diff mbox series

[RFC,v1] mtd: rawnand: meson: invalidate cache on polling ECC bit

Message ID d4ef0bd6-816e-f6fa-9385-f05f775f0ae2@sberdevices.ru (mailing list archive)
State New, archived
Headers show
Series [RFC,v1] mtd: rawnand: meson: invalidate cache on polling ECC bit | expand

Commit Message

Arseniy Krasnov March 13, 2023, 7:32 a.m. UTC
'info_buf' memory is cached and driver polls ECC bit in it. This bit
is set by the NAND controller. If 'usleep_range()' returns before device
sets this bit, 'info_buf' will be cached and driver won't see update of
this bit and will loop forever.

Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
 drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Arseniy Krasnov March 13, 2023, 7:36 a.m. UTC | #1
Hello,

we reproduced this problem on one of our boards. It triggers very rare
when 'usleep_range()' is present, but when sleeping is removed - it fires
always. I suppose problem is with caching, as 'info_buf' memory is mapped by
'dma_map_single()'.

Thanks, Arseniy

On 13.03.2023 10:32, Arseniy Krasnov wrote:
> 'info_buf' memory is cached and driver polls ECC bit in it. This bit
> is set by the NAND controller. If 'usleep_range()' returns before device
> sets this bit, 'info_buf' will be cached and driver won't see update of
> this bit and will loop forever.
> 
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> ---
>  drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> index 5ee01231ac4c..2c05c08a0eaf 100644
> --- a/drivers/mtd/nand/raw/meson_nand.c
> +++ b/drivers/mtd/nand/raw/meson_nand.c
> @@ -176,6 +176,7 @@ struct meson_nfc {
>  
>  	dma_addr_t daddr;
>  	dma_addr_t iaddr;
> +	u32 info_bytes;
>  
>  	unsigned long assigned_cs;
>  };
> @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
>  					 nfc->daddr, datalen, dir);
>  			return ret;
>  		}
> +		nfc->info_bytes = infolen;
>  		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
>  		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>  
> @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
>  	struct meson_nfc *nfc = nand_get_controller_data(nand);
>  
>  	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
> -	if (infolen)
> +	if (infolen) {
>  		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
> +		nfc->info_bytes = 0;
> +	}
>  }
>  
>  static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
> @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
>  		usleep_range(10, 15);
>  		/* info is updated by nfc dma engine*/
>  		smp_rmb();
> +		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
> +					DMA_FROM_DEVICE);
>  		ret = *info & ECC_COMPLETE;
>  	} while (!ret);
>  }
Miquel Raynal March 13, 2023, 11:18 a.m. UTC | #2
Hi Arseniy,

avkrasnov@sberdevices.ru wrote on Mon, 13 Mar 2023 10:36:11 +0300:

> Hello,
> 
> we reproduced this problem on one of our boards. It triggers very rare
> when 'usleep_range()' is present, but when sleeping is removed - it fires
> always. I suppose problem is with caching, as 'info_buf' memory is mapped by
> 'dma_map_single()'.

The fix looks really legitimate, indeed I get that the usleep_range()
might make it work most of the time but not always. Having this bit in
a DMA buf area is a bit strange. Well, the fix LGTM anyway.

> 
> Thanks, Arseniy
> 
> On 13.03.2023 10:32, Arseniy Krasnov wrote:
> > 'info_buf' memory is cached and driver polls ECC bit in it. This bit
> > is set by the NAND controller. If 'usleep_range()' returns before device
> > sets this bit, 'info_buf' will be cached and driver won't see update of
> > this bit and will loop forever.
> > 
> > Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> > Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> > ---
> >  drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> > index 5ee01231ac4c..2c05c08a0eaf 100644
> > --- a/drivers/mtd/nand/raw/meson_nand.c
> > +++ b/drivers/mtd/nand/raw/meson_nand.c
> > @@ -176,6 +176,7 @@ struct meson_nfc {
> >  
> >  	dma_addr_t daddr;
> >  	dma_addr_t iaddr;
> > +	u32 info_bytes;
> >  
> >  	unsigned long assigned_cs;
> >  };
> > @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
> >  					 nfc->daddr, datalen, dir);
> >  			return ret;
> >  		}
> > +		nfc->info_bytes = infolen;
> >  		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
> >  		writel(cmd, nfc->reg_base + NFC_REG_CMD);
> >  
> > @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
> >  	struct meson_nfc *nfc = nand_get_controller_data(nand);
> >  
> >  	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
> > -	if (infolen)
> > +	if (infolen) {
> >  		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
> > +		nfc->info_bytes = 0;
> > +	}
> >  }
> >  
> >  static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
> > @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
> >  		usleep_range(10, 15);
> >  		/* info is updated by nfc dma engine*/
> >  		smp_rmb();
> > +		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
> > +					DMA_FROM_DEVICE);
> >  		ret = *info & ECC_COMPLETE;
> >  	} while (!ret);
> >  }  


