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H A D | mtk_nand.c | e1884ffd Tue May 07 05:25:38 CDT 2019 Xiaolei Li <xiaolei.li@mediatek.com> mtd: rawnand: mtk: Correct low level time calculation of r/w cycle
At present, the flow of calculating AC timing of read/write cycle in SDR mode is that: At first, calculate high hold time which is valid for both read and write cycle using the max value between tREH_min and tWH_min. Secondly, calculate WE# pulse width using tWP_min. Thridly, calculate RE# pulse width using the bigger one between tREA_max and tRP_min.
But NAND SPEC shows that Controller should also meet write/read cycle time. That is write cycle time should be more than tWC_min and read cycle should be more than tRC_min. Obviously, we do not achieve that now.
This patch corrects the low level time calculation to meet minimum read/write cycle time required. After getting the high hold time, WE# low level time will be promised to meet tWP_min and tWC_min requirement, and RE# low level time will be promised to meet tREA_max, tRP_min and tRC_min requirement.
Fixes: edfee3619c49 ("mtd: nand: mtk: add ->setup_data_interface() hook") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> e1884ffd Tue May 07 05:25:38 CDT 2019 Xiaolei Li <xiaolei.li@mediatek.com> mtd: rawnand: mtk: Correct low level time calculation of r/w cycle At present, the flow of calculating AC timing of read/write cycle in SDR mode is that: At first, calculate high hold time which is valid for both read and write cycle using the max value between tREH_min and tWH_min. Secondly, calculate WE# pulse width using tWP_min. Thridly, calculate RE# pulse width using the bigger one between tREA_max and tRP_min. But NAND SPEC shows that Controller should also meet write/read cycle time. That is write cycle time should be more than tWC_min and read cycle should be more than tRC_min. Obviously, we do not achieve that now. This patch corrects the low level time calculation to meet minimum read/write cycle time required. After getting the high hold time, WE# low level time will be promised to meet tWP_min and tWC_min requirement, and RE# low level time will be promised to meet tREA_max, tRP_min and tRC_min requirement. Fixes: edfee3619c49 ("mtd: nand: mtk: add ->setup_data_interface() hook") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
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