Add support for AMD eMMC controller HS400 mode

[marius]

Summary

This patch attempts to port the following Linux change in order to add HS400 mode support for AMD eMMC 5.0 controller:
https://patchwork.kernel.org/patch/10086747/

In order to switch to HS mode from HS200 while going to HS400 mode, the tuning bit needs to be reset.

[mav]

Unfortunately I haven't touched this area for several years and don't know details of modern transfer modes.

[marius]

sys/dev/sdhci/sdhci.c

904

Given that this appears to be specific to this particular AMD ACPI-based SDHCI controller (AMD PCI-based SDHCI controllers require different workarounds according to Linux), setting MMC_CAP_MMC_HS400 in slot->host.caps should go to sdhci_acpi_attach() based on HID and UID. That way sdhci_init_slot() only needs to be changed to or in host_caps and SDHCI_QUIRK_AMD_SET_MMC_HS400 is superfluous (see also below).

1181

This function is only called once, so its 3 lines of code should be inlined in an sdhci_acpi_set_uhs_timing() (see also below) instead.

1233

Likewise, given that this workaround appears to be specific to this particular AMD ACPI-based SDHCI controller, this code should go to an sdhci_acpi_set_uhs_timing() in sdhci_acpi.c, i. e. not to sdhci_generic_set_uhs_timing(), and be based on HID and UID of this controller instead of SDHCI_QUIRK_AMD_SET_MMC_HS400. The sdhci_acpi_set_uhs_timing() needs to be hooked up as sdhci_set_uhs_timing method in sdhci_methods of sdhci_acpi.c and wrap around sdhci_generic_set_uhs_timing() (similar to amd_set_ios() being the set_ios method for this controller in the Linux sdhci-acpi.c and with amd_set_ios() wrapping around sdhci_set_ios() there).

sys/dev/sdhci/sdhci.h

336 ↗

(On Diff #49432)

This should go to sdhci_acpi.c (see also below). The space after #define needs to be a tab according to style(9).

[shreyankamartya229_gmail.com]

Made requested changes as per comments.

[shreyankamartya229_gmail.com]

sys/dev/sdhci/sdhci.c

904

Just to confirm, I take that you mean the only change in sdhci_init_slot would be to OR the host caps instead of assigning it.

1181

Done.

1233

Done.

sys/dev/sdhci/sdhci.h

336 ↗

(On Diff #49432)

Aah, sorry about that. Missed one.

[shreyankamartya229_gmail.com]

@marius : Hi, Can you please review the latest changes.

[shreyankamartya229_gmail.com]

@marius : I know that you must be really busy with the upcoming release. Please review this if possible, I've made the necessary changes that you requested in the last review.

[marius]

Close; obsoleted by r340543; thanks for the original patch!