Re: [PATCH] mtd: rawnand: qcom: update last code word register

[mdalam]

On 2021-02-18 14:50, Miquel Raynal wrote:

Hello,

>> >> +/* helper to configure location register values */
>> +static void nandc_set_read_loc(struct nand_chip *chip, int cw, int >> reg,
>> +                             int offset, int size, int is_last)
>
> You know cw, you have access to chip->ecc.steps, so you can derive by
> yourself if is_last is set or not. No need to forward it through
> function calls.

This "is_last" is not for last code word, it will indicate the Location register "NAND_READ_LOCATION_n" last bit.

Ok, I've mixed two things. Let's keep this boolean as it is for now and
just do the minimum changes to support the LOCATION_LAST_cw registers.

Nevertheless, can't you calculate is_last from nandc_set_read_loc() ?

I also think a bit of renaming (in a different patch) would be welcome
to avoid such confusions.

Just to be clear: I think you should take a step back, and try to
simplify a bit this driver. I understand you know every character by
heart but with an external eye it's not that easy to understand what
you want to do and why:
- write small commits with a single, atomic change
- try to reduce the number of parameters when it is possible
- try to use meaningful names (is_last vs. LAST_CW)
- try to avoid extra indentation level when possible

  Sure , I will try to split these changes in multiple patches
  and re-pushed again.

[...]

>> @@ -1094,11 +1144,19 @@ static void

config_nand_page_read(struct

qcom_nand_controller *nandc)

>>   * before reading each codeword in NAND page.
>>   */
>>  static void
>> -config_nand_cw_read(struct qcom_nand_controller *nandc, bool use_ecc)
>> +config_nand_cw_read(struct nand_chip *chip, bool use_ecc, int cw)
>>  {
>> -      if (nandc->props->is_bam)
>> -              write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
>> -                            NAND_BAM_NEXT_SGL);
>> +      struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
>> +      struct nand_ecc_ctrl *ecc = &chip->ecc;
>> +
>> +      if (nandc->props->is_bam) {
>> +              if (nandc->props->qpic_v2 && cw == (ecc->steps - 1))
>> +                      write_reg_dma(nandc, NAND_READ_LOCATION_LAST_CW_0, 4,
>> +                                    NAND_BAM_NEXT_SGL);
>> +              else
>> +                      write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
>> +                                    NAND_BAM_NEXT_SGL);
>> +      }
>
> Same here, I am pretty sure we can abstract the complexity.
>

Here I did this because , i need pointer to struct nand_ecc_ctrl structure to access ecc->steps for CW comparison for last code word. cw == (ecc->steps - 1)

    So i think no separate patch needed for conversion of nanc-->chip.

Please let me know if still separate patch needed for nanc-->chip conversion.

I was talking about the extra indentation level.

the "qpic_v2 && cv == ..." condition can be checked by write_reg_dma
directly.

You could even introduce a helper returning the boolean value of which
register should be used.

Regarding the use of nand_chip instead of nandc, if there are too many
changes involved, I prefer a separate patch.

  I will push separate patch for nandc to chip conversion.

