A previous patch implemented an incomplete workaround of erratum
A-008171. The complete workaround is as below. This patch is to
implement the complete workaround which uses SW tuning if HW tuning
fails, and retries both HW/SW tuning once with reduced clock if
workaround fails. This is suggested by hardware team, and the patch
had been verified on LS1046A eSDHC + Phison 32G eMMC which could
trigger the erratum.

Workaround:
/* For T1040, T2080, LS1021A, T1023 Rev 1: */
1. Program TBPTR[TB_WNDW_END_PTR] = 3*DIV_RATIO.
2. Program TBPTR[TB_WNDW_START_PTR] = 5*DIV_RATIO.
3. Program the software tuning mode by setting TBCTL[TB_MODE] = 2'h3.
4. Set SYSCTL2[EXTN] and SYSCTL2[SAMPCLKSEL].
5. Issue SEND_TUNING_BLK Command (CMD19 for SD, CMD21 for MMC).
6. Wait for IRQSTAT[BRR], buffer read ready, to be set.
7. Clear IRQSTAT[BRR].
8. Check SYSCTL2[EXTN] to be cleared.
9. Check SYSCTL2[SAMPCLKSEL], Sampling Clock Select. It's set value
   indicate tuning procedure success, and clear indicate failure.
   In case of tuning failure, fixed sampling scheme could be used by
   clearing TBCTL[TB_EN].
/* For LS1080A Rev 1, LS2088A Rev 1.0, LA1575A Rev 1.0: */
1. Read the TBCTL[31:0] register. Write TBCTL[11:8]=4'h8 and wait for
   1ms.
2. Read the TBCTL[31:0] register and rewrite again. Wait for 1ms second.
3. Read the TBSTAT[31:0] register twice.
3.1 Reset data lines by setting ESDHCCTL[RSTD] bit.
3.2 Check ESDHCCTL[RSTD] bit.
3.3 If ESDHCCTL[RSTD] is 0, go to step 3.4 else go to step 3.2.
3.4 Write 32'hFFFF_FFFF to IRQSTAT register.
4. if TBSTAT[15:8]-TBSTAT[7:0] > 4*DIV_RATIO or TBSTAT[7:0]-TBSTAT[15:8]
   > 4*DIV_RATIO , then program TBPTR[TB_WNDW_END_PTR] = 4*DIV_RATIO and
   program TBPTR[TB_WNDW_START_PTR] = 8*DIV_RATIO.
/* For LS1012A Rev1, LS1043A Rev 1.x, LS1046A 1.0: */
1. Read the TBCTL[0:31] register. Write TBCTL[20:23]=4'h8 and wait for
   1ms.
2. Read the TBCTL[0:31] register and rewrite again. Wait for 1ms second.
3. Read the TBSTAT[0:31] register twice.
3.1 Reset data lines by setting ESDHCCTL[RSTD] bit.
3.2 Check ESDHCCTL[RSTD] bit.
3.3 If ESDHCCTL[RSTD] is 0, go to step 3.4 else go to step 3.2.
3.4 Write 32'hFFFF_FFFF to IRQSTAT register.
4. if TBSTAT[16:23]-TBSTAT[24:31] > 4*DIV_RATIO or TBSTAT[24:31]-
   TBSTAT[16:23] > 4* DIV_RATIO , then program TBPTR[TB_WNDW_END_PTR] =
   4*DIV_RATIO and program TBPTR[TB_WNDW_START_PTR] = 8*DIV_RATIO.
/* For LS1080A Rev 1, LS2088A Rev 1.0, LA1575A Rev 1.0 LS1012A Rev1,
 * LS1043A Rev 1.x, LS1046A 1.0:
 */
5. else program TBPTR[TB_WNDW_END_PTR] = 3*DIV_RATIO and program
   TBPTR[TB_WNDW_START_PTR] = 5*DIV_RATIO.
6. Program the software tuning mode by setting TBCTL[TB_MODE] = 2'h3.
7. Set SYSCTL2[EXTN], wait 1us and SYSCTL2[SAMPCLKSEL].
8. Issue SEND_TUNING_BLK Command (CMD19 for SD, CMD21 for MMC).
9. Wait for IRQSTAT[BRR], buffer read ready, to be set.
10. Clear IRQSTAT[BRR].
11. Check SYSCTL2[EXTN] to be cleared.
12. Check SYSCTL2[SAMPCLKSEL], Sampling Clock Select. It's set value
    indicate tuning procedure success, and clear indicate failure.
    In case of tuning failure, fixed sampling scheme could be used by
    clearing TBCTL[TB_EN].

Fixes: b1f378ab ("mmc: sdhci-of-esdhc: add erratum A008171 support")
Signed-off-by: Yinbo Zhu <yinbo.zhu@nxp.com>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>