[PATCH] mtd: nand: Make sure drivers not supporting SET/GET_FEATURES return -ENOTSUPP

Boris Brezillon boris.brezillon at free-electrons.com
Fri May 26 08:10:15 PDT 2017


A lot of drivers are providing their own ->cmdfunc(), and most of the
time this implementation does not support all possible NAND operations.
But since ->cmdfunc() cannot return an error code, the core has no way
to know that the operation it requested is not supported.

This is a problem we cannot address for all kind of operations with the
current design, but we can prevent these silent failures for the
GET/SET FEATURES operation by overloading the default
->onfi_{set,get}_features() methods with one returning -ENOTSUPP.

Reported-by: Chris Packham <Chris.Packham at alliedtelesis.co.nz>
Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---

This bug has been discovered by Chris while testing linux-next on his
marvell platform (which is using pxa3xx NAND controller driver).
The bug was caused by commit b566d9c055de ("mtd: nand: add support for
Micron on-die ECC") which is using ->set/get_features() to detect
whether the NAND supports on-die ECC or not.

This reveals how fragile the current ->cmdfunc() interface is. Not only
->cmdfunc() cannot return an error code, but even if it could, most of
the time, learning that a specific operation is not supported when
trying to execute it is already too late.

Anyway, this is not something we can address immediately (I'm working
on a new ->exec_op()/->supports_op() interface that will hopefully
address the aforementioned problems), but I guess this fix can serve as
a reference to show that overloading ->cmdfunc() is a really bad idea
and that ->cmd_ctrl() should be implemented instead, unless it's proven
to be impossible.

Note that I didn't add a Fixes tag because I plan to rearrange my
nand/next branch to put this commit before b566d9c055de to avoid
breaking bisectability.
---
 drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c  |  2 ++
 drivers/mtd/nand/cafe_nand.c                  |  2 ++
 drivers/mtd/nand/denali.c                     |  2 ++
 drivers/mtd/nand/docg4.c                      |  2 ++
 drivers/mtd/nand/fsl_elbc_nand.c              |  2 ++
 drivers/mtd/nand/fsl_ifc_nand.c               |  2 ++
 drivers/mtd/nand/hisi504_nand.c               |  2 ++
 drivers/mtd/nand/mpc5121_nfc.c                |  2 ++
 drivers/mtd/nand/nand_base.c                  | 19 +++++++++++++++++++
 drivers/mtd/nand/pxa3xx_nand.c                |  2 ++
 drivers/mtd/nand/qcom_nandc.c                 |  2 ++
 drivers/mtd/nand/sh_flctl.c                   |  2 ++
 drivers/mtd/nand/vf610_nfc.c                  |  2 ++
 drivers/staging/mt29f_spinand/mt29f_spinand.c |  2 ++
 include/linux/mtd/nand.h                      |  5 +++++
 15 files changed, 50 insertions(+)

diff --git a/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c b/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
index f1da4ea88f2c..54bac5b73f0a 100644
--- a/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
+++ b/drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c
@@ -392,6 +392,8 @@ int bcm47xxnflash_ops_bcm4706_init(struct bcm47xxnflash *b47n)
 	b47n->nand_chip.read_byte = bcm47xxnflash_ops_bcm4706_read_byte;
 	b47n->nand_chip.read_buf = bcm47xxnflash_ops_bcm4706_read_buf;
 	b47n->nand_chip.write_buf = bcm47xxnflash_ops_bcm4706_write_buf;
+	b47n->nand_chip.onfi_set_features = nand_onfi_get_set_features_notsupp;
+	b47n->nand_chip.onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	nand_chip->chip_delay = 50;
 	b47n->nand_chip.bbt_options = NAND_BBT_USE_FLASH;
diff --git a/drivers/mtd/nand/cafe_nand.c b/drivers/mtd/nand/cafe_nand.c
index d40c32d311d8..2fd733eba0a3 100644
--- a/drivers/mtd/nand/cafe_nand.c
+++ b/drivers/mtd/nand/cafe_nand.c
@@ -654,6 +654,8 @@ static int cafe_nand_probe(struct pci_dev *pdev,
 	cafe->nand.read_buf = cafe_read_buf;
 	cafe->nand.write_buf = cafe_write_buf;
 	cafe->nand.select_chip = cafe_select_chip;
+	cafe->nand.onfi_set_features = nand_onfi_get_set_features_notsupp;
+	cafe->nand.onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	cafe->nand.chip_delay = 0;
 
diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 16634df2e39a..b3c99d98fdee 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -1531,6 +1531,8 @@ int denali_init(struct denali_nand_info *denali)
 	chip->cmdfunc = denali_cmdfunc;
 	chip->read_byte = denali_read_byte;
 	chip->waitfunc = denali_waitfunc;
+	chip->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	/*
 	 * scan for NAND devices attached to the controller
diff --git a/drivers/mtd/nand/docg4.c b/drivers/mtd/nand/docg4.c
index 7af2a3cd949e..a27a84fbfb84 100644
--- a/drivers/mtd/nand/docg4.c
+++ b/drivers/mtd/nand/docg4.c
@@ -1260,6 +1260,8 @@ static void __init init_mtd_structs(struct mtd_info *mtd)
 	nand->read_buf = docg4_read_buf;
 	nand->write_buf = docg4_write_buf16;
 	nand->erase = docg4_erase_block;
+	nand->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	nand->onfi_get_features = nand_onfi_get_set_features_notsupp;
 	nand->ecc.read_page = docg4_read_page;
 	nand->ecc.write_page = docg4_write_page;
 	nand->ecc.read_page_raw = docg4_read_page_raw;
diff --git a/drivers/mtd/nand/fsl_elbc_nand.c b/drivers/mtd/nand/fsl_elbc_nand.c
index 113f76e59937..b9ac16f05057 100644
--- a/drivers/mtd/nand/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -775,6 +775,8 @@ static int fsl_elbc_chip_init(struct fsl_elbc_mtd *priv)
 	chip->select_chip = fsl_elbc_select_chip;
 	chip->cmdfunc = fsl_elbc_cmdfunc;
 	chip->waitfunc = fsl_elbc_wait;
+	chip->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	chip->bbt_td = &bbt_main_descr;
 	chip->bbt_md = &bbt_mirror_descr;
diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
index d1570f512f0b..89e14daeaba6 100644
--- a/drivers/mtd/nand/fsl_ifc_nand.c
+++ b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -831,6 +831,8 @@ static int fsl_ifc_chip_init(struct fsl_ifc_mtd *priv)
 	chip->select_chip = fsl_ifc_select_chip;
 	chip->cmdfunc = fsl_ifc_cmdfunc;
 	chip->waitfunc = fsl_ifc_wait;
+	chip->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	chip->bbt_td = &bbt_main_descr;
 	chip->bbt_md = &bbt_mirror_descr;
diff --git a/drivers/mtd/nand/hisi504_nand.c b/drivers/mtd/nand/hisi504_nand.c
index e40364eeb556..530caa80b1b6 100644
--- a/drivers/mtd/nand/hisi504_nand.c
+++ b/drivers/mtd/nand/hisi504_nand.c
@@ -764,6 +764,8 @@ static int hisi_nfc_probe(struct platform_device *pdev)
 	chip->write_buf		= hisi_nfc_write_buf;
 	chip->read_buf		= hisi_nfc_read_buf;
 	chip->chip_delay	= HINFC504_CHIP_DELAY;
+	chip->onfi_set_features	= nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features	= nand_onfi_get_set_features_notsupp;
 
 	hisi_nfc_host_init(host);
 
diff --git a/drivers/mtd/nand/mpc5121_nfc.c b/drivers/mtd/nand/mpc5121_nfc.c
index 6d6eaed2d20c..0e86fb6277c3 100644
--- a/drivers/mtd/nand/mpc5121_nfc.c
+++ b/drivers/mtd/nand/mpc5121_nfc.c
@@ -708,6 +708,8 @@ static int mpc5121_nfc_probe(struct platform_device *op)
 	chip->read_buf = mpc5121_nfc_read_buf;
 	chip->write_buf = mpc5121_nfc_write_buf;
 	chip->select_chip = mpc5121_nfc_select_chip;
+	chip->onfi_set_features	= nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features	= nand_onfi_get_set_features_notsupp;
 	chip->bbt_options = NAND_BBT_USE_FLASH;
 	chip->ecc.mode = NAND_ECC_SOFT;
 	chip->ecc.algo = NAND_ECC_HAMMING;
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 54a1dfa327ff..d6fb4a139387 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3424,6 +3424,25 @@ static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip,
 }
 