Thanks,
Miquèl
Neil Armstrong March 13, 2023, 11:23 a.m. UTC | #3
On 13/03/2023 12:18, Miquel Raynal wrote:
> Hi Arseniy,
> 
> avkrasnov@sberdevices.ru wrote on Mon, 13 Mar 2023 10:36:11 +0300:
> 
>> Hello,
>>
>> we reproduced this problem on one of our boards. It triggers very rare
>> when 'usleep_range()' is present, but when sleeping is removed - it fires
>> always. I suppose problem is with caching, as 'info_buf' memory is mapped by
>> 'dma_map_single()'.
> 
> The fix looks really legitimate, indeed I get that the usleep_range()
> might make it work most of the time but not always. Having this bit in
> a DMA buf area is a bit strange. Well, the fix LGTM anyway.

Yep it looks legitimate!

LGTM


Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

> 
>>
>> Thanks, Arseniy
>>
>> On 13.03.2023 10:32, Arseniy Krasnov wrote:
>>> 'info_buf' memory is cached and driver polls ECC bit in it. This bit
>>> is set by the NAND controller. If 'usleep_range()' returns before device
>>> sets this bit, 'info_buf' will be cached and driver won't see update of
>>> this bit and will loop forever.
>>>
>>> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>> ---
>>>   drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
>>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>>> index 5ee01231ac4c..2c05c08a0eaf 100644
>>> --- a/drivers/mtd/nand/raw/meson_nand.c
>>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>>> @@ -176,6 +176,7 @@ struct meson_nfc {
>>>   
>>>   	dma_addr_t daddr;
>>>   	dma_addr_t iaddr;
>>> +	u32 info_bytes;
>>>   
>>>   	unsigned long assigned_cs;
>>>   };
>>> @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
>>>   					 nfc->daddr, datalen, dir);
>>>   			return ret;
>>>   		}
>>> +		nfc->info_bytes = infolen;
>>>   		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
>>>   		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>>   
>>> @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
>>>   	struct meson_nfc *nfc = nand_get_controller_data(nand);
>>>   
>>>   	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
>>> -	if (infolen)
>>> +	if (infolen) {
>>>   		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
>>> +		nfc->info_bytes = 0;
>>> +	}
>>>   }
>>>   
>>>   static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
>>> @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
>>>   		usleep_range(10, 15);
>>>   		/* info is updated by nfc dma engine*/
>>>   		smp_rmb();
>>> +		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
>>> +					DMA_FROM_DEVICE);
>>>   		ret = *info & ECC_COMPLETE;
>>>   	} while (!ret);
>>>   }
> 
> 
> Thanks,
> Miquèl
Dmitry Rokosov March 20, 2023, 10:43 a.m. UTC | #4
Hello guys!

Was it applied to some nand 'prepare-for-merge' release branch?

