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1// SPDX-License-Identifier: MIT2/*3 * Copyright © 2013-2021 Intel Corporation4 *5 * LPT/WPT IOSF sideband.6 */7 8#include "i915_drv.h"9#include "intel_sbi.h"10#include "i915_reg.h"11 12/* SBI access */13static int intel_sbi_rw(struct drm_i915_private *i915, u16 reg,14 enum intel_sbi_destination destination,15 u32 *val, bool is_read)16{17 struct intel_uncore *uncore = &i915->uncore;18 u32 cmd;19 20 lockdep_assert_held(&i915->sb_lock);21 22 if (intel_wait_for_register_fw(uncore,23 SBI_CTL_STAT, SBI_BUSY, 0,24 100)) {25 drm_err(&i915->drm,26 "timeout waiting for SBI to become ready\n");27 return -EBUSY;28 }29 30 intel_uncore_write_fw(uncore, SBI_ADDR, (u32)reg << 16);31 intel_uncore_write_fw(uncore, SBI_DATA, is_read ? 0 : *val);32 33 if (destination == SBI_ICLK)34 cmd = SBI_CTL_DEST_ICLK | SBI_CTL_OP_CRRD;35 else36 cmd = SBI_CTL_DEST_MPHY | SBI_CTL_OP_IORD;37 if (!is_read)38 cmd |= BIT(8);39 intel_uncore_write_fw(uncore, SBI_CTL_STAT, cmd | SBI_BUSY);40 41 if (__intel_wait_for_register_fw(uncore,42 SBI_CTL_STAT, SBI_BUSY, 0,43 100, 100, &cmd)) {44 drm_err(&i915->drm,45 "timeout waiting for SBI to complete read\n");46 return -ETIMEDOUT;47 }48 49 if (cmd & SBI_RESPONSE_FAIL) {50 drm_err(&i915->drm, "error during SBI read of reg %x\n", reg);51 return -ENXIO;52 }53 54 if (is_read)55 *val = intel_uncore_read_fw(uncore, SBI_DATA);56 57 return 0;58}59 60u32 intel_sbi_read(struct drm_i915_private *i915, u16 reg,61 enum intel_sbi_destination destination)62{63 u32 result = 0;64 65 intel_sbi_rw(i915, reg, destination, &result, true);66 67 return result;68}69 70void intel_sbi_write(struct drm_i915_private *i915, u16 reg, u32 value,71 enum intel_sbi_destination destination)72{73 intel_sbi_rw(i915, reg, destination, &value, false);74}75