[PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[Kamal Dasu]

Changing brcmnand_set_wp() prototype in prepration for refactoring the nand
write protect logic to add flash status byte check for the protection bit.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
 drivers/mtd/nand/brcmnand/brcmnand.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index 42ebd73..c7c4efe 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -765,11 +765,14 @@ enum {
 	CS_SELECT_AUTO_DEVICE_ID_CFG		= BIT(30),
 };
 
-static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en)
+static int brcmnand_set_wp(struct brcmnand_host *host, int en)
 {
+	struct brcmnand_controller *ctrl = host->ctrl;
 	u32 val = en ? CS_SELECT_NAND_WP : 0;
 
 	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
+
+	return 0;
 }
 
 /***********************************************************************
@@ -1029,7 +1032,7 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp)
 			dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off");
 			old_wp = wp;
 		}
-		brcmnand_set_wp(ctrl, wp);
+		brcmnand_set_wp(host, wp);
 	}
 }
 
@@ -2462,14 +2465,6 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 	/* Disable XOR addressing */
 	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_XOR, 0xff, 0, 0);
 
-	if (ctrl->features & BRCMNAND_HAS_WP) {
-		/* Permanently disable write protection */
-		if (wp_on == 2)
-			brcmnand_set_wp(ctrl, false);
-	} else {
-		wp_on = 0;
-	}
-
 	/* IRQ */
 	ctrl->irq = platform_get_irq(pdev, 0);
 	if ((int)ctrl->irq < 0) {
@@ -2522,6 +2517,18 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 			}
 
 			list_add_tail(&host->node, &ctrl->host_list);
+
+			if (ctrl->features & BRCMNAND_HAS_WP) {
+				/* Permanently disable write protection */
+				if (wp_on == 2) {
+					ret = brcmnand_set_wp(host, false);
+					if (ret)
+						goto err;
+				}
+			} else {
+				wp_on = 0;
+			}
+
 		}
 	}
 
-- 
1.9.1

[PATCH V4, 2/2] mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program

[Kamal Dasu]

brcmnand controller v6.x and v7.x lets driver to enable disable #WP pin
via NAND_WP bit in CS_SELECT register. Driver implementation assumes that
setting/resetting the bit would assert/de-assert  #WP pin instantaneously
from the flash part's perspective, and was proceeding to erase/program
without verifying flash status byte for protection bit. In rigorous
testing this was causing rare data corruptions with erase and/or
subsequent programming. To fix this check NAND status in addition to
controller #WP pin status to make sure both sides are ready to accept
new commands.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
 drivers/mtd/nand/brcmnand/brcmnand.c | 70 +++++++++++++++++++++++++++++++++---
 1 file changed, 65 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index c7c4efe..af32685 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -101,6 +101,9 @@ struct brcm_nand_dma_desc {
 #define BRCMNAND_MIN_BLOCKSIZE	(8 * 1024)
 #define BRCMNAND_MIN_DEVSIZE	(4ULL * 1024 * 1024)
 
+#define NAND_CTRL_RDY			(INTFC_CTLR_READY | INTFC_FLASH_READY)
+#define NAND_POLL_STATUS_TIMEOUT_MS	100
+
 /* Controller feature flags */
 enum {
 	BRCMNAND_HAS_1K_SECTORS			= BIT(0),
@@ -765,12 +768,69 @@ enum {
 	CS_SELECT_AUTO_DEVICE_ID_CFG		= BIT(30),
 };
 
-static int brcmnand_set_wp(struct brcmnand_host *host, int en)
+static int bcmnand_ctrl_poll_status(struct brcmnand_controller *ctrl,
+				    u32 mask, u32 expected_val,
+				    unsigned long timeout_ms)
+{
+	unsigned long limit;
+	u32 val;
+
+	if (!timeout_ms)
+		timeout_ms = NAND_POLL_STATUS_TIMEOUT_MS;
+
+	limit = jiffies + msecs_to_jiffies(timeout_ms);
+	do {
+		val = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
+		if ((val & mask) == expected_val)
+			return 0;
+
+		cpu_relax();
+	} while (time_after(limit, jiffies));
+
+	dev_warn(ctrl->dev, "timeout on status poll (expected %x got %x)\n",
+		 expected_val, val & mask);
+
+	return -ETIMEDOUT;
+}
+
+static inline void brcmnand_set_wp_reg(struct brcmnand_controller *ctrl, int en)
 {
-	struct brcmnand_controller *ctrl = host->ctrl;
 	u32 val = en ? CS_SELECT_NAND_WP : 0;
 