On Mon, Mar 13, 2023 at 12:23:12PM +0100, Neil Armstrong wrote:
> On 13/03/2023 12:18, Miquel Raynal wrote:
> > Hi Arseniy,
> > 
> > avkrasnov@sberdevices.ru wrote on Mon, 13 Mar 2023 10:36:11 +0300:
> > 
> > > Hello,
> > > 
> > > we reproduced this problem on one of our boards. It triggers very rare
> > > when 'usleep_range()' is present, but when sleeping is removed - it fires
> > > always. I suppose problem is with caching, as 'info_buf' memory is mapped by
> > > 'dma_map_single()'.
> > 
> > The fix looks really legitimate, indeed I get that the usleep_range()
> > might make it work most of the time but not always. Having this bit in
> > a DMA buf area is a bit strange. Well, the fix LGTM anyway.
> 
> Yep it looks legitimate!
> 
> LGTM
> 
> 
> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
> 
> > 
> > > 
> > > Thanks, Arseniy
> > > 
> > > On 13.03.2023 10:32, Arseniy Krasnov wrote:
> > > > 'info_buf' memory is cached and driver polls ECC bit in it. This bit
> > > > is set by the NAND controller. If 'usleep_range()' returns before device
> > > > sets this bit, 'info_buf' will be cached and driver won't see update of
> > > > this bit and will loop forever.
> > > > 
> > > > Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> > > > Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> > > > ---
> > > >   drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
> > > >   1 file changed, 7 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> > > > index 5ee01231ac4c..2c05c08a0eaf 100644
> > > > --- a/drivers/mtd/nand/raw/meson_nand.c
> > > > +++ b/drivers/mtd/nand/raw/meson_nand.c
> > > > @@ -176,6 +176,7 @@ struct meson_nfc {
> > > >   	dma_addr_t daddr;
> > > >   	dma_addr_t iaddr;
> > > > +	u32 info_bytes;
> > > >   	unsigned long assigned_cs;
> > > >   };
> > > > @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
> > > >   					 nfc->daddr, datalen, dir);
> > > >   			return ret;
> > > >   		}
> > > > +		nfc->info_bytes = infolen;
> > > >   		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
> > > >   		writel(cmd, nfc->reg_base + NFC_REG_CMD);
> > > > @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
> > > >   	struct meson_nfc *nfc = nand_get_controller_data(nand);
> > > >   	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
> > > > -	if (infolen)
> > > > +	if (infolen) {
> > > >   		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
> > > > +		nfc->info_bytes = 0;
> > > > +	}
> > > >   }
> > > >   static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
> > > > @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
> > > >   		usleep_range(10, 15);
> > > >   		/* info is updated by nfc dma engine*/
> > > >   		smp_rmb();
> > > > +		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
> > > > +					DMA_FROM_DEVICE);
> > > >   		ret = *info & ECC_COMPLETE;
> > > >   	} while (!ret);
> > > >   }
> > 
> > 
> > Thanks,
> > Miquèl
>
Miquel Raynal March 20, 2023, 10:55 a.m. UTC | #5
Hi Dmitry,

ddrokosov@sberdevices.ru wrote on Mon, 20 Mar 2023 13:43:14 +0300:

> Hello guys!
> 
> Was it applied to some nand 'prepare-for-merge' release branch?

Not yet, I'll apply it this week in mtd/fixes, you'll be noticed.

