[PATCH 0/7] 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.

---
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-20260714.
- Ive kept patches 6 and 7 separate as they belong
  to different subsystems (SPI and memory) and may
  be applied independently.

Cheers,
Prabhakar

Lad Prabhakar (7):
  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
  spi: spi-rpc-if: Implement 200ms runtime PM autosuspend delay
  memory: renesas-rpc-if: Use runtime PM autosuspend after transfers

 drivers/memory/renesas-rpc-if.c | 87 ++++++++++++++-------------------
 drivers/spi/spi-rpc-if.c        |  4 ++
 2 files changed, 40 insertions(+), 51 deletions(-)

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2.54.0