mirror of
https://github.com/lupyuen/pinephone-nuttx.git
synced 2025-01-12 20:58:34 +08:00
244 lines
8.6 KiB
Zig
244 lines
8.6 KiB
Zig
//***************************************************************************
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//
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// Licensed to the Apache Software Foundation (ASF) under one or more
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// contributor license agreements. See the NOTICE file distributed with
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// this work for additional information regarding copyright ownership. The
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// ASF licenses this file to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance with the
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// License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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//
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//***************************************************************************
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//! PinePhone Display Backlight Driver for Apache NuttX RTOS
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//! See https://lupyuen.github.io/articles/de#appendix-display-backlight
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//! "A64 Page ???" refers to Allwinner A64 User Manual: https://github.com/lupyuen/pinephone-nuttx/releases/download/doc/Allwinner_A64_User_Manual_V1.1.pdf
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/// Import the Zig Standard Library
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const std = @import("std");
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/// Import NuttX Functions from C
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const c = @cImport({
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// NuttX Defines
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@cDefine("__NuttX__", "");
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@cDefine("NDEBUG", "");
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@cDefine("FAR", "");
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// NuttX Header Files
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@cInclude("arch/types.h");
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@cInclude("../../nuttx/include/limits.h");
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@cInclude("nuttx/config.h");
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@cInclude("inttypes.h");
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@cInclude("unistd.h");
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@cInclude("stdlib.h");
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@cInclude("stdio.h");
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});
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/// PIO Base Address (CPUx-PORT) (A64 Page 376)
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const PIO_BASE_ADDRESS = 0x01C2_0800;
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/// PWM Base Address (CPUx-PWM?) (A64 Page 194)
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const PWM_BASE_ADDRESS = 0x01C2_1400;
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/// R_PIO Base Address (CPUs-PORT) (A64 Page 410)
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const R_PIO_BASE_ADDRESS = 0x01F0_2C00;
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/// R_PWM Base Address (CPUs-PWM?) (CPUs Domain, A64 Page 256)
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const R_PWM_BASE_ADDRESS = 0x01F0_3800;
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/// Turn on PinePhone Display Backlight.
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/// Based on https://lupyuen.github.io/articles/de#appendix-display-backlight
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pub export fn backlight_enable(
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percent: u32 // Percent brightness
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) void {
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debug("backlight_enable: start, percent={}", .{ percent });
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defer { debug("backlight_enable: end", .{}); }
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// Configure PL10 for PWM
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// Register PL_CFG1_REG (Port L Configure Register 1)
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// At R_PIO Offset 4 (A64 Page 412)
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// Set PL10_SELECT (Bits 8 to 10) to 2 (S_PWM)
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debug("Configure PL10 for PWM", .{});
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const PL_CFG1_REG = R_PIO_BASE_ADDRESS + 4;
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comptime { assert(PL_CFG1_REG == 0x1f02c04); }
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modreg32(2 << 8, 0b111 << 8, PL_CFG1_REG);
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// Disable R_PWM (Undocumented)
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// Register R_PWM_CTRL_REG? (R_PWM Control Register?)
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// At R_PWM Offset 0 (A64 Page 194)
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// Set SCLK_CH0_GATING (Bit 6) to 0 (Mask)
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debug("Disable R_PWM", .{});
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const R_PWM_CTRL_REG = R_PWM_BASE_ADDRESS + 0;
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comptime { assert(R_PWM_CTRL_REG == 0x1f03800); }
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modreg32(0, 1 << 6, R_PWM_CTRL_REG);
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// Configure R_PWM Period (Undocumented)
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// Register R_PWM_CH0_PERIOD? (R_PWM Channel 0 Period Register?)
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// At R_PWM Offset 4 (A64 Page 195)
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// PWM_CH0_ENTIRE_CYS (Upper 16 Bits) = Period (0x4af)
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// PWM_CH0_ENTIRE_ACT_CYS (Lower 16 Bits) = Period * Percent / 100 (0x0437)
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// Period = 1199 (Cycles of PWM Clock)
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// Percent = 90 (90% Brightness)
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debug("Configure R_PWM Period", .{});
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const R_PWM_CH0_PERIOD = R_PWM_BASE_ADDRESS + 4;
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comptime { assert(R_PWM_CH0_PERIOD == 0x1f03804); }
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const PERIOD = 1199;
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const PERCENT = 90;
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const PWM_CH0_ENTIRE_CYS: u32 = PERIOD << 16;
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const PWM_CH0_ENTIRE_ACT_CYS: u16 = PERIOD * PERCENT / 100;
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const val = PWM_CH0_ENTIRE_CYS
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| PWM_CH0_ENTIRE_ACT_CYS;
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comptime { assert(val == 0x4af0437); }
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putreg32(val, R_PWM_CH0_PERIOD);
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assert(percent == PERCENT);
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// Enable R_PWM (Undocumented)
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// Register R_PWM_CTRL_REG? (R_PWM Control Register?)