 	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
+}
+
+static int brcmnand_set_wp(struct brcmnand_host *host, int en)
+{
+	struct brcmnand_controller *ctrl = host->ctrl;
+	struct mtd_info *mtd = nand_to_mtd(&host->chip);
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	int ret;
+
+	/*
+	 * make sure ctrl/flash ready before and after
+	 * changing state of WP PIN
+	 */
+	ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY | NAND_STATUS_READY,
+				       NAND_CTRL_RDY | NAND_STATUS_READY, 0);
+	if (ret)
+		return ret;
+
+	brcmnand_set_wp_reg(ctrl, en);
+	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
+	/* NAND_STATUS_WP 0x00 = protected, 0x80 = not protected */
+	ret = bcmnand_ctrl_poll_status(ctrl,
+				       NAND_CTRL_RDY | NAND_STATUS_READY |
+				       NAND_STATUS_WP,
+				       NAND_CTRL_RDY | NAND_STATUS_READY |
+				       (en ? 0 : NAND_STATUS_WP), 0);
+
+	if (ret) {
+		dev_err_ratelimited(&host->pdev->dev,
+				    "nand #WP expected %s\n",
+				    en ? "On" : "Off");
+		return ret;
+	}
 
 	return 0;
 }
@@ -1160,15 +1220,15 @@ static irqreturn_t brcmnand_dma_irq(int irq, void *data)
 static void brcmnand_send_cmd(struct brcmnand_host *host, int cmd)
 {
 	struct brcmnand_controller *ctrl = host->ctrl;
-	u32 intfc;
+	int ret;
 
 	dev_dbg(ctrl->dev, "send native cmd %d addr_lo 0x%x\n", cmd,
 		brcmnand_read_reg(ctrl, BRCMNAND_CMD_ADDRESS));
 	BUG_ON(ctrl->cmd_pending != 0);
 	ctrl->cmd_pending = cmd;
 
-	intfc = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
-	WARN_ON(!(intfc & INTFC_CTLR_READY));
+	ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0);
+	WARN_ON(ret);
 
 	mb(); /* flush previous writes */
 	brcmnand_write_reg(ctrl, BRCMNAND_CMD_START,
-- 
1.9.1

Re: [PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[Marek Vasut]

On 02/28/2017 05:55 PM, Kamal Dasu wrote:
> Changing brcmnand_set_wp() prototype in prepration for refactoring the nand
> write protect logic to add flash status byte check for the protection bit.
> 
> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
> ---
>  drivers/mtd/nand/brcmnand/brcmnand.c | 27 +++++++++++++++++----------
>  1 file changed, 17 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
> index 42ebd73..c7c4efe 100644
> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
> @@ -765,11 +765,14 @@ enum {
>  	CS_SELECT_AUTO_DEVICE_ID_CFG		= BIT(30),
>  };
>  
> -static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en)
> +static int brcmnand_set_wp(struct brcmnand_host *host, int en)
>  {
> +	struct brcmnand_controller *ctrl = host->ctrl;
>  	u32 val = en ? CS_SELECT_NAND_WP : 0;
>  
>  	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
> +
> +	return 0;
>  }
>  
>  /***********************************************************************
> @@ -1029,7 +1032,7 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp)
>  			dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off");
>  			old_wp = wp;
>  		}
> -		brcmnand_set_wp(ctrl, wp);
> +		brcmnand_set_wp(host, wp);
>  	}
>  }
>  
> @@ -2462,14 +2465,6 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  	/* Disable XOR addressing */
>  	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_XOR, 0xff, 0, 0);
>  
> -	if (ctrl->features & BRCMNAND_HAS_WP) {
> -		/* Permanently disable write protection */
> -		if (wp_on == 2)
> -			brcmnand_set_wp(ctrl, false);
> -	} else {
> -		wp_on = 0;
> -	}
> -
>  	/* IRQ */
>  	ctrl->irq = platform_get_irq(pdev, 0);
>  	if ((int)ctrl->irq < 0) {
> @@ -2522,6 +2517,18 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  			}
>  
>  			list_add_tail(&host->node, &ctrl->host_list);
> +
> +			if (ctrl->features & BRCMNAND_HAS_WP) {
> +				/* Permanently disable write protection */
> +				if (wp_on == 2) {
> +					ret = brcmnand_set_wp(host, false);
> +					if (ret)
> +						goto err;
> +				}
> +			} else {
> +				wp_on = 0;
> +			}
> +

Would it be worth it to move this into separate function ? Or maybe make
brcmnand_set_wp() check for BRCMNAND_HAS_WP and only set the WP
if the controller is actually capable of that ? I think that might make
the code readability a bit better ...

