_mapping = (window_size >= ddw_memory_hotplug_max());
>   
>   			found = true;
>   			break;
>   		}
>   	}
> -	spin_unlock(&direct_window_list_lock);
> +	spin_unlock(&dma_win_list_lock);
>   
>   	return found;
>   }
>   
> -static struct direct_window *ddw_list_new_entry(struct device_node *pdn,
> -						const struct dynamic_dma_window_prop *dma64)
> +static struct dma_win *ddw_list_new_entry(struct device_node *pdn,
> +					  const struct dynamic_dma_window_prop *dma64)
>   {
> -	struct direct_window *window;
> +	struct dma_win *window;
>   
>   	window = kzalloc(sizeof(*window), GFP_KERNEL);
>   	if (!window)
> @@ -929,7 +933,7 @@ static void find_existing_ddw_windows_named(const char *name)
>   {
>   	int len;
>   	struct device_node *pdn;
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	const struct dynamic_dma_window_prop *dma64;
>   
>   	for_each_node_with_property(pdn, name) {
> @@ -943,9 +947,9 @@ static void find_existing_ddw_windows_named(const char *name)
>   		if (!window)
>   			break;
>   
> -		spin_lock(&direct_window_list_lock);
> -		list_add(&window->list, &direct_window_list);
> -		spin_unlock(&direct_window_list_lock);
> +		spin_lock(&dma_win_list_lock);
> +		list_add(&window->list, &dma_win_list);
> +		spin_unlock(&dma_win_list_lock);
>   	}
>   }
>   
> @@ -1179,7 +1183,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	u64 max_addr, win_addr;
>   	struct device_node *dn;
>   	u32 ddw_avail[DDW_APPLICABLE_SIZE];
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	const char *win_name;
>   	struct property *win64 = NULL;
>   	struct failed_ddw_pdn *fpdn;
> @@ -1187,10 +1191,10 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	struct pci_dn *pci = PCI_DN(pdn);
>   	struct iommu_table *tbl = pci->table_group->tables[0];
>   
> -	mutex_lock(&direct_window_init_mutex);
> +	mutex_lock(&dma_win_init_mutex);
>   
>   	if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &direct_mapping)) {
> -		mutex_unlock(&direct_window_init_mutex);
> +		mutex_unlock(&dma_win_init_mutex);
>   		return direct_mapping;
>   	}
>   
> @@ -1241,7 +1245,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		struct property *default_win;
>   		int reset_win_ext;
>   
> -		default_win = of_find_property(pdn, "ibm,dma-window", NULL);
> +		default_win = of_find_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (!default_win)
>   			goto out_failed;
>   
> @@ -1272,8 +1276,8 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	} else if ((query.page_size & 1) && PAGE_SHIFT >= 12) {
>   		page_shift = 12; /* 4kB */
>   	} else {
> -		dev_dbg(&dev->dev, "no supported direct page size in mask %x",
> -			  query.page_size);
> +		dev_dbg(&dev->dev, "no supported page size in mask %x",
> +			query.page_size);
>   		goto out_failed;
>   	}
>   
> @@ -1331,7 +1335,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
>   					    win64->value, tce_setrange_multi_pSeriesLP_walk);
>   		if (ret) {
> -			dev_info(&dev->dev, "failed to map direct window for %pOF: %d\n",
> +			dev_info(&dev->dev, "failed to map DMA window for %pOF: %d\n",
>   				 dn, ret);
>   			goto out_list_del;
>   		}
> @@ -1354,9 +1358,9 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   		set_iommu_table_base(&dev->dev, tbl);
>   	}
>   
> -	spin_lock(&direct_window_list_lock);
> -	list_add(&window->list, &direct_window_list);
> -	spin_unlock(&direct_window_list_lock);
> +	spin_lock(&dma_win_list_lock);
> +	list_add(&window->list, &dma_win_list);
> +	spin_unlock(&dma_win_list_lock);
>   
>   	dev->dev.archdata.dma_offset = win_addr;
>   	goto out_unlock;
> @@ -1387,7 +1391,7 @@ static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>   	list_add(&fpdn->list, &failed_ddw_pdn_list);
>   
>   out_unlock:
> -	mutex_unlock(&direct_window_init_mutex);
> +	mutex_unlock(&dma_win_init_mutex);
>   	return win64 && direct_mapping;
>   }
>   
> @@ -1411,7 +1415,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
>   
>   	for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
>   	     pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window)
>   			break;
>   	}
> @@ -1461,7 +1465,7 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
>   	 */
>   	for (pdn = dn; pdn && PCI_DN(pdn) && !PCI_DN(pdn)->table_group;
>   			pdn = pdn->parent) {
> -		dma_window = of_get_property(pdn, "ibm,dma-window", NULL);
> +		dma_window = of_get_property(pdn, DEFAULT_DMA_WIN, NULL);
>   		if (dma_window)
>   			break;
>   	}
> @@ -1475,29 +1479,29 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
>   static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
>   		void *data)
>   {
> -	struct direct_window *window;
> +	struct dma_win *window;
>   	struct memory_notify *arg = data;
>   	int ret = 0;
>   
>   	switch (action) {
>   	case MEM_GOING_ONLINE:
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			ret |= tce_setrange_multi_pSeriesLP(arg->start_pfn,
>   					arg->nr_pages, window->prop);
>   			/* XXX log error */
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	case MEM_CANCEL_ONLINE:
>   	case MEM_OFFLINE:
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			ret |= tce_clearrange_multi_pSeriesLP(arg->start_pfn,
>   					arg->nr_pages, window->prop);
>   			/* XXX log error */
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	default:
>   		break;
> @@ -1518,7 +1522,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
>   	struct of_reconfig_data *rd = data;
>   	struct device_node *np = rd->dn;
>   	struct pci_dn *pci = PCI_DN(np);
> -	struct direct_window *window;
> +	struct dma_win *window;
>   
>   	switch (action) {
>   	case OF_RECONFIG_DETACH_NODE:
> @@ -1537,15 +1541,15 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
>   			iommu_pseries_free_group(pci->table_group,
>   					np->full_name);
>   
> -		spin_lock(&direct_window_list_lock);
> -		list_for_each_entry(window, &direct_window_list, list) {
> +		spin_lock(&dma_win_list_lock);
> +		list_for_each_entry(window, &dma_win_list, list) {
>   			if (window->device == np) {
>   				list_del(&window->list);
>   				kfree(window);
>   				break;
>   			}
>   		}
> -		spin_unlock(&direct_window_list_lock);
> +		spin_unlock(&dma_win_list_lock);
>   		break;
>   	default:
>   		err = NOTIFY_DONE;
>

