From: Armin Kuster <akuster@mvista•com>
To: Roman Zippel <zippel@linux-m68k•org>
Cc: ppcdevel <linuxppc-dev@lists•linuxppc.org>
Subject: Re: New API for non cache coherent ppc cpu's
Date: Wed, 21 Nov 2001 10:29:11 -0800 [thread overview]
Message-ID: <3BFBF277.A05245D6@mvista.com> (raw)
In-Reply-To: Pine.LNX.4.33.0111211152230.6681-100000@serv
Roman Zippel wrote:
>
> Hi,
>
> On Tue, 20 Nov 2001, Armin Kuster wrote:
>
> > About a month ago a new API made its way into the ppc,
> > consistent_sync_page.
>
> Another one?
> We have now 3 APIs for this:
> - cache_(push|clear): that's the old m68k API (and also used by APUS)
> - dma_cache_(inv|wback|wback_inv): used by mips(64), parisc, sh
> - consistent_sync_page: ppc
>
> > For CONFIG_NOT_COHERENT_CACHE processors,
> > requires
> > proper flushing of the page being used. Please review and provide feed
> > back
>
> Two comments:
> - I'm not sure about the page argument, although I'd like to see it, the
> problem is the drivers usually don't have a page pointer.
example as it is used today.
mapping = pci_map_page(pdev,
virt_to_page(cmd->request_buffer),
((unsigned long)cmd->request_buffer &
~PAGE_MASK),
cmd->request_bufflen, dma_dir);
/*
* pci_{map,unmap}_single_page maps a kernel page to a dma_addr_t.
identical
* to pci_map_single, but takes a struct page instead of a virtual
address
*/
static inline dma_addr_t pci_map_page(struct pci_dev *hwdev, struct page
*page,
unsigned long offset, size_t size,
int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
consistent_sync_page(page, offset, size, direction);
return (page - mem_map) * PAGE_SIZE + PCI_DRAM_OFFSET + offset;
}
> - I think it was never defined, what should be done if offset/size isn't
> cache line aligned. That's especially a problem in the invalidate only
> case. I'd prefer to make this illegal, as it's mostly not a problem for
> drivers.
>
wouldn't it also be a problem for consistent_sync? we don't check for
offset/size are cache line aligned.
> bye, Roman
-- armin
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2001-11-21 18:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-20 20:13 New API for non cache coherent ppc cpu's Armin Kuster
2001-11-21 11:15 ` Roman Zippel
2001-11-21 18:29 ` Armin Kuster [this message]
2001-11-21 20:20 ` Roman Zippel
2001-11-22 20:57 ` Paul Mackerras
2001-11-22 23:07 ` Dan Malek
2001-11-22 23:54 ` Roman Zippel
2001-11-23 1:32 ` Paul Mackerras
2001-11-23 16:08 ` Dan Malek
2001-11-22 23:50 ` Roman Zippel
2001-11-23 1:09 ` Paul Mackerras
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