Thanks,
Miquèl

> On Mon, Mar 13, 2023 at 12:23:12PM +0100, Neil Armstrong wrote:
> > On 13/03/2023 12:18, Miquel Raynal wrote:  
> > > Hi Arseniy,
> > > 
> > > avkrasnov@sberdevices.ru wrote on Mon, 13 Mar 2023 10:36:11 +0300:
> > >   
> > > > Hello,
> > > > 
> > > > we reproduced this problem on one of our boards. It triggers very rare
> > > > when 'usleep_range()' is present, but when sleeping is removed - it fires
> > > > always. I suppose problem is with caching, as 'info_buf' memory is mapped by
> > > > 'dma_map_single()'.  
> > > 
> > > The fix looks really legitimate, indeed I get that the usleep_range()
> > > might make it work most of the time but not always. Having this bit in
> > > a DMA buf area is a bit strange. Well, the fix LGTM anyway.  
> > 
> > Yep it looks legitimate!
> > 
> > LGTM
> > 
> > 
> > Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
> >   
> > >   
> > > > 
> > > > Thanks, Arseniy
> > > > 
> > > > On 13.03.2023 10:32, Arseniy Krasnov wrote:  
> > > > > 'info_buf' memory is cached and driver polls ECC bit in it. This bit
> > > > > is set by the NAND controller. If 'usleep_range()' returns before device
> > > > > sets this bit, 'info_buf' will be cached and driver won't see update of
> > > > > this bit and will loop forever.
> > > > > 
> > > > > Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> > > > > Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> > > > > ---
> > > > >   drivers/mtd/nand/raw/meson_nand.c | 8 +++++++-
> > > > >   1 file changed, 7 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> > > > > index 5ee01231ac4c..2c05c08a0eaf 100644
> > > > > --- a/drivers/mtd/nand/raw/meson_nand.c
> > > > > +++ b/drivers/mtd/nand/raw/meson_nand.c
> > > > > @@ -176,6 +176,7 @@ struct meson_nfc {
> > > > >   	dma_addr_t daddr;
> > > > >   	dma_addr_t iaddr;
> > > > > +	u32 info_bytes;
> > > > >   	unsigned long assigned_cs;
> > > > >   };
> > > > > @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
> > > > >   					 nfc->daddr, datalen, dir);
> > > > >   			return ret;
> > > > >   		}
> > > > > +		nfc->info_bytes = infolen;
> > > > >   		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
> > > > >   		writel(cmd, nfc->reg_base + NFC_REG_CMD);
> > > > > @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
> > > > >   	struct meson_nfc *nfc = nand_get_controller_data(nand);
> > > > >   	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
> > > > > -	if (infolen)
> > > > > +	if (infolen) {
> > > > >   		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
> > > > > +		nfc->info_bytes = 0;
> > > > > +	}
> > > > >   }
> > > > >   static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
> > > > > @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
> > > > >   		usleep_range(10, 15);
> > > > >   		/* info is updated by nfc dma engine*/
> > > > >   		smp_rmb();
> > > > > +		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
> > > > > +					DMA_FROM_DEVICE);
> > > > >   		ret = *info & ECC_COMPLETE;
> > > > >   	} while (!ret);
> > > > >   }  
> > > 
> > > 
> > > Thanks,
> > > Miquèl  
> >   
>
Dmitry Rokosov March 20, 2023, 11:30 a.m. UTC | #6
Hello Miquèl,

On Mon, Mar 20, 2023 at 11:55:58AM +0100, Miquel Raynal wrote:
> Hi Dmitry,
> 
> ddrokosov@sberdevices.ru wrote on Mon, 20 Mar 2023 13:43:14 +0300:
> 
> > Hello guys!
> > 
> > Was it applied to some nand 'prepare-for-merge' release branch?
> 
> Not yet, I'll apply it this week in mtd/fixes, you'll be noticed.
> 
> Thanks,
> Miquèl
> 

Thank you for clarification!

[...]
Miquel Raynal March 22, 2023, 4:07 p.m. UTC | #7
On Mon, 2023-03-13 at 07:32:44 UTC, Arseniy Krasnov wrote:
> 'info_buf' memory is cached and driver polls ECC bit in it. This bit
> is set by the NAND controller. If 'usleep_range()' returns before device
> sets this bit, 'info_buf' will be cached and driver won't see update of
> this bit and will loop forever.
> 
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes, thanks.

Miquel
diff mbox series

Patch

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 5ee01231ac4c..2c05c08a0eaf 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -176,6 +176,7 @@  struct meson_nfc {
 
 	dma_addr_t daddr;
 	dma_addr_t iaddr;
+	u32 info_bytes;
 
 	unsigned long assigned_cs;
 };
@@ -503,6 +504,7 @@  static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
 					 nfc->daddr, datalen, dir);
 			return ret;
 		}
+		nfc->info_bytes = infolen;
 		cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
 		writel(cmd, nfc->reg_base + NFC_REG_CMD);
 
@@ -520,8 +522,10 @@  static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
 	struct meson_nfc *nfc = nand_get_controller_data(nand);
 
 	dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
-	if (infolen)
+	if (infolen) {
 		dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
+		nfc->info_bytes = 0;
+	}
 }
 
 static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
@@ -710,6 +714,8 @@  static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
 		usleep_range(10, 15);
 		/* info is updated by nfc dma engine*/
 		smp_rmb();
+		dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
+					DMA_FROM_DEVICE);
 		ret = *info & ECC_COMPLETE;
 	} while (!ret);
 }