Patchwork hw/m25p80.c: add WRSR(0x01) support

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Submitter Dante
Date Jan. 18, 2013, 6:17 a.m.
Message ID <1358489831-18005-1-git-send-email-dantesu@faraday-tech.com>
Download mbox | patch
Permalink /patch/213475/
State New
Headers show

Comments

Dante - Jan. 18, 2013, 6:17 a.m.
Atmel, SST and Intel/Numonyx serial flash tend to power up
with the software protection bits set.
And thus the new m25p80.c in linux kernel would always tries
to use WREN(0x06) + WRSR(0x01) to turn-off the protection.
The WEL(0x02) of status register is supposed to be cleared
after WRSR(0x01).
There are some drivers (i.e my own tiny driver for RTOSes) would
check the WEL(0x02) in status register to make sure the protection
is correctly turned off, so this patch is mandatory to me.

Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
---
 hw/m25p80.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)
Peter Crosthwaite - Jan. 26, 2013, 1:25 a.m.
Hi Dante,

Sorry about the delay, and thanks for the contribution. Please run the
patch through the provided checkpatch script (scripts/checkpatch.pl).
There are a few whitespace errors that need to be fixed. Please also
see the comment below.

Regards,
Peter

On Thu, Jan 17, 2013 at 10:17 PM, Dante <dantesu@faraday-tech.com> wrote:
> Atmel, SST and Intel/Numonyx serial flash tend to power up
> with the software protection bits set.
> And thus the new m25p80.c in linux kernel would always tries
> to use WREN(0x06) + WRSR(0x01) to turn-off the protection.
> The WEL(0x02) of status register is supposed to be cleared
> after WRSR(0x01).
> There are some drivers (i.e my own tiny driver for RTOSes) would
> check the WEL(0x02) in status register to make sure the protection
> is correctly turned off, so this patch is mandatory to me.
>
> Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
> ---
>  hw/m25p80.c |   16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/hw/m25p80.c b/hw/m25p80.c
> index d392656..c8d0411 100644
> --- a/hw/m25p80.c
> +++ b/hw/m25p80.c
> @@ -184,6 +184,7 @@ static const FlashPartInfo known_devices[] = {
>
>  typedef enum {
>      NOP = 0,
> +    WRSR = 0x1,
>      WRDI = 0x4,
>      RDSR = 0x5,
>      WREN = 0x6,
> @@ -377,6 +378,12 @@ static void complete_collecting_data(Flash *s)
>      case ERASE_SECTOR:
>          flash_erase(s, s->cur_addr, s->cmd_in_progress);
>          break;
> +    case WRSR:
> +       if (s->write_enable) {
> +               s->state = STATE_IDLE;

Returning to the idle state should be unconditional, if
(!s->write_enable), then if you issue a WRSR, you will get stuck in
COLLECTING_DATA.

Regards,
Peter

> +               s->write_enable = false;
> +       }
> +       break;
>      default:
>          break;
>      }
> @@ -440,6 +447,15 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>          s->len = 0;
>          s->state = STATE_COLLECTING_DATA;
>          break;
> +
> +       case WRSR:
> +               if (s->write_enable) {
> +                       s->needed_bytes = 1;
> +                       s->pos = 0;
> +               s->len = 0;
> +                       s->state = STATE_COLLECTING_DATA;
> +               }
> +        break;
>
>      case WRDI:
>          s->write_enable = false;
> --
> 1.7.9.5
>
>
> ********************* Confidentiality Notice ************************
> This electronic message and any attachments may contain
> confidential and legally privileged information or
> information which is otherwise protected from disclosure.
> If you are not the intended recipient,please do not disclose
> the contents, either in whole or in part, to anyone,and
> immediately delete the message and any attachments from
> your computer system and destroy all hard copies.
> Thank you for your cooperation.
> ***********************************************************************
>
Peter Crosthwaite - Jan. 26, 2013, 1:34 a.m.
Hi Dante,