>> >>       write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
>>        write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
>> @@ -1117,11 +1175,11 @@ config_nand_cw_read(struct >> qcom_nand_controller 
*nandc, bool use_ecc)
>>   * single codeword in page
>>   */
>>  static void
>> -config_nand_single_cw_page_read(struct qcom_nand_controller *nandc,
>> -                              bool use_ecc)
>> +config_nand_single_cw_page_read(struct nand_chip *chip,
>> +                              bool use_ecc, int cw)
>>  {
>> -      config_nand_page_read(nandc);
>> -      config_nand_cw_read(nandc, use_ecc);
>> +      config_nand_page_read(chip);
>> +      config_nand_cw_read(chip, use_ecc, cw);
>>  }
>> >>  /*
>> @@ -1205,7 +1263,7 @@ static int nandc_param(struct qcom_nand_host >> *host)
>>                nandc_set_reg(nandc, NAND_DEV_CMD_VLD_RESTORE, nandc->vld);
>>        }
>> >> -     nandc_set_read_loc(nandc, 0, 0, 512, 1);
>> +      nandc_set_read_loc(chip, 0, 0, 0, 512, 1);
>> >>       if (!nandc->props->qpic_v2) {
>>                write_reg_dma(nandc, NAND_DEV_CMD_VLD, 1, 0);
>> @@ -1215,7 +1273,7 @@ static int nandc_param(struct qcom_nand_host >> *host)
>>        nandc->buf_count = 512;
>>        memset(nandc->data_buffer, 0xff, nandc->buf_count);
>> >> -     config_nand_single_cw_page_read(nandc, false);
>> +      config_nand_single_cw_page_read(chip, false, 0);
>> >>       read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer,
>>                      nandc->buf_count, 0);
>> @@ -1617,7 +1675,7 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, >> struct 
nand_chip *chip,
>>        clear_bam_transaction(nandc);
>>        set_address(host, host->cw_size * cw, page);
>>        update_rw_regs(host, 1, true);
>> -      config_nand_page_read(nandc);
>> +      config_nand_page_read(chip);
>> >>       data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
>>        oob_size1 = host->bbm_size;
>> @@ -1633,19 +1691,19 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, >> 
struct nand_chip *chip,
>>        }
>> >>       if (nandc->props->is_bam) {
>> -              nandc_set_read_loc(nandc, 0, read_loc, data_size1, 0);
>> +              nandc_set_read_loc(chip, cw, 0, read_loc, data_size1, 0);
>>                read_loc += data_size1;
>> >> -             nandc_set_read_loc(nandc, 1, read_loc, oob_size1, 0);
>> +              nandc_set_read_loc(chip, cw, 1, read_loc, oob_size1, 0);
>>                read_loc += oob_size1;
>> >> -             nandc_set_read_loc(nandc, 2, read_loc, data_size2, 0);
>> +              nandc_set_read_loc(chip, cw, 2, read_loc, data_size2, 0);
>>                read_loc += data_size2;
>> >> -             nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
>> +              nandc_set_read_loc(chip, cw, 3, read_loc, oob_size2, 1);
>>        }
>> >> -     config_nand_cw_read(nandc, false);
>> +      config_nand_cw_read(chip, false, cw);
>> >>       read_data_dma(nandc, reg_off, data_buf, data_size1, 0);
>>        reg_off += data_size1;
>> @@ -1856,7 +1914,7 @@ static int read_page_ecc(struct qcom_nand_host >> 
*host, u8 *data_buf,
>>        u8 *data_buf_start = data_buf, *oob_buf_start = oob_buf;
>>        int i, ret;
>> >> -     config_nand_page_read(nandc);
>> +      config_nand_page_read(chip);
>> >>       /* queue cmd descs for each codeword */
>>        for (i = 0; i < ecc->steps; i++) {
>> @@ -1873,18 +1931,16 @@ static int read_page_ecc(struct qcom_nand_host >> 
*host, u8 *data_buf,
>> >>               if (nandc->props->is_bam) {
>>                        if (data_buf && oob_buf) {
>> -                              nandc_set_read_loc(nandc, 0, 0, data_size, 0);
>> -                              nandc_set_read_loc(nandc, 1, data_size,
>> -                                                 oob_size, 1);
>> +                              nandc_set_read_loc(chip, i, 0, 0, data_size, 
0);
>> +                              nandc_set_read_loc(chip, i, 1, data_size, 
oob_size, 1);
>>                        } else if (data_buf) {
>> -                              nandc_set_read_loc(nandc, 0, 0, data_size, 1);
>> +                              nandc_set_read_loc(chip, i, 0, 0, data_size, 
1);
>>                        } else {
>> -                              nandc_set_read_loc(nandc, 0, data_size,
>> -                                                 oob_size, 1);
>> +                              nandc_set_read_loc(chip, i, 0, data_size, 
oob_size, 1);
>>                        }
>>                }
>> >> -             config_nand_cw_read(nandc, true);
>> +              config_nand_cw_read(chip, true, i);
>> >>               if (data_buf)
>>                        read_data_dma(nandc, FLASH_BUF_ACC, data_buf,
>> @@ -1946,7 +2002,7 @@ static int copy_last_cw(struct qcom_nand_host >> 
*host, int page)
>>        set_address(host, host->cw_size * (ecc->steps - 1), page);
>>        update_rw_regs(host, 1, true);
>> >> -     config_nand_single_cw_page_read(nandc, host->use_ecc);
>> +      config_nand_single_cw_page_read(chip, host->use_ecc, ecc->steps - >> 
1);
>> >>       read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, size, 0);
>> > > Thanks,
> Miquèl

Thanks,
Miquèl