mtd: nand: denali: remove meaningless pipeline read-ahead operation
The pipeline read-ahead function of the Denali IP enables continuous reading from the device; while data is being read out by a CPU, the controller maintains additional commands for streaming data from the device. This will reduce the latency of the second page or later. This feature is obviously no help for per-page accessors of Linux NAND driver interface. In the current implementation, the pipeline command is issued to load a single page, then data are read out immediately. The use of the pipeline operation is not adding any advantage, but just adding complexity to the code. Remove. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
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@ -84,7 +84,6 @@ static inline struct denali_nand_info *mtd_to_denali(struct mtd_info *mtd)
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#define SPARE_ACCESS 0x41
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#define MAIN_ACCESS 0x42
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#define MAIN_SPARE_ACCESS 0x43
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#define PIPELINE_ACCESS 0x2000
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#define DENALI_READ 0
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#define DENALI_WRITE 0x100
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@ -683,15 +682,7 @@ static int denali_send_pipeline_cmd(struct denali_nand_info *denali,
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int access_type, int op)
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{
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int status = PASS;
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uint32_t page_count = 1;
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uint32_t addr, cmd, irq_status, irq_mask;
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if (op == DENALI_READ)
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irq_mask = INTR__LOAD_COMP;
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else if (op == DENALI_WRITE)
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irq_mask = 0;
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else
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BUG();
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uint32_t addr, cmd;
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setup_ecc_for_xfer(denali, ecc_en, transfer_spare);
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@ -714,35 +705,8 @@ static int denali_send_pipeline_cmd(struct denali_nand_info *denali,
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cmd = MODE_10 | addr;
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index_addr(denali, cmd, access_type);
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/*
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* page 33 of the NAND controller spec indicates we should not
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* use the pipeline commands in Spare area only mode.
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* So we don't.
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*/
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if (access_type == SPARE_ACCESS) {
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cmd = MODE_01 | addr;
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iowrite32(cmd, denali->flash_mem);
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} else {
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index_addr(denali, cmd,
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PIPELINE_ACCESS | op | page_count);
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/*
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* wait for command to be accepted
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* can always use status0 bit as the
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* mask is identical for each bank.
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*/
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irq_status = wait_for_irq(denali, irq_mask);
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if (irq_status == 0) {
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dev_err(denali->dev,
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"cmd, page, addr on timeout (0x%x, 0x%x, 0x%x)\n",
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cmd, denali->page, addr);
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status = FAIL;
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} else {
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cmd = MODE_01 | addr;
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iowrite32(cmd, denali->flash_mem);
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}
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}
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cmd = MODE_01 | addr;
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iowrite32(cmd, denali->flash_mem);
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}
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return status;
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}
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