>  		}
>  	}
>  
> 


-- 
Best regards,
Marek Vasut

Re: [PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[Kamal Dasu]

Marek,

On Tue, Feb 28, 2017 at 1:25 PM, Marek Vasut <marek.vasut@gmail.com> wrote:
> On 02/28/2017 05:55 PM, Kamal Dasu wrote:
>> Changing brcmnand_set_wp() prototype in prepration for refactoring the nand
>> write protect logic to add flash status byte check for the protection bit.
>>
>> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
>> ---
>>  drivers/mtd/nand/brcmnand/brcmnand.c | 27 +++++++++++++++++----------
>>  1 file changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
>> index 42ebd73..c7c4efe 100644
>> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
>> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
>> @@ -765,11 +765,14 @@ enum {
>>       CS_SELECT_AUTO_DEVICE_ID_CFG            = BIT(30),
>>  };
>>
>> -static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en)
>> +static int brcmnand_set_wp(struct brcmnand_host *host, int en)
>>  {
>> +     struct brcmnand_controller *ctrl = host->ctrl;
>>       u32 val = en ? CS_SELECT_NAND_WP : 0;
>>
>>       brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
>> +
>> +     return 0;
>>  }
>>
>>  /***********************************************************************
>> @@ -1029,7 +1032,7 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp)
>>                       dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off");
>>                       old_wp = wp;
>>               }
>> -             brcmnand_set_wp(ctrl, wp);
>> +             brcmnand_set_wp(host, wp);
>>       }
>>  }
>>
>> @@ -2462,14 +2465,6 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>>       /* Disable XOR addressing */
>>       brcmnand_rmw_reg(ctrl, BRCMNAND_CS_XOR, 0xff, 0, 0);
>>
>> -     if (ctrl->features & BRCMNAND_HAS_WP) {
>> -             /* Permanently disable write protection */
>> -             if (wp_on == 2)
>> -                     brcmnand_set_wp(ctrl, false);
>> -     } else {
>> -             wp_on = 0;
>> -     }
>> -
>>       /* IRQ */
>>       ctrl->irq = platform_get_irq(pdev, 0);
>>       if ((int)ctrl->irq < 0) {
>> @@ -2522,6 +2517,18 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>>                       }
>>
>>                       list_add_tail(&host->node, &ctrl->host_list);
>> +
>> +                     if (ctrl->features & BRCMNAND_HAS_WP) {
>> +                             /* Permanently disable write protection */
>> +                             if (wp_on == 2) {
>> +                                     ret = brcmnand_set_wp(host, false);
>> +                                     if (ret)
>> +                                             goto err;
>> +                             }
>> +                     } else {
>> +                             wp_on = 0;
>> +                     }
>> +
>
> Would it be worth it to move this into separate function ? Or maybe make
> brcmnand_set_wp() check for BRCMNAND_HAS_WP and only set the WP
> if the controller is actually capable of that ? I think that might make
> the code readability a bit better ...
>
>>               }
>>       }
>>
>>

The above code is called during the probe and only when the bootline
wants to permanently set the wp off( wp == 2)  hence structured that
way. I would prefer to leave it that way.

In all other cases there is already brcmand_wp(mtd_info *mtd, int wp)
checks and maintains the wp state.

>
> --
> Best regards,
> Marek Vasut

Thanks
Kamal

Re: [PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[Boris Brezillon]

On Tue, 28 Feb 2017 11:55:25 -0500
Kamal Dasu <kdasu.kdev@gmail.com> wrote:

> Changing brcmnand_set_wp() prototype in prepration for refactoring the nand
> write protect logic to add flash status byte check for the protection bit.
> 
> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
> ---
>  drivers/mtd/nand/brcmnand/brcmnand.c | 27 +++++++++++++++++----------
>  1 file changed, 17 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
> index 42ebd73..c7c4efe 100644
> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
> @@ -765,11 +765,14 @@ enum {
>  	CS_SELECT_AUTO_DEVICE_ID_CFG		= BIT(30),
>  };
>  
> -static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en)
> +static int brcmnand_set_wp(struct brcmnand_host *host, int en)
>  {
> +	struct brcmnand_controller *ctrl = host->ctrl;
>  	u32 val = en ? CS_SELECT_NAND_WP : 0;
>  
>  	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
> +
> +	return 0;
>  }
>  
>  /***********************************************************************
> @@ -1029,7 +1032,7 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp)
>  			dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off");
>  			old_wp = wp;
>  		}
> -		brcmnand_set_wp(ctrl, wp);
> +		brcmnand_set_wp(host, wp);
>  	}
>  }
>  
> @@ -2462,14 +2465,6 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  	/* Disable XOR addressing */
>  	brcmnand_rmw_reg(ctrl, BRCMNAND_CS_XOR, 0xff, 0, 0);
>  
> -	if (ctrl->features & BRCMNAND_HAS_WP) {
> -		/* Permanently disable write protection */
> -		if (wp_on == 2)
> -			brcmnand_set_wp(ctrl, false);
> -	} else {
> -		wp_on = 0;
> -	}
> -

	if (!(ctrl->features & BRCMNAND_HAS_WP))
		wp_on = 0;

