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authorIonela Voinescu <ionela.voinescu@imgtec.com>2015-03-30 11:59:10 +0100
committerPatrick Georgi <pgeorgi@google.com>2015-04-22 08:59:44 +0200
commita2c4f9ee9fbedfe540145350b121f5ffb9ce0b67 (patch)
treebb7321ba545c5bc5079e68db85a8a25f25043e17 /documentation
parentd1a21d7d7182a40f06f8ec4ff216454fd3c8c1cc (diff)
downloadcoreboot-a2c4f9ee9fbedfe540145350b121f5ffb9ce0b67.tar.xz
imgtec/pistachio: DDR row/bank/column mapping
The DRAM configuration register, apart from holding the device density and width also has a rudimentary address mapping scheme. Currently this is set to the default Bank/Row/Column. This means that the memory is segmented into 8 chunks, each with a page detector. If all the activity is in one section of memory then the other 7 page detectors could be idle. Changing this to Row/Bank/Column would concatenate the page detectors meaning that all 8 could be used by a single initiator. This may not gain anything in a synthetic bandwidth test but could yield extra performance in a real world application or benchmark. BRANCH=none BUG=chrome-os-partner:37087 TEST=tested on Pistachio bring up board -> DDR initialized properly; all access to DDR works properly in Coreboot ramstage, Depthcharge and Linux; no performance tests were ran so far. Change-Id: I22d86bf3b679ed63884d7436d9d7bbaf1726f640 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: e852ed42afcdc2062a0037144bab723227cb1f1f Original-Change-Id: If90b0cf5ce86db5e3d6d362873d22d4269e3a49f Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com> Original-Reviewed-on: https://chromium-review.googlesource.com/264340 Original-Reviewed-by: James Hartley <james.hartley@imgtec.com> Original-Reviewed-by: David Hendricks <dhendrix@chromium.org> Reviewed-on: http://review.coreboot.org/9916 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
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