From: Leonardo Bras <leobras.c@gmail.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
Ram Pai <linuxram@us.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/6] powerpc/pseries/iommu: Update call to ibm,query-pe-dma-windows
Date: Wed, 01 Jul 2020 21:28:40 -0300 [thread overview]
Message-ID: <8f4c405363e4cd2a5a113f2a9a3f11a575d2947a.camel@gmail.com> (raw)
In-Reply-To: <47ad4907-5f63-56e1-2985-a7a7f4d0ba35@ozlabs.ru>
On Thu, 2020-07-02 at 10:18 +1000, Alexey Kardashevskiy wrote:
>
> On 02/07/2020 00:04, Leonardo Bras wrote:
> > On Wed, 2020-07-01 at 18:17 +1000, Alexey Kardashevskiy wrote:
> > > > +#define DDW_EXT_SIZE 0
> > > > +#define DDW_EXT_RESET_DMA_WIN 1
> > > > +#define DDW_EXT_QUERY_OUT_SIZE 2
> > >
> > > #define DDW_EXT_LAST (DDW_EXT_QUERY_OUT_SIZE + 1)
> > > ...
> > >
> > >
> > > > +
> > > > static struct iommu_table_group *iommu_pseries_alloc_group(int node)
> > > > {
> > > > struct iommu_table_group *table_group;
> > > > @@ -339,7 +343,7 @@ struct direct_window {
> > > > /* Dynamic DMA Window support */
> > > > struct ddw_query_response {
> > > > u32 windows_available;
> > > > - u32 largest_available_block;
> > > > + u64 largest_available_block;
> > > > u32 page_size;
> > > > u32 migration_capable;
> > > > };
> > > > @@ -875,13 +879,29 @@ static int find_existing_ddw_windows(void)
> > > > machine_arch_initcall(pseries, find_existing_ddw_windows);
> > > >
> > > > static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
> > > > - struct ddw_query_response *query)
> > > > + struct ddw_query_response *query,
> > > > + struct device_node *parent)
> > > > {
> > > > struct device_node *dn;
> > > > struct pci_dn *pdn;
> > > > - u32 cfg_addr;
> > > > + u32 cfg_addr, query_out[5], ddw_ext[DDW_EXT_QUERY_OUT_SIZE + 1];
> > >
> > > ... and use DDW_EXT_LAST here.
> >
> > Because of the growing nature of ddw-extensions, I intentionally let
> > this be (DDW_EXT_QUERY_OUT_SIZE + 1). If we create a DDW_EXT_LAST, it
> > will be incremented in the future if more extensions come to exist.
> >
> > I mean, I previously saw no reason for allocating space for extensions
> > after the desired one, as they won't be used here.
>
> Ah, my bad, you're right.
>
>
> > >
> > > > u64 buid;
> > > > - int ret;
> > > > + int ret, out_sz;
> > > > +
> > > > + /*
> > > > + * From LoPAR level 2.8, "ibm,ddw-extensions" index 3 can rule how many
> > > > + * output parameters ibm,query-pe-dma-windows will have, ranging from
> > > > + * 5 to 6.
> > > > + */
> > > > +
> > > > + ret = of_property_read_u32_array(parent, "ibm,ddw-extensions",
> > > > + &ddw_ext[0],
> > > > + DDW_EXT_QUERY_OUT_SIZE + 1);
> >
> > In this case, I made sure not to cross (DDW_EXT_QUERY_OUT_SIZE + 1)
> > while reading the extensions from the property.
> >
> > What do you think about it?
>
> I think you want something like:
>
> static inline int ddw_read_ext(const struct device_node *np, int extnum,
> u32 *ret)
> {
> retun of_property_read_u32_index(np, "ibm,ddw-extensions", extnum + 1, ret);
> }
>
> These "+1"'s all over the place are confusing.
That's a great idea!
I was not aware it was possible to read a single value[index] directly
from the property, but it makes total sense to use it.
Thank you!
next prev parent reply other threads:[~2020-07-02 0:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 6:24 [PATCH v2 0/6] Remove default DMA window before creating DDW Leonardo Bras
2020-06-24 6:24 ` [PATCH v2 1/6] powerpc/pseries/iommu: Create defines for operations in ibm,ddw-applicable Leonardo Bras
2020-07-01 8:16 ` Alexey Kardashevskiy
2020-07-01 13:28 ` Leonardo Bras
2020-07-02 0:21 ` Alexey Kardashevskiy
2020-07-02 0:36 ` Leonardo Bras
2020-07-02 0:43 ` Alexey Kardashevskiy
2020-07-02 0:46 ` Leonardo Bras
2020-06-24 6:24 ` [PATCH v2 2/6] powerpc/pseries/iommu: Update call to ibm,query-pe-dma-windows Leonardo Bras
2020-07-01 8:17 ` Alexey Kardashevskiy
2020-07-01 14:04 ` Leonardo Bras
2020-07-02 0:18 ` Alexey Kardashevskiy
2020-07-02 0:28 ` Leonardo Bras [this message]
2020-06-24 6:24 ` [PATCH v2 3/6] powerpc/pseries/iommu: Move window-removing part of remove_ddw into remove_dma_window Leonardo Bras
2020-06-24 6:24 ` [PATCH v2 4/6] powerpc/pseries/iommu: Remove default DMA window before creating DDW Leonardo Bras
2020-07-01 8:17 ` Alexey Kardashevskiy
2020-07-01 19:48 ` Leonardo Bras
2020-07-02 0:25 ` Alexey Kardashevskiy
2020-06-24 6:24 ` [PATCH v2 5/6] powerpc/pseries/iommu: Make use of DDW even if it does not map the partition Leonardo Bras
2020-06-26 15:23 ` Leonardo Bras
2020-06-26 17:55 ` Leonardo Bras
2020-07-01 8:16 ` Alexey Kardashevskiy
2020-07-01 19:57 ` Leonardo Bras
2020-07-01 23:48 ` Leonardo Bras
2020-07-02 0:31 ` Alexey Kardashevskiy
2020-07-02 0:54 ` Leonardo Bras
2020-07-03 6:27 ` Leonardo Bras
2020-06-24 6:24 ` [PATCH v2 6/6] powerpc/pseries/iommu: Avoid errors when DDW starts at 0x00 Leonardo Bras
2020-06-26 17:46 ` Leonardo Bras
2020-07-01 8:04 ` Alexey Kardashevskiy
2020-07-01 19:59 ` Leonardo Bras
2020-06-24 15:54 ` [PATCH v2 0/6] Remove default DMA window before creating DDW Leonardo Bras
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