Re: [Qemu-devel] [PATCH v2 05/11] block: m25p80: 4byte address mode

["Cédric Le Goater" <clg@fr.ibm.com>]

Hello Marcin,

Some comments below


On 02/04/2016 01:23 PM, marcin.krzeminski@nokia.com wrote:
> From: Marcin Krzeminski <marcin.krzeminski@nokia.com>
> 
> 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 <marcin.krzeminski@nokia.com>
> ---
>  hw/block/m25p80.c | 40 +++++++++++++++++++++++++++++++++++-----
>  1 file changed, 35 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
> index 6b5f00d..e306356 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 +410,26 @@ void flash_write8(Flash *s, uint64_t addr, uint8_t data)
>      s->dirty_page = page;
>  }
> 
> +static inline int get_cmd_length(Flash *s)

The name is bit confusing, it is not really a command length 
but an address width ? 

> +{
> +       return s->four_bytes_address_mode ? 4 : 3;
> +   }

one '}' should be enough :)

> +}
> +
>  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];
> +    int i;
> +
> +    s->cur_addr = 0;
> +
> +    for ( i=0; i< get_cmd_length(s); ++i ) {

white space issues above 

> +        s->cur_addr <<= 8;
> +        s->cur_addr |= s->data[i];
> +    }
> +
> +    if ( get_cmd_length(s) == 3) {

white space issues above


C.


>          s->cur_addr += (s->ear & 0x3) * MAX_3BYTES_SIZE;
> +    }
> 
>      s->state = STATE_IDLE;
> 
> @@ -452,6 +470,7 @@ 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 +499,7 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>      case DPP:
>      case QPP:
>      case PP:
> -        s->needed_bytes = 3;
> +        s->needed_bytes = get_cmd_length(s);
>          s->pos = 0;
>          s->len = 0;
>          s->state = STATE_COLLECTING_DATA;
> @@ -489,7 +508,7 @@ 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_cmd_length(s);
>          s->pos = 0;
>          s->len = 0;
>          s->state = STATE_COLLECTING_DATA;
> @@ -502,6 +521,8 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>              s->needed_bytes = 4;
>              break;
>          case JEDEC_NUMONYX:
> +            s->needed_bytes = get_cmd_length(s);
> +            break;
>          default:
>              s->needed_bytes = 5;
>          }
> @@ -517,6 +538,8 @@ static void decode_new_cmd(Flash *s, uint32_t value)
>              s->needed_bytes = 6;
>              break;
>          case JEDEC_NUMONYX:
> +            s->needed_bytes = get_cmd_length(s);
> +            break;
>          default:
>              s->needed_bytes = 8;
>          }
> @@ -575,6 +598,12 @@ 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;
> @@ -725,6 +754,7 @@ 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()
>