On 29/08/2020 00:04, Leonardo Bras wrote: > On Mon, 2020-08-24 at 13:44 +1000, Alexey Kardashevskiy wrote: >> >>> On 18/08/2020 09:40, Leonardo Bras wrote: >>> 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 <leobra...@gmail.com> >>> --- >>> arch/powerpc/platforms/pseries/iommu.c | 30 ++++++++++++-------------- >>> 1 file changed, 14 insertions(+), 16 deletions(-) >>> >>> diff --git a/arch/powerpc/platforms/pseries/iommu.c >>> b/arch/powerpc/platforms/pseries/iommu.c >>> index fcdefcc0f365..4031127c9537 100644 >>> --- a/arch/powerpc/platforms/pseries/iommu.c >>> +++ b/arch/powerpc/platforms/pseries/iommu.c >>> @@ -852,24 +852,25 @@ static void remove_ddw(struct device_node *np, bool >>> remove_prop) >>> np, ret); >>> } >>>> >>> -static u64 find_existing_ddw(struct device_node *pdn) >>> +static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr) >>> { >>> 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); >>> + found = true; >>> break; >>> } >>> } >>> spin_unlock(&direct_window_list_lock); >>> >>> - return dma_addr; >>> + return found; >>> } >>> >>> static struct direct_window *ddw_list_add(struct device_node *pdn, >>> @@ -1131,15 +1132,15 @@ static void reset_dma_window(struct pci_dev *dev, >>> struct device_node *par_dn) >>> * 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, ret; >>> struct ddw_query_response query; >>> struct ddw_create_response create; >>> int page_shift; >>> - u64 dma_addr, max_addr; >>> + u64 max_addr; >>> struct device_node *dn; >>> u32 ddw_avail[DDW_APPLICABLE_SIZE]; >>> struct direct_window *window; >>> @@ -1150,8 +1151,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct >>> device_node *pdn) >>> >>> mutex_lock(&direct_window_init_mutex); >>> >>> - dma_addr = find_existing_ddw(pdn); >>> - if (dma_addr != 0) >>> + if (find_existing_ddw(pdn, &dev->dev.archdata.dma_offset)) >>> goto out_unlock; >>> >>> /* >>> @@ -1292,7 +1292,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct >>> device_node *pdn) >>> goto out_free_window; >>> } >>> >>> - dma_addr = be64_to_cpu(ddwprop->dma_base); >>> + dev->dev.archdata.dma_offset = be64_to_cpu(ddwprop->dma_base); >> >> Do not you need the same chunk in the find_existing_ddw() case above as >> well? Thanks, > > The new signature of find_existing_ddw() is > static bool find_existing_ddw(struct device_node *pdn, u64 *dma_addr) > > And on enable_ddw(), we call > find_existing_ddw(pdn, &dev->dev.archdata.dma_offset) > > And inside the function we do: > *dma_addr = be64_to_cpu(direct64->dma_base); > > I think it's the same as the chunk before. > Am I missing something? ah no, sorry, you are not missing anything. Reviewed-by: Alexey Kardashevskiy <a...@ozlabs.ru> -- Alexey