mirror of https://github.com/hak5/openwrt-owl.git
65 lines
2.2 KiB
Diff
65 lines
2.2 KiB
Diff
|
From 67a9ad9b8a6f6ea76ef8fc484ae49970d72d5534 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
|
||
|
|
Date: Wed, 14 May 2014 14:58:06 -0300
|
||
|
|
Subject: mtd: nand: Warn the user if the selected ECC strength is too weak
|
||
|
|
|
||
|
|
This commit makes use of the chip->ecc_strength_ds and chip->ecc_step_ds which
|
||
|
|
contain the datasheet minimum requested ECC strength to produce a noisy warning
|
||
|
|
if the configured ECC strength is weaker.
|
||
|
|
|
||
|
|
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
|
||
|
|
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
|
||
|
|
|
||
|
|
--- a/drivers/mtd/nand/nand_base.c
|
||
|
|
+++ b/drivers/mtd/nand/nand_base.c
|
||
|
|
@@ -3682,6 +3682,39 @@ int nand_scan_ident(struct mtd_info *mtd
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(nand_scan_ident);
|
||
|
|
|
||
|
|
+/*
|
||
|
|
+ * Check if the chip configuration meet the datasheet requirements.
|
||
|
|
+
|
||
|
|
+ * If our configuration corrects A bits per B bytes and the minimum
|
||
|
|
+ * required correction level is X bits per Y bytes, then we must ensure
|
||
|
|
+ * both of the following are true:
|
||
|
|
+ *
|
||
|
|
+ * (1) A / B >= X / Y
|
||
|
|
+ * (2) A >= X
|
||
|
|
+ *
|
||
|
|
+ * Requirement (1) ensures we can correct for the required bitflip density.
|
||
|
|
+ * Requirement (2) ensures we can correct even when all bitflips are clumped
|
||
|
|
+ * in the same sector.
|
||
|
|
+ */
|
||
|
|
+static bool nand_ecc_strength_good(struct mtd_info *mtd)
|
||
|
|
+{
|
||
|
|
+ struct nand_chip *chip = mtd->priv;
|
||
|
|
+ struct nand_ecc_ctrl *ecc = &chip->ecc;
|
||
|
|
+ int corr, ds_corr;
|
||
|
|
+
|
||
|
|
+ if (ecc->size == 0 || chip->ecc_step_ds == 0)
|
||
|
|
+ /* Not enough information */
|
||
|
|
+ return true;
|
||
|
|
+
|
||
|
|
+ /*
|
||
|
|
+ * We get the number of corrected bits per page to compare
|
||
|
|
+ * the correction density.
|
||
|
|
+ */
|
||
|
|
+ corr = (mtd->writesize * ecc->strength) / ecc->size;
|
||
|
|
+ ds_corr = (mtd->writesize * chip->ecc_strength_ds) / chip->ecc_step_ds;
|
||
|
|
+
|
||
|
|
+ return corr >= ds_corr && ecc->strength >= chip->ecc_strength_ds;
|
||
|
|
+}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* nand_scan_tail - [NAND Interface] Scan for the NAND device
|
||
|
|
@@ -3891,6 +3924,9 @@ int nand_scan_tail(struct mtd_info *mtd)
|
||
|
|
ecc->layout->oobavail += ecc->layout->oobfree[i].length;
|
||
|
|
mtd->oobavail = ecc->layout->oobavail;
|
||
|
|
|
||
|
|
+ /* ECC sanity check: warn noisily if it's too weak */
|
||
|
|
+ WARN_ON(!nand_ecc_strength_good(mtd));
|
||
|
|
+
|
||
|
|
/*
|
||
|
|
* Set the number of read / write steps for one page depending on ECC
|
||
|
|
* mode.
|