mtd: nand: support Micron READ RETRY

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=8429bb3975ef81c114cde4da111e64d224d19f83
Commit:     8429bb3975ef81c114cde4da111e64d224d19f83
Parent:     ba84fb5952af114e28ac82adcdef75297701ccc1
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Tue Dec 3 15:51:09 2013 -0800
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Mon Jan 13 23:13:05 2014 -0800

    mtd: nand: support Micron READ RETRY
    
    Micron provides READ RETRY support via the ONFI vendor-specific
    parameter block (to indicate how many read-retry modes are available)
    and the ONFI {GET,SET}_FEATURES commands with a vendor-specific feature
    address (to support reading/switching the current read-retry mode).
    
    The recommended sequence is as follows:
    
      1. Perform PAGE_READ operation
      2. If no ECC error, we are done
      3. Run SET_FEATURES with feature address 89h, mode 1
      4. Retry PAGE_READ operation
      5. If ECC error and there are remaining supported modes, increment the
         mode and return to step 3. Otherwise, this is a true ECC error.
      6. Run SET_FEATURES with feature address 89h, mode 0, to return to the
         default state.
    
    This patch implements the chip->setup_read_retry() callback for
    Micron and fills in the chip->read_retries.
    
    Tested on Micron MT29F32G08CBADA, which supports 8 read-retry modes.
    
    The Micron vendor-specific table was checked against the datasheets for
    the following Micron NAND:
    
    Needs retry   Cell-type    Part number          Vendor revision    Byte 180
    -----------   ---------    ----------------     ---------------    ------------
    No            SLC          MT29F16G08ABABA      1                  Reserved (0)
    No            MLC          MT29F32G08CBABA      1                  Reserved (0)
    No            SLC          MT29F1G08AACWP       1                  0
    Yes           MLC          MT29F32G08CBADA      1                  08h
    Yes           MLC          MT29F64G08CBABA      2                  08h
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Acked-by: Huang Shijie <b32955 at freescale.com>
---
 drivers/mtd/nand/nand_base.c | 27 +++++++++++++++++++++++++++
 include/linux/mtd/nand.h     |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 4c2f39f..b8c74cd 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2979,6 +2979,30 @@ ext_out:
 	return ret;
 }
 
+static int nand_setup_read_retry_micron(struct mtd_info *mtd, int retry_mode)
+{
+	struct nand_chip *chip = mtd->priv;
+	uint8_t feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
+
+	return chip->onfi_set_features(mtd, chip, ONFI_FEATURE_ADDR_READ_RETRY,
+			feature);
+}
+
+/*
+ * Configure chip properties from Micron vendor-specific ONFI table
+ */
+static void nand_onfi_detect_micron(struct nand_chip *chip,
+		struct nand_onfi_params *p)
+{
+	struct nand_onfi_vendor_micron *micron = (void *)p->vendor;
+
+	if (le16_to_cpu(p->vendor_revision) < 1)
+		return;
+
+	chip->read_retries = micron->read_retry_options;
+	chip->setup_read_retry = nand_setup_read_retry_micron;
+}
+
 /*
  * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
  */
@@ -3085,6 +3109,9 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 		pr_warn("Could not retrieve ONFI ECC requirements\n");
 	}
 
+	if (p->jedec_id == NAND_MFR_MICRON)
+		nand_onfi_detect_micron(chip, p);
+
 	return 1;
 }
 
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 267d61d..3080a8c 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -219,6 +219,9 @@ struct nand_chip;
 /* ONFI feature address */
 #define ONFI_FEATURE_ADDR_TIMING_MODE	0x1
 
+/* Vendor-specific feature address (Micron) */
+#define ONFI_FEATURE_ADDR_READ_RETRY	0x89
+
 /* ONFI subfeature parameters length */
 #define ONFI_SUBFEATURE_PARAM_LEN	4