From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi all,

This series applies existing SDHI tuning quirks to the Renesas RZ/G2 
family (RZ/G2H, RZ/G2N, and RZ/G2E).

The RZ/G2 series SoCs are functionally equivalent to their R-Car Gen3 
counterparts regarding the SDHI controller logic. Specifically:
- RZ/G2H (r8a774e1) matches R-Car H3-N (r8a77951)
- RZ/G2N (r8a774b1) matches R-Car M3-N (r8a77965)
- RZ/G2E (r8a774c0) matches R-Car E3 (r8a77990)

By applying the relevant bad tap quirks already used by the R-Car 
variants, we avoid unreliable tuning positions and significantly 
improve data throughput stability and performance.

The following performance improvements were observed during testing,
on eMMC with HS400 mode, using the mmc_test module for 1000 iterations
on each SoC:

SoC      |  READ BANDWIDTH (KB/s) | WRITE BANDWIDTH (KB/s) |
         |     Before -> After    |     Before -> After    |
------------------------------------------------------------
RZ/G2H   |     42500  -> 100744   |    70109 -> 72594      |
RZ/G2N   |     46680  -> 104731   |    73393 -> 74298      |
RZ/G2E   |     159472 -> 180781   |    126355 -> 127725    |

Cheers,
Prabhakar

Lad Prabhakar (3):
  mmc: renesas_sdhi: Apply bad taps quirk to RZ/G2H
  mmc: renesas_sdhi: Add SDHI quirk for RZ/G2N
  mmc: renesas_sdhi: Add SDHI quirk for RZ/G2E

 drivers/mmc/host/renesas_sdhi_internal_dmac.c | 3 +++
 1 file changed, 3 insertions(+)

-- 
2.54.0