On Fri, Jan 25, 2013 at 5:25 PM, Peter Crosthwaite
<peter.crosthwaite@xilinx.com> wrote:
> Hi Dante,
>
> Sorry about the delay, and thanks for the contribution. Please run the
> patch through the provided checkpatch script (scripts/checkpatch.pl).
> There are a few whitespace errors that need to be fixed. Please also
> see the comment below.
>
> Regards,
> Peter
>
> On Thu, Jan 17, 2013 at 10:17 PM, Dante <dantesu@faraday-tech.com> wrote:
>> Atmel, SST and Intel/Numonyx serial flash tend to power up
>> with the software protection bits set.
>> And thus the new m25p80.c in linux kernel would always tries
>> to use WREN(0x06) + WRSR(0x01) to turn-off the protection.
>> The WEL(0x02) of status register is supposed to be cleared
>> after WRSR(0x01).
>> There are some drivers (i.e my own tiny driver for RTOSes) would
>> check the WEL(0x02) in status register to make sure the protection
>> is correctly turned off, so this patch is mandatory to me.
>>
>> Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
>> ---
>>  hw/m25p80.c |   16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>>
>> diff --git a/hw/m25p80.c b/hw/m25p80.c
>> index d392656..c8d0411 100644
>> --- a/hw/m25p80.c
>> +++ b/hw/m25p80.c
>> @@ -184,6 +184,7 @@ static const FlashPartInfo known_devices[] = {
>>
>>  typedef enum {
>>      NOP = 0,
>> +    WRSR = 0x1,
>>      WRDI = 0x4,
>>      RDSR = 0x5,
>>      WREN = 0x6,
>> @@ -377,6 +378,12 @@ static void complete_collecting_data(Flash *s)
>>      case ERASE_SECTOR:
>>          flash_erase(s, s->cur_addr, s->cmd_in_progress);
>>          break;
>> +    case WRSR:
>> +       if (s->write_enable) {
>> +               s->state = STATE_IDLE;
>
> Returning to the idle state should be unconditional, if
> (!s->write_enable), then if you issue a WRSR, you will get stuck in
> COLLECTING_DATA.
>

Reviewing this a little more, transitioning back to IDLE is handled by
the de-assertion of the chip-select. So you should by able to just
remove this s->state = STATE_IDLE altogether.

Regards,
Peter

> Regards,
> Peter
>
>> +               s->write_enable = false;
>> +       }
>> +       break;
>>      default:
>>          break;
>>      }
>> @@ -440,6 +447,15 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>>          s->len = 0;
>>          s->state = STATE_COLLECTING_DATA;
>>          break;
>> +
>> +       case WRSR:
>> +               if (s->write_enable) {
>> +                       s->needed_bytes = 1;
>> +                       s->pos = 0;
>> +               s->len = 0;
>> +                       s->state = STATE_COLLECTING_DATA;
>> +               }
>> +        break;
>>
>>      case WRDI:
>>          s->write_enable = false;
>> --
>> 1.7.9.5
>>
>>
>> ********************* Confidentiality Notice ************************
>> This electronic message and any attachments may contain
>> confidential and legally privileged information or
>> information which is otherwise protected from disclosure.
>> If you are not the intended recipient,please do not disclose
>> the contents, either in whole or in part, to anyone,and
>> immediately delete the message and any attachments from
>> your computer system and destroy all hard copies.
>> Thank you for your cooperation.
>> ***********************************************************************
>>
Kuo-Jung Su - Jan. 28, 2013, 7:10 a.m.
2013/1/26 Peter Crosthwaite <peter.crosthwaite@xilinx.com>

