[PATCH 0/6] RISC-V: Add eMMC support for TH1520 boards

[Drew Fustini]

This series adds support for the eMMC on the BeagleV Ahead and the
Sipeed LicheePi 4A. This allows the kernel to boot with the rootfs on
eMMC.

I tested on top of v6.6-rc2 with this config [1]. I was able to boot
both the Ahead [2] and LPi4a [3] from eMMC. The following prerequisites
are required:

  [PATCH v2] riscv: dts: thead: set dma-noncoherent to soc bus [4]

I pushed a branch [5] with this patch series and the above patch for
those that find a git branch easier to test.

Please note that only the MMC controller connected to the eMMC device
is enabled in the device trees for these two boards. I did not yet
attempt to configure and use the microSD card slot. My preference is to
address that in a future patch series.

References:
[1] https://gist.github.com/pdp7/5fbdcf2a65eb1abdd3a29d519c19cdd2
[2] https://gist.github.com/pdp7/91a801a5f8d1070c53509eda9800ad78
[3] https://gist.github.com/pdp7/1445c3c991e88fd69c60165cef65726a
[4] https://lore.kernel.org/linux-riscv/20230912072232.2455-1-jszhang@xxxxxxxxxx/
[5] https://github.com/pdp7/linux/tree/b4/th1520-mmc

Changes since RFC v2:
- ADMA mode now works correctly due to a patch from Jisheng on the list
  ("riscv: dts: thead: set dma-noncoherent to soc bus") and this commit
  from Icenowy that is now merged: 8eb8fe67e2c8 ("riscv: errata: fix
  T-Head dcache.cva encoding").
- Expose __sdhci_execute_tuning from sdhci.c so that it can be called
  from th1520_execute_tuning()
- Refactor the define macros for all the PHY related registers to make
  it easier to understand the bit fields that the code is manipulating
- Replace magic numbers in the PHY register writes with proper defines 
- Replace non_removable in dwcmshc_priv with check of mmc_host.caps
- Drop dt prop "thead,io-fixed-1v8" and instead check for existing
  properties: "mmc-ddr-1_8v", "mmc-hs200-1_8v", or "mmc-hs400-1_8v"
- Rename dt prop from "thead,pull-up" to "thead,phy-pull-up" and
  improve the description in the dt binding
- Replace pull_up_en in dwcmshc_priv with bit field in new flags field
- Create th1520_set_uhs_signaling() and call dwcmshc_set_uhs_signaling()
  from it instead of adding th1520 code to dwcmshc_set_uhs_signaling()
- Return -EIO instead of -1 upon errors in th1520_execute_tuning()

Changes in RFC v2:
https://lore.kernel.org/linux-riscv/20230724-th1520-emmc-v2-0-132ed2e2171e@xxxxxxxxxxxx/
- Expand dwcmshc_priv based on driver in the T-Head 5.10 kernel:
  delay_line, non_removable, pull_up_en, io_fixed_1v8
- New boolean property "thead,pull-up" indicates phy pull-up config
- New boolean property "thead,io-fixed-1v8" indicates that io voltage
  should be set to 1.8V during reset
- Add th1520_phy_1_8v_init() as voltage_switch op
- Add th1520_execute_tuning() as the platform_execute_tuning op
- Added th1520_sdhci_reset() as the .reset op. This function will set
  io voltage to 1.8V after calling the standard sdhci_reset() function.
- Modified dwcmshc_set_uhs_signaling() to enable SDHCI_CTRL_VDD_180 when
  io_fixed_1v8 is true
- Add many defines for register offsets and settings based on the mmc
  support in the T-Head downstream v5.10 kernel

RFC v1 series:
https://lore.kernel.org/r/20230724-th1520-emmc-v1-0-cca1b2533da2@xxxxxxxxxxxx

Signed-off-by: Drew Fustini <dfustini@xxxxxxxxxxxx>
---
Drew Fustini (6):
      dt-bindings: mmc: sdhci-of-dwcmhsc: Add T-Head TH1520 support
      mmc: sdhci: add __sdhci_execute_tuning() to header
      mmc: sdhci-of-dwcmshc: Add support for T-Head TH1520
      riscv: dts: thead: Add TH1520 mmc controller and sdhci clock
      riscv: dts: thead: Enable BeagleV Ahead eMMC controller
      riscv: dts: thead: Enable LicheePi 4A eMMC controller

 .../bindings/mmc/snps,dwcmshc-sdhci.yaml           |   4 +
 arch/riscv/boot/dts/thead/th1520-beaglev-ahead.dts |  15 +
 .../boot/dts/thead/th1520-lichee-module-4a.dtsi    |  15 +
 arch/riscv/boot/dts/thead/th1520.dtsi              |  15 +
 drivers/mmc/host/sdhci-of-dwcmshc.c                | 456 +++++++++++++++++++++
 drivers/mmc/host/sdhci.c                           |   2 +-
 drivers/mmc/host/sdhci.h                           |   1 +
 7 files changed, 507 insertions(+), 1 deletion(-)
---
base-commit: 3d01adbee80b2237c43e2e06d59e05aa243a0fe6
change-id: 20230921-th1520-mmc-518806aa55a8

Best regards,
-- 
Drew Fustini <dfustini@xxxxxxxxxxxx>