system/fidl/ddk/protocols/sdhci.fidl

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library ddk.protocol.sdhci;

using hw.sdhci;
using zx;

enum SdhciQuirk : uint64 {
    /// This is a BCM28xx specific quirk. The bottom 8 bits of the 136
    /// bit response are normally filled by 7 CRC bits and 1 reserved bit.
    /// The BCM controller checks the CRC for us and strips it off in the
    /// process.
    /// The higher level stack expects 136B responses to be packed in a
    /// certain way so we shift all the fields back to their proper offsets.
    STRIP_RESPONSE_CRC                 = 0x1;
    /// BCM28xx quirk: The BCM28xx appears to use its internal DMA engine to
    /// perform transfers against the SD card. Normally we would use SDMA or
    /// ADMA (if the part supported it). Since this part doesn't appear to
    /// support either, we just use PIO.
    NO_DMA                             = 0x2;
    /// The bottom 8 bits of the 136 bit response are normally filled by 7 CRC bits
    /// and 1 reserved bit. Some controllers strip off the CRC.
    /// The higher level stack expects 136B responses to be packed in a certain way
    /// so we shift all the fields back to their proper offsets.
    STRIP_RESPONSE_CRC_PRESERVE_ORDER  = 0x4;
};

[Layout="ddk-protocol"]
interface Sdhci {
    // TODO: should be replaced with a generic busdev mechanism
    1: GetInterrupt() -> (zx.status s, handle<interrupt> irq);
    2: GetMmio() -> (zx.status s, handle<vmo> mmio);
    /// Gets a handle to the bus transaction initiator for the device. The caller
    /// receives ownership of the handle.
    3: GetBti(uint32 index) -> (zx.status s, handle<bti> bti);

    4: GetBaseClock() -> (uint32 clock);

    /// returns device quirks
    5: GetQuirks() -> (uint64 clock);
    /// platform specific HW reset
    6: HwReset() -> ();
};