Re: [Qemu-devel] [PATCH v2 04/14] sdcard: Extract sd_frame48/136_calc_checksum()

[Philippe Mathieu-Daudé]

Hi Alistair,

On 05/09/2018 03:00 PM, Alistair Francis wrote:
> On Tue, May 8, 2018 at 8:46 PM, Philippe Mathieu-Daudé <address@hidden> wrote:
>> It will help when moving this around for qtesting in the next commit.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
>> ---
>>  hw/sd/sd.c | 21 ++++++++++++++++++---
>>  1 file changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
>> index 27a70896cd..06607115a7 100644
>> --- a/hw/sd/sd.c
>> +++ b/hw/sd/sd.c
>> @@ -273,6 +273,21 @@ static uint16_t sd_crc16(const void *message, size_t 
>> width)
>>      return shift_reg;
>>  }
>>
>> +enum {
>> +    F48_CONTENT_LENGTH  = 1 /* command */ + 4 /* argument */,
>> +    F136_CONTENT_LENGTH = 15,
>> +};
>> +
>> +static uint8_t sd_frame48_calc_checksum(const void *content)
>> +{
>> +    return sd_crc7(content, F48_CONTENT_LENGTH);
>> +}
>> +
>> +static uint8_t sd_frame136_calc_checksum(const void *content)
>> +{
>> +    return (sd_crc7(content, F136_CONTENT_LENGTH) << 1) | 1;
>> +}
>> +
>>  #define OCR_POWER_DELAY_NS      500000 /* 0.5ms */
>>
>>  FIELD(OCR, VDD_VOLTAGE_WINDOW,          0, 24)
>> @@ -352,7 +367,7 @@ static void sd_set_cid(SDState *sd)
>>      sd->cid[13] = 0x00 |       /* Manufacture date (MDT) */
>>          ((MDT_YR - 2000) / 10);
>>      sd->cid[14] = ((MDT_YR % 10) << 4) | MDT_MON;
>> -    sd->cid[15] = (sd_crc7(sd->cid, 15) << 1) | 1;
>> +    sd->cid[15] = sd_frame136_calc_checksum(sd->cid);
>>  }
>>
>>  #define HWBLOCK_SHIFT  9                       /* 512 bytes */
>> @@ -416,7 +431,7 @@ static void sd_set_csd(SDState *sd, uint64_t size)
>>          sd->csd[13] = 0x40;
>>          sd->csd[14] = 0x00;
>>      }
>> -    sd->csd[15] = (sd_crc7(sd->csd, 15) << 1) | 1;
>> +    sd->csd[15] = sd_frame136_calc_checksum(sd->csd);
>>  }
>>
>>  static void sd_set_rca(SDState *sd)
>> @@ -491,7 +506,7 @@ static int sd_req_crc_validate(SDRequest *req)
>>      buffer[0] = 0x40 | req->cmd;
>>      stl_be_p(&buffer[1], req->arg);
>>      return 0;
>> -    return sd_crc7(buffer, 5) != req->crc;     /* TODO */
>> +    return sd_frame48_calc_checksum(buffer) != req->crc; /* TODO */
> 
> This 5 has changed to a 15. Is that on purpose? It should be mentioned
> in the commit message if it is.

I just extracted this function:

  static uint8_t sd_frame48_calc_checksum(const void *content)
  {
      return sd_crc7(content, F48_CONTENT_LENGTH);
  }

Having:

  enum {
      F48_CONTENT_LENGTH  = 1 /* command */ + 4 /* argument */,

So F48_CONTENT_LENGTH = 5 as previous.

This function is later verified with tests from patch 12 of this series.

> 
> Alistair
> 
>>  }
>>
>>  static void sd_response_r1_make(SDState *sd, uint8_t *response)
>> --
>> 2.17.0
>>
>>