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powerpc/pseries/iommu: Allow DDW windows starting at 0x00 

enable_ddw() currently returns the address of the DMA window, which is
considered invalid if has the value 0x00.

Also, it only considers valid an address returned from find_existing_ddw
if it's not 0x00.

Changing this behavior makes sense, given the users of enable_ddw() only
need to know if direct mapping is possible. It can also allow a DMA window
starting at 0x00 to be used.

This will be helpful for using a DDW with indirect mapping, as the window
address will be different than 0x00, but it will not map the whole
partition.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210817063929.38701-6-leobras.c@gmail.com
This commit is contained in:
Leonardo Bras 2021-08-17 03:39:23 -03:00 committed by Michael Ellerman
parent 92a2321929
commit 2ca73c54ce
1 changed files with 18 additions and 18 deletions
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36
arch/powerpc/platforms/pseries/iommu.c
View File

@ -853,25 +853,26 @@ static void remove_ddw(struct device_node *np, bool remove_prop)
np, ret);
}
static u64 find_existing_ddw(struct device_node *pdn, int *window_shift)
static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr, int *window_shift)
{
struct direct_window *window;
const struct dynamic_dma_window_prop *direct64;
u64 dma_addr = 0;
bool found = false;
spin_lock(&direct_window_list_lock);
/* check if we already created a window and dupe that config if so */
list_for_each_entry(window, &direct_window_list, list) {
if (window->device == pdn) {
direct64 = window->prop;
dma_addr = be64_to_cpu(direct64->dma_base);
*dma_addr = be64_to_cpu(direct64->dma_base);
*window_shift = be32_to_cpu(direct64->window_shift);
found = true;
break;
}
}
spin_unlock(&direct_window_list_lock);
return dma_addr;
return found;
}
static struct direct_window *ddw_list_new_entry(struct device_node *pdn,
@ -1161,20 +1162,20 @@ static int iommu_get_page_shift(u32 query_page_size)
* pdn: the parent pe node with the ibm,dma_window property
* Future: also check if we can remap the base window for our base page size
*
* returns the dma offset for use by the direct mapped DMA code.
* returns true if can map all pages (direct mapping), false otherwise..
*/
static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
static bool enable_ddw(struct pci_dev *dev, struct device_node *pdn)
{
int len = 0, ret;
int max_ram_len = order_base_2(ddw_memory_hotplug_max());
struct ddw_query_response query;
struct ddw_create_response create;
int page_shift;
u64 dma_addr;
struct device_node *dn;
u32 ddw_avail[DDW_APPLICABLE_SIZE];
struct direct_window *window;
struct property *win64;
bool ddw_enabled = false;
struct dynamic_dma_window_prop *ddwprop;
struct failed_ddw_pdn *fpdn;
bool default_win_removed = false;
@ -1186,9 +1187,10 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
mutex_lock(&direct_window_init_mutex);
dma_addr = find_existing_ddw(pdn, &len);
if (dma_addr != 0)
if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset, &len)) {
ddw_enabled = true;
goto out_unlock;
}
/*
* If we already went through this for a previous function of
@ -1342,7 +1344,8 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
list_add(&window->list, &direct_window_list);
spin_unlock(&direct_window_list_lock);
dma_addr = be64_to_cpu(ddwprop->dma_base);
dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base);
ddw_enabled = true;
goto out_unlock;
out_free_window:
@ -1374,10 +1377,10 @@ out_unlock:
* as RAM, then we failed to create a window to cover persistent
* memory and need to set the DMA limit.
*/
if (pmem_present && dma_addr && (len == max_ram_len))
dev->dev.bus_dma_limit = dma_addr + (1ULL << len);
if (pmem_present && ddw_enabled && (len == max_ram_len))
dev->dev.bus_dma_limit = dev->dev.archdata.dma_offset + (1ULL << len);
return dma_addr;
return ddw_enabled;
}
static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
@ -1456,11 +1459,8 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
break;
}
if (pdn && PCI_DN(pdn)) {
pdev->dev.archdata.dma_offset = enable_ddw(pdev, pdn);
if (pdev->dev.archdata.dma_offset)
return true;
}
if (pdn && PCI_DN(pdn))
return enable_ddw(pdev, pdn);
return false;
}