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Message-ID: <20170525101256.GA12183@intel.com>
Date: Thu, 25 May 2017 18:12:57 +0800
From: "Du, Changbin" <changbin.du@...el.com>
To: linux-pci@...r.kernel.org
Cc: changbin.du@...el.com, linux-kernel@...r.kernel.org
Subject: [Q] What about PCI mmio access alignment?
Hi, guys,
I have a basic quesion about the alignment when access PCI bar mmio space. Is
the address accessed must be DW aligned and count must be DW aligned?
As far as I know, The address field of TLB ignore lower 2 bits and the unit of
length field also is DW. So does it mean above question is Yes? Else will CPU
handle unaligned access for mmio space?
I want to know wether below access illegal or not:
- readb(bar0)
- readb(bar0 + 1)
- readl(bar0)
Thanks,
Changbin Du
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