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Re: [Qemu-devel] [PATCH v4 05/11] block: m25p80: 4byte address mode


From: Krzeminski, Marcin (Nokia - PL/Wroclaw)
Subject: Re: [Qemu-devel] [PATCH v4 05/11] block: m25p80: 4byte address mode
Date: Fri, 18 Mar 2016 13:00:03 +0000


> -----Original Message-----
> From: EXT Peter Crosthwaite [mailto:address@hidden
> Sent: Thursday, March 17, 2016 6:27 PM
> To: Krzeminski, Marcin (Nokia - PL/Wroclaw)
> <address@hidden>
> Cc: address@hidden Developers <address@hidden>;
> C├ędric Le Goater <address@hidden>; address@hidden
> Subject: Re: [PATCH v4 05/11] block: m25p80: 4byte address mode
> 
> On Mon, Feb 22, 2016 at 12:03 AM,  <address@hidden> wrote:
> > From: Marcin Krzeminski <address@hidden>
> >
> > This patch adds only 4byte address mode (does not cover dummy cycles).
> > This mode is needed to access more than 16 MiB of flash.
> >
> > Signed-off-by: Marcin Krzeminski <address@hidden>
> > ---
> >  hw/block/m25p80.c | 41 +++++++++++++++++++++++++++++++++++-----
> -
> >  1 file changed, 35 insertions(+), 6 deletions(-)
> >
> > diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c index
> > 0540dde..0698e7b 100644
> > --- a/hw/block/m25p80.c
> > +++ b/hw/block/m25p80.c
> > @@ -237,6 +237,9 @@ typedef enum {
> >      ERASE_32K = 0x52,
> >      ERASE_SECTOR = 0xd8,
> >
> > +    EN_4BYTE_ADDR = 0xB7,
> > +    EX_4BYTE_ADDR = 0xE9,
> > +
> >      EXTEND_ADDR_READ = 0xC8,
> >      EXTEND_ADDR_WRITE = 0xC5,
> >
> > @@ -269,6 +272,7 @@ typedef struct Flash {
> >      uint8_t cmd_in_progress;
> >      uint64_t cur_addr;
> >      bool write_enable;
> > +    bool four_bytes_address_mode;
> >      bool reset_enable;
> >      uint8_t ear;
> >
> > @@ -406,12 +410,25 @@ void flash_write8(Flash *s, uint64_t addr, uint8_t
> data)
> >      s->dirty_page = page;
> >  }
> >
> > +static inline int get_addr_length(Flash *s) {
> > +    return s->four_bytes_address_mode ? 4 : 3; }
> > +
> >  static void complete_collecting_data(Flash *s)  {
> > -    s->cur_addr = s->data[0] << 16;
> > -    s->cur_addr |= s->data[1] << 8;
> > -    s->cur_addr |= s->data[2];
> > -    s->cur_addr += (s->ear & 0x3) * MAX_3BYTES_SIZE;
> > +    int i;
> > +
> > +    s->cur_addr = 0;
> > +
> > +    for (i = 0; i < get_addr_length(s); ++i) {
> > +        s->cur_addr <<= 8;
> > +        s->cur_addr |= s->data[i];
> > +    }
> > +
> > +    if (get_addr_length(s) == 3) {
> > +        s->cur_addr += (s->ear & 0x3) * MAX_3BYTES_SIZE;
> > +    }
> >
> >      s->state = STATE_IDLE;
> >
> > @@ -452,6 +469,7 @@ static void reset_memory(Flash *s)
> >      s->cmd_in_progress = NOP;
> >      s->cur_addr = 0;
> >      s->ear = 0;
> > +    s->four_bytes_address_mode = false;
> >      s->len = 0;
> >      s->needed_bytes = 0;
> >      s->pos = 0;
> > @@ -480,7 +498,7 @@ static void decode_new_cmd(Flash *s, uint32_t
> value)
> >      case DPP:
> >      case QPP:
> >      case PP:
> > -        s->needed_bytes = 3;
> > +        s->needed_bytes = get_addr_length(s);
> >          s->pos = 0;
> >          s->len = 0;
> >          s->state = STATE_COLLECTING_DATA; @@ -489,7 +507,7 @@ static
> > void decode_new_cmd(Flash *s, uint32_t value)
> >      case FAST_READ:
> >      case DOR:
> >      case QOR:
> > -        s->needed_bytes = 4;
> > +        s->needed_bytes = get_addr_length(s);
> 
> You fix this later with the configuration of dummy cycles, but you should
> preserve the existing behaviour until your fix lands. This means that you
> should have +1 here.
True, all is that because there is a 11 patches for one file. From logical 
point of view
this make sense, but from device emulation point of view applying not whole
series it does not.
> 
> >          s->pos = 0;
> >          s->len = 0;
> >          s->state = STATE_COLLECTING_DATA; @@ -502,6 +520,8 @@ static
> > void decode_new_cmd(Flash *s, uint32_t value)
> >              s->needed_bytes = 4;
> >              break;
> >          case JEDEC_NUMONYX:
> > +            s->needed_bytes = get_addr_length(s);
> > +            break;
> 
> This change ...
> 
> >          default:
> >              s->needed_bytes = 5;
> 
> Should be here, with a +2 (I think?).
Yes, but I would not prefer this in default, but since there is not much time 
and it
does not change functionality I will put all in default, but change it with 
Macronix
and Spansion future patch series (for those I reworked a bit all that switches 
so it is
already changed there).

Thanks,
Marcin
> 
> >          }
> > @@ -517,6 +537,8 @@ static void decode_new_cmd(Flash *s, uint32_t
> value)
> >              s->needed_bytes = 6;
> >              break;
> >          case JEDEC_NUMONYX:
> > +            s->needed_bytes = get_addr_length(s);
> > +            break;
> 
> Similar.
> 
> Otherwise,
> 
> Reviewed-by: Peter Crosthwaite <address@hidden>
> 
> Regards,
> Peter
> 
> >          default:
> >              s->needed_bytes = 8;
> >          }
> > @@ -575,6 +597,12 @@ static void decode_new_cmd(Flash *s, uint32_t
> value)
> >          break;
> >      case NOP:
> >          break;
> > +    case EN_4BYTE_ADDR:
> > +        s->four_bytes_address_mode = true;
> > +        break;
> > +    case EX_4BYTE_ADDR:
> > +        s->four_bytes_address_mode = false;
> > +        break;
> >      case EXTEND_ADDR_READ:
> >          s->data[0] = s->ear;
> >          s->pos = 0;
> > @@ -724,6 +752,7 @@ static const VMStateDescription vmstate_m25p80 =
> {
> >          VMSTATE_UINT8(cmd_in_progress, Flash),
> >          VMSTATE_UINT64(cur_addr, Flash),
> >          VMSTATE_BOOL(write_enable, Flash),
> > +        VMSTATE_BOOL(four_bytes_address_mode, Flash),
> >          VMSTATE_UINT8(ear, Flash),
> >          VMSTATE_BOOL(reset_enable, Flash),
> >          VMSTATE_END_OF_LIST()
> > --
> > 2.5.0
> >

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