>  	/* IRQ */
>  	ctrl->irq = platform_get_irq(pdev, 0);
>  	if ((int)ctrl->irq < 0) {
> @@ -2522,6 +2517,18 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  			}
>  
>  			list_add_tail(&host->node, &ctrl->host_list);
> +
> +			if (ctrl->features & BRCMNAND_HAS_WP) {
> +				/* Permanently disable write protection */
> +				if (wp_on == 2) {
> +					ret = brcmnand_set_wp(host, false);
> +					if (ret)
> +						goto err;
> +				}
> +			} else {
> +				wp_on = 0;
> +			}
> +

			/* Permanently disable write protection */
			if (wp_on == 2) {
				ret = brcmnand_set_wp(host, false);
				if (ret)
					goto err;
			}


>  		}
>  	}
>  

Re: [PATCH V4, 1/2] mtd: nand: brcmnand: Change brcmnand_set_wp() prototype

[Kamal Dasu]

Boris,

On Tue, Feb 28, 2017 at 5:05 PM, Boris Brezillon
<boris.brezillon@free-electrons.com> wrote:
> On Tue, 28 Feb 2017 11:55:25 -0500
> Kamal Dasu <kdasu.kdev@gmail.com> wrote:
>
>> Changing brcmnand_set_wp() prototype in prepration for refactoring the nand
>> write protect logic to add flash status byte check for the protection bit.
>>
>> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
>> ---
>>  drivers/mtd/nand/brcmnand/brcmnand.c | 27 +++++++++++++++++----------
>>  1 file changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
>> index 42ebd73..c7c4efe 100644
>> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
>> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
>> @@ -765,11 +765,14 @@ enum {
>>       CS_SELECT_AUTO_DEVICE_ID_CFG            = BIT(30),
>>  };
>>
>> -static inline void brcmnand_set_wp(struct brcmnand_controller *ctrl, bool en)
>> +static int brcmnand_set_wp(struct brcmnand_host *host, int en)
>>  {
>> +     struct brcmnand_controller *ctrl = host->ctrl;
>>       u32 val = en ? CS_SELECT_NAND_WP : 0;
>>
>>       brcmnand_rmw_reg(ctrl, BRCMNAND_CS_SELECT, CS_SELECT_NAND_WP, 0, val);
>> +
>> +     return 0;
>>  }
>>
>>  /***********************************************************************
>> @@ -1029,7 +1032,7 @@ static void brcmnand_wp(struct mtd_info *mtd, int wp)
>>                       dev_dbg(ctrl->dev, "WP %s\n", wp ? "on" : "off");
>>                       old_wp = wp;
>>               }
>> -             brcmnand_set_wp(ctrl, wp);
>> +             brcmnand_set_wp(host, wp);
>>       }
>>  }
>>
>> @@ -2462,14 +2465,6 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>>       /* Disable XOR addressing */
>>       brcmnand_rmw_reg(ctrl, BRCMNAND_CS_XOR, 0xff, 0, 0);
>>
>> -     if (ctrl->features & BRCMNAND_HAS_WP) {
>> -             /* Permanently disable write protection */
>> -             if (wp_on == 2)
>> -                     brcmnand_set_wp(ctrl, false);
>> -     } else {
>> -             wp_on = 0;
>> -     }
>> -
>
>         if (!(ctrl->features & BRCMNAND_HAS_WP))
>                 wp_on = 0;
>
>>       /* IRQ */
>>       ctrl->irq = platform_get_irq(pdev, 0);
>>       if ((int)ctrl->irq < 0) {
>> @@ -2522,6 +2517,18 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>>                       }
>>
>>                       list_add_tail(&host->node, &ctrl->host_list);
>> +
>> +                     if (ctrl->features & BRCMNAND_HAS_WP) {
>> +                             /* Permanently disable write protection */
>> +                             if (wp_on == 2) {
>> +                                     ret = brcmnand_set_wp(host, false);
>> +                                     if (ret)
>> +                                             goto err;
>> +                             }
>> +                     } else {
>> +                             wp_on = 0;
>> +                     }
>> +
>
>                         /* Permanently disable write protection */
>                         if (wp_on == 2) {
>                                 ret = brcmnand_set_wp(host, false);
>                                 if (ret)
>                                         goto err;
>                         }
>
>
>>               }
>>       }
>>
>

Let me rework this and send a new patch. Actually I just need to set
the controller wp bit and the wp value since I do not need to worry
about the status since we are not going to try and change the #WP at
all in this case when we send the erase/program command.
brcmnand_set_wp_reg() calling this should be sufficient during probe.