From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert Herranz Date: Tue, 16 Mar 2010 05:58:41 +0000 Subject: Re: [PATCH v4 05/11] swiotlb: add swiotlb_set_default_size() Message-Id: <4B9F1E11.80201@yahoo.es> List-Id: References: <1268421166-4791-1-git-send-email-albert_herranz@yahoo.es> <1268421166-4791-6-git-send-email-albert_herranz@yahoo.es> <20100316104440Y.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20100316104440Y.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: FUJITA Tomonori , Benjamin Herrenschmidt Cc: linux-usb@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-ia64@vger.kernel.org FUJITA Tomonori wrote: > On Fri, 12 Mar 2010 20:12:40 +0100 > Albert Herranz wrote: > >> The current SWIOTLB code uses a default of 64MB for the IO TLB area. >> This size can be influenced using a kernel command line parameter "swiotlb". >> Unfortunately, the parsing of the kernel command line is done _after_ the >> swiotlb is initialized on some architectures. >> >> This patch adds a new function swiotlb_set_default_size() which can be used >> before swiotlb_init() to indicate the desired IO TLB area size in bytes. >> >> This will be used later to implement a smaller IO TLB on the Nintendo Wii >> video game console which just comes with 24MB + 64MB of RAM. >> >> CC: linuxppc-dev@lists.ozlabs.org >> CC: linux-kernel@vger.kernel.org >> CC: x86@kernel.org >> CC: linux-ia64@vger.kernel.org >> Signed-off-by: Albert Herranz >> --- >> include/linux/swiotlb.h | 2 ++ >> lib/swiotlb.c | 20 ++++++++++++++++++++ >> 2 files changed, 22 insertions(+), 0 deletions(-) > > Please fix the powerpc swiotlb initialization instead. > > Calling swiotlb_init() before parsing kernel parameters sounds > wrong. Any reasons why you can't fix it? > I think that this would be better asked by a PowerPC maintainer. Ben? If this is really a problem the swiotlb late init may be a solution too in this particular case. Thanks, Albert