From: Leonardo Bras <leobras.c@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Leonardo Bras <leobras.c@gmail.com>,
Joel Stanley <joel@jms.id.au>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Nayna Jain <nayna@linux.ibm.com>,
Eric Richter <erichte@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>,
Hari Bathini <hbathini@linux.ibm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Brian King <brking@linux.vnet.ibm.com>,
Murilo Fossa Vicentini <muvic@linux.ibm.com>,
David Dai <zdai@linux.vnet.ibm.com>,
Matthew Wilcox <willy@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 1/2] dma-direction: Add DMA_DIR_COMPAT() macro to test direction compability
Date: Mon, 31 Aug 2020 15:48:58 -0300 [thread overview]
Message-ID: <20200831184859.110660-2-leobras.c@gmail.com> (raw)
In-Reply-To: <20200831184859.110660-1-leobras.c@gmail.com>
Given a existing mapping with 'current' direction, and a 'wanted'
direction for using that mapping, check if 'wanted' is satisfied by
'current'.
current accepts
DMA_BIDIRECTIONAL DMA_BIDIRECTIONAL, DMA_TO_DEVICE,
DMA_FROM_DEVICE, DMA_NONE
DMA_TO_DEVICE DMA_TO_DEVICE, DMA_NONE
DMA_FROM_DEVICE DMA_FROM_DEVICE, DMA_NONE
DMA_NONE DMA_NONE
This macro is useful for checking if a DMA mapping can be reused.
Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
include/linux/dma-direction.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/dma-direction.h b/include/linux/dma-direction.h
index 9c96e30e6a0b..caf3943a21f4 100644
--- a/include/linux/dma-direction.h
+++ b/include/linux/dma-direction.h
@@ -9,4 +9,7 @@ enum dma_data_direction {
DMA_NONE = 3,
};
+/* Checks if wanted direction is satisfied by current mapping direction*/
+#define DMA_DIR_COMPAT(current, wanted) (((current) & ~(wanted)) == 0)
+
#endif
--
2.25.4
next prev parent reply other threads:[~2020-08-31 18:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 18:48 [RFC PATCH 0/2] DMA pagecache Leonardo Bras
2020-08-31 18:48 ` Leonardo Bras [this message]
2020-08-31 18:48 ` [RFC PATCH 2/2] powerpc/kernel/iommu: Introduce IOMMU " Leonardo Bras
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200831184859.110660-2-leobras.c@gmail.com \
--to=leobras.c@gmail.com \
--cc=benh@kernel.crashing.org \
--cc=brking@linux.vnet.ibm.com \
--cc=christophe.leroy@c-s.fr \
--cc=erichte@linux.ibm.com \
--cc=hbathini@linux.ibm.com \
--cc=joel@jms.id.au \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=masahiroy@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=muvic@linux.ibm.com \
--cc=nayna@linux.ibm.com \
--cc=npiggin@gmail.com \
--cc=paulus@samba.org \
--cc=willy@infradead.org \
--cc=zdai@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox