Hi Dante,
On Fri, Jan 25, 2013 at 5:25 PM, Peter Crosthwaite
<peter.crosthwa...@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 <dant...@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 <dant...@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
>>
>>
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