On Tue, 2020-09-29 at 13:55 +1000, Alexey Kardashevskiy wrote:
> 
> On 12/09/2020 03:07, Leonardo Bras wrote:
> > Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
> > 
> > A previous change introduced the usage of DDW as a bigger indirect DMA
> > mapping when the DDW available size does not map the whole partition.
> > 
> > As most of the code that manipulates direct mappings was reused for
> > indirect mappings, it's necessary to rename all names and debug/info
> > messages to reflect that it can be used for both kinds of mapping.
> > 
> > Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
> > it's the name of the default DMA window.
> 
> "ibm,dma-window" is so old so it does not need a macro (which btw would 
> be DMA_WIN_PROPNAME to match the other names) :)

Thanks for bringing that to my attention!
In fact, DMA_WIN_PROPNAME makes more sense, but it's still generic and
doesn't look to point to a generic one.

Would that be ok to call it DEFAULT_WIN_PROPNAME ?


> 
> 
> > Those changes are not supposed to change how the code works in any
> > way, just adjust naming.
> 
> I simply have this in my .vimrc for the cases like this one:
> 
> ===
> This should cause no behavioural change.
> ===

Great tip! I will make sure to have this saved here :)

Thank you!

On 30/09/2020 06:54, Leonardo Bras wrote:
> On Tue, 2020-09-29 at 13:55 +1000, Alexey Kardashevskiy wrote:
>>
>> On 12/09/2020 03:07, Leonardo Bras wrote:
>>> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
>>>
>>> A previous change introduced the usage of DDW as a bigger indirect DMA
>>> mapping when the DDW available size does not map the whole partition.
>>>
>>> As most of the code that manipulates direct mappings was reused for
>>> indirect mappings, it's necessary to rename all names and debug/info
>>> messages to reflect that it can be used for both kinds of mapping.
>>>
>>> Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
>>> it's the name of the default DMA window.
>>
>> "ibm,dma-window" is so old so it does not need a macro (which btw would
>> be DMA_WIN_PROPNAME to match the other names) :)
> 
> Thanks for bringing that to my attention!
> In fact, DMA_WIN_PROPNAME makes more sense, but it's still generic and
> doesn't look to point to a generic one.
> 
> Would that be ok to call it DEFAULT_WIN_PROPNAME ?


I would not touch it at all, the property name is painfully known and 
not going to change ever. Does anyone else define it as a macro? I do 
not see any:

[fstn1-p1 kernel-dma-bypass]$ git grep "ibm,dma-window"  | wc -l
8
[fstn1-p1 kernel-dma-bypass]$ git grep "define.*ibm,dma-window"  | wc -l
0



> 
> 
>>
>>
>>> Those changes are not supposed to change how the code works in any
>>> way, just adjust naming.
>>
>> I simply have this in my .vimrc for the cases like this one:
>>
>> ===
>> This should cause no behavioural change.
>> ===
> 
> Great tip! I will make sure to have this saved here :)
> 
> Thank you!
>

On Wed, 2020-09-30 at 17:29 +1000, Alexey Kardashevskiy wrote:
> 
> On 30/09/2020 06:54, Leonardo Bras wrote:
> > On Tue, 2020-09-29 at 13:55 +1000, Alexey Kardashevskiy wrote:
> > > 
> > > On 12/09/2020 03:07, Leonardo Bras wrote:
> > > > Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
> > > > 
> > > > A previous change introduced the usage of DDW as a bigger indirect DMA
> > > > mapping when the DDW available size does not map the whole partition.
> > > > 
> > > > As most of the code that manipulates direct mappings was reused for
> > > > indirect mappings, it's necessary to rename all names and debug/info
> > > > messages to reflect that it can be used for both kinds of mapping.
> > > > 
> > > > Also, defines DEFAULT_DMA_WIN as "ibm,dma-window" to document that
> > > > it's the name of the default DMA window.
> > > 
> > > "ibm,dma-window" is so old so it does not need a macro (which btw would
> > > be DMA_WIN_PROPNAME to match the other names) :)
> > 
> > Thanks for bringing that to my attention!
> > In fact, DMA_WIN_PROPNAME makes more sense, but it's still generic and
> > doesn't look to point to a generic one.
> > 
> > Would that be ok to call it DEFAULT_WIN_PROPNAME ?
> 
> 
> I would not touch it at all, the property name is painfully known and 
> not going to change ever. Does anyone else define it as a macro? I do 
> not see any:

Ok then, reverting define :)

Thanks!

> 
> [fstn1-p1 kernel-dma-bypass]$ git grep "ibm,dma-window"  | wc -l
> 8
> [fstn1-p1 kernel-dma-bypass]$ git grep "define.*ibm,dma-window"  | wc -l
> 0
> 
> 
> 
> > 
> > 
> > > 
> > > 
> > > > Those changes are not supposed to change how the code works in any
> > > > way, just adjust naming.
> > > 
> > > I simply have this in my .vimrc for the cases like this one:
> > > 
> > > ===
> > > This should cause no behavioural change.
> > > ===
> > 
> > Great tip! I will make sure to have this saved here :)
> > 
> > Thank you!
> > 
>