Messages in this thread | | | Subject | Re: [PATCH 3/4] powerpc/pseries/iommu: Move window-removing part of remove_ddw into remove_dma_window | From | Alexey Kardashevskiy <> | Date | Tue, 23 Jun 2020 11:12:22 +1000 |
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On 23/06/2020 04:59, Leonardo Bras wrote: > Hello Alexey, thanks for the feedback! > > On Mon, 2020-06-22 at 20:02 +1000, Alexey Kardashevskiy wrote: >> >> On 19/06/2020 15:06, Leonardo Bras wrote: >>> Move the window-removing part of remove_ddw into a new function >>> (remove_dma_window), so it can be used to remove other DMA windows. >>> >>> It's useful for removing DMA windows that don't create DIRECT64_PROPNAME >>> property, like the default DMA window from the device, which uses >>> "ibm,dma-window". >>> >>> Signed-off-by: Leonardo Bras <leobras.c@gmail.com> >>> --- >>> arch/powerpc/platforms/pseries/iommu.c | 53 +++++++++++++++----------- >>> 1 file changed, 31 insertions(+), 22 deletions(-) >>> >>> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c >>> index 5e1fbc176a37..de633f6ae093 100644 >>> --- a/arch/powerpc/platforms/pseries/iommu.c >>> +++ b/arch/powerpc/platforms/pseries/iommu.c >>> @@ -767,25 +767,14 @@ static int __init disable_ddw_setup(char *str) >>> >>> early_param("disable_ddw", disable_ddw_setup); >>> >>> -static void remove_ddw(struct device_node *np, bool remove_prop) >>> +static void remove_dma_window(struct device_node *pdn, u32 *ddw_avail, >> >> You do not need the entire ddw_avail here, pass just the token you need. > > Well, I just emulated the behavior of create_ddw() and query_ddw() as > both just pass the array instead of the token, even though they only > use a single token.
True, there is a pattern.
> I think it's to make the rest of the code independent of the design of > the "ibm,ddw-applicable" array, and if it changes, only local changes > on the functions will be needed.
The helper removes a window, if you are going to call other operations in remove_dma_window(), then you'll have to change its name ;)
>> Also, despite this particular file, the "pdn" name is usually used for >> struct pci_dn (not device_node), let's keep it that way. > > Sure, I got confused for some time about this, as we have: > static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn). > but on *_ddw() we have "struct pci_dn *pdn".
True again, not the cleanest style here.
> I will also add a patch that renames those 'struct device_node *pdn' to > something like 'struct device_node *parent_dn'.
I would not go that far, we (well, Oliver) are getting rid of many occurrences of pci_dn and Oliver may have a stronger opinion here.
> >>> + struct property *win) >>> { >>> struct dynamic_dma_window_prop *dwp; >>> - struct property *win64; >>> - u32 ddw_avail[3]; >>> u64 liobn; >>> - int ret = 0; >>> - >>> - ret = of_property_read_u32_array(np, "ibm,ddw-applicable", >>> - &ddw_avail[0], 3); >>> - >>> - win64 = of_find_property(np, DIRECT64_PROPNAME, NULL); >>> - if (!win64) >>> - return; >>> - >>> - if (ret || win64->length < sizeof(*dwp)) >>> - goto delprop; >>> + int ret; >>> >>> - dwp = win64->value; >>> + dwp = win->value; >>> liobn = (u64)be32_to_cpu(dwp->liobn); >>> >>> /* clear the whole window, note the arg is in kernel pages */ >>> @@ -793,24 +782,44 @@ static void remove_ddw(struct device_node *np, bool remove_prop) >>> 1ULL << (be32_to_cpu(dwp->window_shift) - PAGE_SHIFT), dwp); >>> if (ret) >>> pr_warn("%pOF failed to clear tces in window.\n", >>> - np); >>> + pdn); >>> else >>> pr_debug("%pOF successfully cleared tces in window.\n", >>> - np); >>> + pdn); >>> >>> ret = rtas_call(ddw_avail[2], 1, 1, NULL, liobn); >>> if (ret) >>> pr_warn("%pOF: failed to remove direct window: rtas returned " >>> "%d to ibm,remove-pe-dma-window(%x) %llx\n", >>> - np, ret, ddw_avail[2], liobn); >>> + pdn, ret, ddw_avail[2], liobn); >>> else >>> pr_debug("%pOF: successfully removed direct window: rtas returned " >>> "%d to ibm,remove-pe-dma-window(%x) %llx\n", >>> - np, ret, ddw_avail[2], liobn); >>> + pdn, ret, ddw_avail[2], liobn); >>> +} >>> + >>> +static void remove_ddw(struct device_node *np, bool remove_prop) >>> +{ >>> + struct property *win; >>> + u32 ddw_avail[3]; >>> + int ret = 0; >>> + >>> + ret = of_property_read_u32_array(np, "ibm,ddw-applicable", >>> + &ddw_avail[0], 3); >>> + if (ret) >>> + return; >>> + >>> + win = of_find_property(np, DIRECT64_PROPNAME, NULL); >>> + if (!win) >>> + return; >>> + >>> + if (win->length >= sizeof(struct dynamic_dma_window_prop)) >> >> Any good reason not to make it "=="? Is there something optional or we >> expect extension (which may not grow from the end but may add cells in >> between). Thanks, > > Well, it comes from the old behavior of remove_ddw(): > - if (ret || win64->length < sizeof(*dwp)) > - goto delprop; > As I reversed the logic from 'if (test) go out' to 'if (!test) do > stuff', I also reversed (a < b) to !(a < b) => (a >= b). > > I have no problem changing that to '==', but it will produce a > different behavior than before.
I missed than, never mind then.
> >> >> >>> + remove_dma_window(np, ddw_avail, win); >>> + >>> + if (!remove_prop) >>> + return; >>> >>> -delprop: >>> - if (remove_prop) >>> - ret = of_remove_property(np, win64); >>> + ret = of_remove_property(np, win); >>> if (ret) >>> pr_warn("%pOF: failed to remove direct window property: %d\n", >>> np, ret); >>> > > Best regards, > Leonardo >
-- Alexey
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