 /**
+ * nand_onfi_get_set_features_notsupp - set/get features stub returning
+ *					-ENOTSUPP
+ * @mtd: MTD device structure
+ * @chip: nand chip info structure
+ * @addr: feature address.
+ * @subfeature_param: the subfeature parameters, a four bytes array.
+ *
+ * Should be used by NAND controller drivers that do not support the SET/GET
+ * FEATURES operations.
+ */
+int nand_onfi_get_set_features_notsupp(struct mtd_info *mtd,
+				       struct nand_chip *chip,
+				       int feature_addr, u8 *subfeature_para)
+{
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL(nand_onfi_get_set_features_notsupp);
+
+/**
  * nand_suspend - [MTD Interface] Suspend the NAND flash
  * @mtd: MTD device structure
  */
diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index 649ba8200832..74dae4bbdac8 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -1812,6 +1812,8 @@ static int alloc_nand_resource(struct platform_device *pdev)
 		chip->write_buf		= pxa3xx_nand_write_buf;
 		chip->options		|= NAND_NO_SUBPAGE_WRITE;
 		chip->cmdfunc		= nand_cmdfunc;
+		chip->onfi_set_features	= nand_onfi_get_set_features_notsupp;
+		chip->onfi_get_features	= nand_onfi_get_set_features_notsupp;
 	}
 
 	nand_hw_control_init(chip->controller);
diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
index 57d483ac5765..88af7145a51a 100644
--- a/drivers/mtd/nand/qcom_nandc.c
+++ b/drivers/mtd/nand/qcom_nandc.c
@@ -2008,6 +2008,8 @@ static int qcom_nand_host_init(struct qcom_nand_controller *nandc,
 	chip->read_byte		= qcom_nandc_read_byte;
 	chip->read_buf		= qcom_nandc_read_buf;
 	chip->write_buf		= qcom_nandc_write_buf;
+	chip->onfi_set_features	= nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features	= nand_onfi_get_set_features_notsupp;
 
 	/*
 	 * the bad block marker is readable only when we read the last codeword
diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index 442ce619b3b6..891ac7b99305 100644
--- a/drivers/mtd/nand/sh_flctl.c
+++ b/drivers/mtd/nand/sh_flctl.c
@@ -1183,6 +1183,8 @@ static int flctl_probe(struct platform_device *pdev)
 	nand->read_buf = flctl_read_buf;
 	nand->select_chip = flctl_select_chip;
 	nand->cmdfunc = flctl_cmdfunc;
+	nand->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	nand->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	if (pdata->flcmncr_val & SEL_16BIT)
 		nand->options |= NAND_BUSWIDTH_16;
diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c
index 3ea4bb19e12d..744ab10e8962 100644
--- a/drivers/mtd/nand/vf610_nfc.c
+++ b/drivers/mtd/nand/vf610_nfc.c
@@ -703,6 +703,8 @@ static int vf610_nfc_probe(struct platform_device *pdev)
 	chip->read_buf = vf610_nfc_read_buf;
 	chip->write_buf = vf610_nfc_write_buf;
 	chip->select_chip = vf610_nfc_select_chip;
+	chip->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	chip->options |= NAND_NO_SUBPAGE_WRITE;
 
diff --git a/drivers/staging/mt29f_spinand/mt29f_spinand.c b/drivers/staging/mt29f_spinand/mt29f_spinand.c
index e389009fca42..a4e3ae8f0c85 100644
--- a/drivers/staging/mt29f_spinand/mt29f_spinand.c
+++ b/drivers/staging/mt29f_spinand/mt29f_spinand.c
@@ -915,6 +915,8 @@ static int spinand_probe(struct spi_device *spi_nand)
 	chip->waitfunc	= spinand_wait;
 	chip->options	|= NAND_CACHEPRG;
 	chip->select_chip = spinand_select_chip;
+	chip->onfi_set_features = nand_onfi_get_set_features_notsupp;
+	chip->onfi_get_features = nand_onfi_get_set_features_notsupp;
 
 	mtd = nand_to_mtd(chip);
 
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index f01991649118..5388c07836fd 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -1261,6 +1261,11 @@ int nand_read_oob_std(struct mtd_info *mtd, struct nand_chip *chip, int page);
 int nand_read_oob_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
 			   int page);
 
+/* Stub used by drivers that do not support GET/SET FEATURES operations */
+int nand_onfi_get_set_features_notsupp(struct mtd_info *mtd,
+				       struct nand_chip *chip,
+				       int feature_addr, u8 *subfeature_para);
+
 /* Default read_page_raw implementation */
 int nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
 		       uint8_t *buf, int oob_required, int page);
-- 
2.11.0




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