From: Christoph Hellwig <hch@lst.de>
To: Guo Ren <guoren@kernel.org>
Cc: "Christoph Hellwig" <hch@lst.de>,
"Nick Kossifidis" <mick@ics.forth.gr>,
"Drew Fustini" <drew@beagleboard.org>,
"Anup Patel" <anup.patel@wdc.com>,
"Palmer Dabbelt" <palmerdabbelt@google.com>,
wefu@redhat.com, "Wei Wu (吴伟)" <lazyparser@gmail.com>,
linux-riscv <linux-riscv@lists.infradead.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
linux-sunxi@lists.linux.dev, "Guo Ren" <guoren@linux.alibaba.com>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Benjamin Koch" <snowball@c3pb.de>,
"Matteo Croce" <mcroce@linux.microsoft.com>,
"Wei Fu" <tekkamanninja@gmail.com>
Subject: Re: [PATCH RFC 0/3] riscv: Add DMA_COHERENT support
Date: Mon, 7 Jun 2021 08:51:08 +0200 [thread overview]
Message-ID: <20210607065108.GA24872@lst.de> (raw)
In-Reply-To: <CAJF2gTRZuER5YbTD=0xWLU0Np6eD8L_z3rZH0i_WXgENUD3nbQ@mail.gmail.com>
On Mon, Jun 07, 2021 at 02:41:14PM +0800, Guo Ren wrote:
> Double/Triple the size of physical memory regions can't be accepted by
> SOC vendors, because it wastes HW resources.
> Some cost-down soc interconnects only have 32bit~34bit width of
> physical address, are you sure you could force them to expand it? (I
> can't)
>
> > or somewhat dynamic.
> How can HW implement with dynamic modifying PMA? What's the granularity?
I'm just stating the requirements from the Linux DMA perspective. You
also do not need tripple the address space, just double.
next prev parent reply other threads:[~2021-06-07 6:51 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 5:04 [PATCH RFC 0/3] riscv: Add DMA_COHERENT support guoren
2021-05-19 5:04 ` [PATCH RFC 1/3] riscv: pgtable.h: Fixup _PAGE_CHG_MASK usage guoren
2021-05-19 5:04 ` [PATCH RFC 2/3] riscv: Add DMA_COHERENT for custom PTE attributes guoren
2021-05-19 5:04 ` [PATCH RFC 3/3] riscv: Add SYNC_DMA_FOR_CPU/DEVICE for DMA_COHERENT guoren
2021-05-19 6:32 ` Guo Ren
2021-05-19 5:20 ` [PATCH RFC 0/3] riscv: Add DMA_COHERENT support Christoph Hellwig
2021-05-19 5:48 ` Guo Ren
2021-05-19 5:55 ` Christoph Hellwig
2021-05-19 6:09 ` Guo Ren
2021-05-19 6:44 ` Drew Fustini
2021-05-19 6:53 ` Christoph Hellwig
2021-05-20 1:45 ` Guo Ren
2021-05-20 5:48 ` Christoph Hellwig
2021-06-06 18:14 ` Nick Kossifidis
2021-06-07 0:04 ` Guo Ren
2021-06-07 2:16 ` Nick Kossifidis
2021-06-07 3:19 ` Guo Ren
2021-06-07 6:27 ` Christoph Hellwig
2021-06-07 6:41 ` Guo Ren
2021-06-07 6:51 ` Christoph Hellwig [this message]
2021-06-07 7:46 ` Guo Ren
2021-06-08 15:00 ` David Laight
2021-06-08 15:32 ` 'Christoph Hellwig'
2021-06-08 16:11 ` David Laight
2021-06-07 8:35 ` Nick Kossifidis
2021-06-09 3:28 ` Guo Ren
2021-06-09 6:05 ` Jisheng Zhang
2021-06-09 9:45 ` Nick Kossifidis
2021-06-09 12:43 ` Guo Ren
2021-05-19 6:05 ` Guo Ren
2021-05-19 6:06 ` Christoph Hellwig
2021-05-19 6:11 ` Guo Ren
2021-05-19 6:54 ` Drew Fustini
2021-05-19 6:56 ` Christoph Hellwig
2021-05-19 7:14 ` Anup Patel
2021-05-19 8:25 ` Damien Le Moal
2021-05-20 1:47 ` Guo Ren
2021-05-20 1:59 ` Guo Ren
2021-05-22 0:36 ` Guo Ren
2021-05-30 0:30 ` Palmer Dabbelt
2021-06-03 4:13 ` Palmer Dabbelt
2021-06-03 6:00 ` Anup Patel
2021-06-03 15:39 ` Palmer Dabbelt
2021-06-04 9:02 ` David Laight
2021-06-04 9:53 ` Arnd Bergmann
2021-06-04 14:47 ` Guo Ren
2021-06-04 16:12 ` Palmer Dabbelt
2021-06-04 21:26 ` Arnd Bergmann
2021-06-04 22:10 ` Palmer Dabbelt
2021-06-08 12:26 ` Guo Ren
2021-06-06 17:11 ` Guo Ren
2021-06-07 3:38 ` Anup Patel
2021-06-07 4:22 ` Guo Ren
2021-06-07 4:47 ` Anup Patel
2021-06-07 5:08 ` Guo Ren
2021-06-07 5:13 ` Guo Ren
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