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// At R_PWM Offset 0 (A64 Page 194)
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// Set SCLK_CH0_GATING (Bit 6) to 1 (Pass)
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// Set PWM_CH0_EN (Bit 4) to 1 (Enable)
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// Set PWM_CH0_PRESCAL (Bits 0 to 3) to 0b1111 (Prescalar 1)
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debug("Enable R_PWM", .{});
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comptime { assert(R_PWM_CTRL_REG == 0x1f03800); }
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const SCLK_CH0_GATING: u7 = 1 << 6;
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const PWM_CH0_EN: u5 = 1 << 4;
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const PWM_CH0_PRESCAL: u4 = 0b1111 << 0;
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const ctrl = SCLK_CH0_GATING
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| PWM_CH0_EN
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| PWM_CH0_PRESCAL;
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comptime { assert(ctrl == 0x5f); }
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putreg32(ctrl, R_PWM_CTRL_REG);
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// Configure PH10 for Output
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// Register PH_CFG1_REG (PH Configure Register 1)
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// At PIO Offset 0x100 (A64 Page 401)
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// Set PH10_SELECT (Bits 8 to 10) to 1 (Output)
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debug("Configure PH10 for Output", .{});
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const PH_CFG1_REG = PIO_BASE_ADDRESS + 0x100;
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comptime { assert(PH_CFG1_REG == 0x1c20900); }
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const PH10_SELECT: u11 = 0b001 << 8;
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const PH10_MASK: u11 = 0b111 << 8;
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comptime { assert(PH10_SELECT == 0x100); }
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comptime { assert(PH10_MASK == 0x700); }
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modreg32(PH10_SELECT, PH10_MASK, PH_CFG1_REG);
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// Set PH10 to High
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// Register PH_DATA_REG (PH Data Register)
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// At PIO Offset 0x10C (A64 Page 403)
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// Set PH10 (Bit 10) to 1 (High)
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debug("Set PH10 to High", .{});
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const PH_DATA_REG = PIO_BASE_ADDRESS + 0x10C;
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comptime { assert(PH_DATA_REG == 0x1c2090c); }
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const PH10: u11 = 1 << 10;
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modreg32(PH10, PH10, PH_DATA_REG);
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}
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/// Modify the specified bits in a memory mapped register.
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/// Note: Parameters are different from modifyreg32
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/// Based on https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_arch.h#L473
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fn modreg32(
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comptime val: u32, // Bits to set, like (1 << bit)
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comptime mask: u32, // Bits to clear, like (1 << bit)
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addr: u64 // Address to modify
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) void {
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comptime { assert(val & mask == val); }
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debug(" *0x{x}: clear 0x{x}, set 0x{x}", .{ addr, mask, val & mask });
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putreg32(
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(getreg32(addr) & ~(mask))
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| ((val) & (mask)),
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(addr)
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);
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}
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/// Get the 32-bit value at the address
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fn getreg32(addr: u64) u32 {
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const ptr = @intToPtr(*const volatile u32, addr);
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return ptr.*;
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}
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/// Set the 32-bit value at the address
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fn putreg32(val: u32, addr: u64) void {
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if (enableLog) { debug(" *0x{x} = 0x{x}", .{ addr, val }); }
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const ptr = @intToPtr(*volatile u32, addr);
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ptr.* = val;
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}
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/// Set to False to disable log
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var enableLog = true;
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///////////////////////////////////////////////////////////////////////////////
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// Panic Handler
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/// Called by Zig when it hits a Panic. We print the Panic Message, Stack Trace and halt. See
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/// https://andrewkelley.me/post/zig-stack-traces-kernel-panic-bare-bones-os.html
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/// https://github.com/ziglang/zig/blob/master/lib/std/builtin.zig#L763-L847
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pub fn panic(
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message: []const u8,
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_stack_trace: ?*std.builtin.StackTrace
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) noreturn {
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// Print the Panic Message
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_ = _stack_trace;
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_ = puts("\n!ZIG PANIC!");
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_ = puts(@ptrCast([*c]const u8, message));
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// Print the Stack Trace
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_ = puts("Stack Trace:");
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var it = std.debug.StackIterator.init(@returnAddress(), null);
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while (it.next()) |return_address| {
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_ = printf("%p\n", return_address);
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}
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// Halt
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c.exit(1);
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}
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///////////////////////////////////////////////////////////////////////////////
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// Logging
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/// Called by Zig for `std.log.debug`, `std.log.info`, `std.log.err`, ...
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/// https://gist.github.com/leecannon/d6f5d7e5af5881c466161270347ce84d
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pub fn log(
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comptime _message_level: std.log.Level,
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comptime _scope: @Type(.EnumLiteral),
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comptime format: []const u8,
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args: anytype,
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) void {
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_ = _message_level;
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_ = _scope;
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// Format the message
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var buf: [100]u8 = undefined; // Limit to 100 chars
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var slice = std.fmt.bufPrint(&buf, format, args)
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catch { _ = puts("*** log error: buf too small"); return; };
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// Terminate the formatted message with a null
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var buf2: [buf.len + 1 : 0]u8 = undefined;
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std.mem.copy(
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u8,
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buf2[0..slice.len],
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slice[0..slice.len]
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);
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buf2[slice.len] = 0;
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// Print the formatted message
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_ = puts(&buf2);
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}
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///////////////////////////////////////////////////////////////////////////////
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// Imported Functions and Variables
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/// For safety, we import these functions ourselves to enforce Null-Terminated Strings.
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/// We changed `[*c]const u8` to `[*:0]const u8`
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extern fn printf(format: [*:0]const u8, ...) c_int;
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extern fn puts(str: [*:0]const u8) c_int;
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/// Aliases for Zig Standard Library
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const assert = std.debug.assert;
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const debug = std.log.debug;
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