mtd: nand: qcom: reorganize nand page write

Each NAND page consist of multiple codewords. Following is
sequence for NAND page write according to hardware guide.

1. Program Power-up configuration, page row, page column
   address and flash configuration registers.
2. Write NAND_FLASH_CMD followed by NANC_EXEC_CMD for each
   codeword.
3. Read NAND_FLASH_STATUS for each codeword.

The step 1 should be done once for each page and step 2,3 should
be done for each codeword.

Currently, all the 3 steps are being done for each codeword which
is wrong. Now this patch reorganizes page write functions to
configure page specific register once and per codeword specific
registers for each NAND ECC step.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/qcom_nandc.c

@@ -635,15 +635,24 @@ static void config_nand_single_cw_page_read(struct qcom_nand_controller *nandc)
 	config_nand_cw_read(nandc);
 }
 
-static void config_cw_write_pre(struct qcom_nand_controller *nandc)
+/*
+ * Helper to prepare DMA descriptors used to configure registers needed for
+ * before writing a NAND page.
+ */
+static void config_nand_page_write(struct qcom_nand_controller *nandc)
 {
-	write_reg_dma(nandc, NAND_FLASH_CMD, 3);
+	write_reg_dma(nandc, NAND_ADDR0, 2);
 	write_reg_dma(nandc, NAND_DEV0_CFG0, 3);
 	write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1);
 }
 
-static void config_cw_write_post(struct qcom_nand_controller *nandc)
+/*
+ * Helper to prepare DMA descriptors for configuring registers
+ * before writing each codeword in NAND page.
+ */
+static void config_nand_cw_write(struct qcom_nand_controller *nandc)
 {
+	write_reg_dma(nandc, NAND_FLASH_CMD, 1);
 	write_reg_dma(nandc, NAND_EXEC_CMD, 1);
 
 	read_reg_dma(nandc, NAND_FLASH_STATUS, 1);
@@ -1326,6 +1335,7 @@ static int qcom_nandc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 
 	host->use_ecc = true;
 	update_rw_regs(host, ecc->steps, false);
+	config_nand_page_write(nandc);
 
 	for (i = 0; i < ecc->steps; i++) {
 		int data_size, oob_size;
@@ -1339,7 +1349,6 @@ static int qcom_nandc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 			oob_size = ecc->bytes;
 		}
 
-		config_cw_write_pre(nandc);
 
 		write_data_dma(nandc, FLASH_BUF_ACC, data_buf, data_size);
 
@@ -1357,7 +1366,7 @@ static int qcom_nandc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
 				       oob_buf, oob_size);
 		}
 
-		config_cw_write_post(nandc);
+		config_nand_cw_write(nandc);
 
 		data_buf += data_size;
 		oob_buf += oob_size;
@@ -1390,6 +1399,7 @@ static int qcom_nandc_write_page_raw(struct mtd_info *mtd,
 
 	host->use_ecc = false;
 	update_rw_regs(host, ecc->steps, false);
+	config_nand_page_write(nandc);
 
 	for (i = 0; i < ecc->steps; i++) {
 		int data_size1, data_size2, oob_size1, oob_size2;
@@ -1408,8 +1418,6 @@ static int qcom_nandc_write_page_raw(struct mtd_info *mtd,
 			oob_size2 = host->ecc_bytes_hw + host->spare_bytes;
 		}
 
-		config_cw_write_pre(nandc);
-
 		write_data_dma(nandc, reg_off, data_buf, data_size1);
 		reg_off += data_size1;
 		data_buf += data_size1;
@@ -1425,7 +1433,7 @@ static int qcom_nandc_write_page_raw(struct mtd_info *mtd,
 		write_data_dma(nandc, reg_off, oob_buf, oob_size2);
 		oob_buf += oob_size2;
 
-		config_cw_write_post(nandc);
+		config_nand_cw_write(nandc);
 	}
 
 	ret = submit_descs(nandc);
@@ -1475,10 +1483,10 @@ static int qcom_nandc_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
 	set_address(host, host->cw_size * (ecc->steps - 1), page);
 	update_rw_regs(host, 1, false);
 
-	config_cw_write_pre(nandc);
+	config_nand_page_write(nandc);
 	write_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer,
 		       data_size + oob_size);
-	config_cw_write_post(nandc);
+	config_nand_cw_write(nandc);
 
 	ret = submit_descs(nandc);
 
@@ -1560,9 +1568,9 @@ static int qcom_nandc_block_markbad(struct mtd_info *mtd, loff_t ofs)
 	set_address(host, host->cw_size * (ecc->steps - 1), page);
 	update_rw_regs(host, 1, false);
 
-	config_cw_write_pre(nandc);
+	config_nand_page_write(nandc);
 	write_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, host->cw_size);
-	config_cw_write_post(nandc);
+	config_nand_cw_write(nandc);
 
 	ret = submit_descs(nandc);