[PATCH v2 0/6] memory: renesas-rpc-if: Optimize transfer overhead and implement runtime PM autosuspend

From: Lad Prabhakar <[email protected]>

Hi all,

This patch series optimizes the Renesas RPC-IF driver by significantly
reducing software overhead in both the direct memory-mapped (dirmap) and
manual transfer paths, maximizing transaction throughput, and introducing
runtime PM autosuspend to prevent aggressive power gating during
consecutive flash operations.

v1->v2:
- Dropped `spi: spi-rpc-if: Implement 200ms runtime PM autosuspend delay`
  patch as this has been merged via SPI subsystem.

---
Performance Results:

These changes were benchmarked using flash_speed on the RZ/T2H EVK with
xSPI0/1 interfaces operating in 1S-1S-1S mode for write operations:

xSPI0(MX25LW51245G):
                 Without        With Fixes
  Write Speed:  806 KiB/s       942 KiB/s
  Read Speed:   5333 KiB/s      5361 KiB/s

xSPI1(AT25SF128A):
  Write Speed:  467 KiB/s       501 KiB/s
  Read Speed:   17964 KiB/s     18285 KiB/s


Note:
- Patches have been rebased on top of next-20260726.

Cheers,
Prabhakar

Lad Prabhakar (6):
  memory: renesas-rpc-if: Mark XSPI_CDD1BUF0 as volatile
  memory: renesas-rpc-if: Move static bridge configurations out of
    dirmap hot paths
  memory: renesas-rpc-if: Consolidate XSPI_CDTBUF0 updates in write path
  memory: renesas-rpc-if: Consolidate XSPI_CDTBUF0 updates in read path
  memory: renesas-rpc-if: Consolidate command setup register programming
  memory: renesas-rpc-if: Use runtime PM autosuspend after transfers

 drivers/memory/renesas-rpc-if.c | 87 ++++++++++++++-------------------
 1 file changed, 36 insertions(+), 51 deletions(-)

-- 
2.54.0