1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright © 2013-2021 Intel Corporation 4 * 5 * LPT/WPT IOSF sideband. 6 */ 7 8 #include <drm/drm_print.h> 9 10 #include "intel_de.h" 11 #include "intel_display_core.h" 12 #include "intel_sbi.h" 13 #include "intel_sbi_regs.h" 14 15 /* SBI access */ 16 static int intel_sbi_rw(struct intel_display *display, u16 reg, 17 enum intel_sbi_destination destination, 18 u32 *val, bool is_read) 19 { 20 u32 cmd; 21 22 lockdep_assert_held(&display->sbi.lock); 23 24 if (intel_de_wait_fw(display, SBI_CTL_STAT, SBI_STATUS_MASK, SBI_STATUS_READY, 100, NULL)) { 25 drm_err(display->drm, "timeout waiting for SBI to become ready\n"); 26 return -EBUSY; 27 } 28 29 intel_de_write_fw(display, SBI_ADDR, SBI_ADDR_VALUE(reg)); 30 intel_de_write_fw(display, SBI_DATA, is_read ? 0 : *val); 31 32 if (destination == SBI_ICLK) 33 cmd = SBI_CTL_DEST_ICLK | SBI_CTL_OP_CRRD; 34 else 35 cmd = SBI_CTL_DEST_MPHY | SBI_CTL_OP_IORD; 36 if (!is_read) 37 cmd |= SBI_CTL_OP_WR; 38 intel_de_write_fw(display, SBI_CTL_STAT, cmd | SBI_STATUS_BUSY); 39 40 if (intel_de_wait_fw(display, SBI_CTL_STAT, SBI_STATUS_MASK, SBI_STATUS_READY, 100, &cmd)) { 41 drm_err(display->drm, "timeout waiting for SBI to complete read\n"); 42 return -ETIMEDOUT; 43 } 44 45 if (cmd & SBI_RESPONSE_FAIL) { 46 drm_err(display->drm, "error during SBI read of reg %x\n", reg); 47 return -ENXIO; 48 } 49 50 if (is_read) 51 *val = intel_de_read_fw(display, SBI_DATA); 52 53 return 0; 54 } 55 56 void intel_sbi_lock(struct intel_display *display) 57 { 58 mutex_lock(&display->sbi.lock); 59 } 60 61 void intel_sbi_unlock(struct intel_display *display) 62 { 63 mutex_unlock(&display->sbi.lock); 64 } 65 66 u32 intel_sbi_read(struct intel_display *display, u16 reg, 67 enum intel_sbi_destination destination) 68 { 69 u32 result = 0; 70 71 intel_sbi_rw(display, reg, destination, &result, true); 72 73 return result; 74 } 75 76 void intel_sbi_write(struct intel_display *display, u16 reg, u32 value, 77 enum intel_sbi_destination destination) 78 { 79 intel_sbi_rw(display, reg, destination, &value, false); 80 } 81 82 void intel_sbi_init(struct intel_display *display) 83 { 84 mutex_init(&display->sbi.lock); 85 } 86 87 void intel_sbi_fini(struct intel_display *display) 88 { 89 mutex_destroy(&display->sbi.lock); 90 } 91