> Hi Dante,
>
> On Fri, Jan 25, 2013 at 5:25 PM, Peter Crosthwaite
> <peter.crosthwaite@xilinx.com> wrote:
> > Hi Dante,
> >
> > Sorry about the delay, and thanks for the contribution. Please run the
> > patch through the provided checkpatch script (scripts/checkpatch.pl).
> > There are a few whitespace errors that need to be fixed. Please also
> > see the comment below.
> >
> > Regards,
> > Peter
> >
> > On Thu, Jan 17, 2013 at 10:17 PM, Dante <dantesu@faraday-tech.com>
> wrote:
> >> Atmel, SST and Intel/Numonyx serial flash tend to power up
> >> with the software protection bits set.
> >> And thus the new m25p80.c in linux kernel would always tries
> >> to use WREN(0x06) + WRSR(0x01) to turn-off the protection.
> >> The WEL(0x02) of status register is supposed to be cleared
> >> after WRSR(0x01).
> >> There are some drivers (i.e my own tiny driver for RTOSes) would
> >> check the WEL(0x02) in status register to make sure the protection
> >> is correctly turned off, so this patch is mandatory to me.
> >>
> >> Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
> >> ---
> >>  hw/m25p80.c |   16 ++++++++++++++++
> >>  1 file changed, 16 insertions(+)
> >>
> >> diff --git a/hw/m25p80.c b/hw/m25p80.c
> >> index d392656..c8d0411 100644
> >> --- a/hw/m25p80.c
> >> +++ b/hw/m25p80.c
> >> @@ -184,6 +184,7 @@ static const FlashPartInfo known_devices[] = {
> >>
> >>  typedef enum {
> >>      NOP = 0,
> >> +    WRSR = 0x1,
> >>      WRDI = 0x4,
> >>      RDSR = 0x5,
> >>      WREN = 0x6,
> >> @@ -377,6 +378,12 @@ static void complete_collecting_data(Flash *s)
> >>      case ERASE_SECTOR:
> >>          flash_erase(s, s->cur_addr, s->cmd_in_progress);
> >>          break;
> >> +    case WRSR:
> >> +       if (s->write_enable) {
> >> +               s->state = STATE_IDLE;
> >
> > Returning to the idle state should be unconditional, if
> > (!s->write_enable), then if you issue a WRSR, you will get stuck in
> > COLLECTING_DATA.
> >
>
> Reviewing this a little more, transitioning back to IDLE is handled by
> the de-assertion of the chip-select. So you should by able to just
> remove this s->state = STATE_IDLE altogether.
>
> Regards,
> Peter
>

Thanks for the comment, I'll send out a new patch with correct coding style
later

Best Wishes
Dante

>
> > Regards,
> > Peter
> >
> >> +               s->write_enable = false;
> >> +       }
> >> +       break;
> >>      default:
> >>          break;
> >>      }
> >> @@ -440,6 +447,15 @@ static void decode_new_cmd(Flash *s, uint32_t
> value)
> >>          s->len = 0;
> >>          s->state = STATE_COLLECTING_DATA;
> >>          break;
> >> +
> >> +       case WRSR:
> >> +               if (s->write_enable) {
> >> +                       s->needed_bytes = 1;
> >> +                       s->pos = 0;
> >> +               s->len = 0;
> >> +                       s->state = STATE_COLLECTING_DATA;
> >> +               }
> >> +        break;
> >>
> >>      case WRDI:
> >>          s->write_enable = false;
> >> --
> >> 1.7.9.5
> >>
> >>
> >> ********************* Confidentiality Notice ************************
> >> This electronic message and any attachments may contain
> >> confidential and legally privileged information or
> >> information which is otherwise protected from disclosure.
> >> If you are not the intended recipient,please do not disclose
> >> the contents, either in whole or in part, to anyone,and
> >> immediately delete the message and any attachments from
> >> your computer system and destroy all hard copies.
> >> Thank you for your cooperation.
> >> ***********************************************************************
> >>
>
>

Patch

diff --git a/hw/m25p80.c b/hw/m25p80.c
index d392656..c8d0411 100644
--- a/hw/m25p80.c
+++ b/hw/m25p80.c
@@ -184,6 +184,7 @@  static const FlashPartInfo known_devices[] = {
 
 typedef enum {
     NOP = 0,
+    WRSR = 0x1,
     WRDI = 0x4,
     RDSR = 0x5,
     WREN = 0x6,
@@ -377,6 +378,12 @@  static void complete_collecting_data(Flash *s)
     case ERASE_SECTOR:
         flash_erase(s, s->cur_addr, s->cmd_in_progress);
         break;
+    case WRSR:
+    	if (s->write_enable) {
+    		s->state = STATE_IDLE;
+    		s->write_enable = false;
+    	}
+    	break;
     default:
         break;
     }
@@ -440,6 +447,15 @@  static void decode_new_cmd(Flash *s, uint32_t value)
         s->len = 0;
         s->state = STATE_COLLECTING_DATA;
         break;
+        
+	case WRSR:
+		if (s->write_enable) {
+			s->needed_bytes = 1;
+			s->pos = 0;
+        	s->len = 0;
+			s->state = STATE_COLLECTING_DATA;
+		}
+        break;
 
     case WRDI:
         s->write_enable = false;