From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3D61C719.4050607@embeddededge.com> Date: Tue, 20 Aug 2002 00:35:37 -0400 From: Dan Malek MIME-Version: 1.0 To: kas turi , linuxppc-embedded@lists.linuxppc.org Subject: Re: BD allocation and IDMA driver question References: <20020820033306.23695.qmail@web21006.mail.yahoo.com> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: kas turi wrote: > I would like to know what is the difference between > m8260_cpm_hostalloc and m8260_dp_alloc. The 'hostalloc' allocates from a small pool of host memory. This is usually used for small FIFOs as there is only a page or so for use by the entire system. The 'dp_alloc' allocates from the CPM dual ported memory. > .... The FCC driver > uses the former API and the serial driver uses the > latter API. If you would read the comment in the FCC driver, you may understand why :-) > ..... When I try to use m8260_cpm_hostalloc to > allocate buffer descriptor for the SPI driver the > timesys 2.4 kernel hangs. When I use m8260_dp_alloc > the SPI driver works. The 'hostalloc' returns a kernel virtual address. You have to convert this to a physical address for the CPM DMA. > Has anybody developed a IDMA driver for 8260 for 2.4 > kernel? There have been discussions about it on this mailing list. You may wish to search the archives for more information. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/