169 lines
3.7 KiB
C
169 lines
3.7 KiB
C
/*
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* Copyright (c) 2017 Intel Corporation
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*
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* Intel Mobile Internet Devices (MID) based on Intel Atom SoCs have few
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* microcontrollers inside to do some auxiliary tasks. One of such
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* microcontroller is System Controller Unit (SCU) which, in particular,
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* is servicing watchdog and controlling system reset function.
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*
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* This driver enables IPC channel to SCU.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <dm.h>
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#include <regmap.h>
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#include <syscon.h>
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#include <asm/cpu.h>
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#include <asm/scu.h>
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#include <linux/errno.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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/* SCU register map */
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struct ipc_regs {
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u32 cmd;
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u32 status;
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u32 sptr;
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u32 dptr;
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u32 reserved[28];
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u32 wbuf[4];
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u32 rbuf[4];
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};
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struct scu {
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struct ipc_regs *regs;
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};
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/**
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* scu_ipc_send_command() - send command to SCU
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* @regs: register map of SCU
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* @cmd: command
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*
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* Command Register (Write Only):
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* A write to this register results in an interrupt to the SCU core processor
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* Format:
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* |rfu2(8) | size(8) | command id(4) | rfu1(3) | ioc(1) | command(8)|
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*/
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static void scu_ipc_send_command(struct ipc_regs *regs, u32 cmd)
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{
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writel(cmd, ®s->cmd);
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}
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/**
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* scu_ipc_check_status() - check status of last command
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* @regs: register map of SCU
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*
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* Status Register (Read Only):
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* Driver will read this register to get the ready/busy status of the IPC
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* block and error status of the IPC command that was just processed by SCU
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* Format:
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* |rfu3(8)|error code(8)|initiator id(8)|cmd id(4)|rfu1(2)|error(1)|busy(1)|
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*/
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static int scu_ipc_check_status(struct ipc_regs *regs)
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{
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int loop_count = 100000;
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int status;
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do {
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status = readl(®s->status);
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if (!(status & BIT(0)))
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break;
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udelay(1);
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} while (--loop_count);
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if (!loop_count)
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return -ETIMEDOUT;
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if (status & BIT(1)) {
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printf("%s() status=0x%08x\n", __func__, status);
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return -EIO;
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}
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return 0;
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}
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static int scu_ipc_cmd(struct ipc_regs *regs, u32 cmd, u32 sub,
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u32 *in, int inlen, u32 *out, int outlen)
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{
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int i, err;
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for (i = 0; i < inlen; i++)
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writel(*in++, ®s->wbuf[i]);
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scu_ipc_send_command(regs, (inlen << 16) | (sub << 12) | cmd);
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err = scu_ipc_check_status(regs);
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if (!err) {
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for (i = 0; i < outlen; i++)
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*out++ = readl(®s->rbuf[i]);
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}
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return err;
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}
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/**
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* scu_ipc_simple_command() - send a simple command
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* @cmd: command
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* @sub: sub type
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*
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* Issue a simple command to the SCU. Do not use this interface if
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* you must then access data as any data values may be overwritten
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* by another SCU access by the time this function returns.
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*
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* This function may sleep. Locking for SCU accesses is handled for
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* the caller.
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*/
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int scu_ipc_simple_command(u32 cmd, u32 sub)
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{
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struct scu *scu;
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struct udevice *dev;
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int ret;
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ret = syscon_get_by_driver_data(X86_SYSCON_SCU, &dev);
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if (ret)
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return ret;
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scu = dev_get_priv(dev);
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scu_ipc_send_command(scu->regs, sub << 12 | cmd);
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return scu_ipc_check_status(scu->regs);
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}
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int scu_ipc_command(u32 cmd, u32 sub, u32 *in, int inlen, u32 *out, int outlen)
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{
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struct scu *scu;
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struct udevice *dev;
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int ret;
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ret = syscon_get_by_driver_data(X86_SYSCON_SCU, &dev);
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if (ret)
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return ret;
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scu = dev_get_priv(dev);
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return scu_ipc_cmd(scu->regs, cmd, sub, in, inlen, out, outlen);
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}
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static int scu_ipc_probe(struct udevice *dev)
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{
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struct scu *scu = dev_get_priv(dev);
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scu->regs = syscon_get_first_range(X86_SYSCON_SCU);
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return 0;
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}
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static const struct udevice_id scu_ipc_match[] = {
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{ .compatible = "intel,scu-ipc", .data = X86_SYSCON_SCU },
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{ /* sentinel */ }
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};
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U_BOOT_DRIVER(scu_ipc) = {
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.name = "scu_ipc",
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.id = UCLASS_SYSCON,
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.of_match = scu_ipc_match,
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.probe = scu_ipc_probe,
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.priv_auto_alloc_size = sizeof(struct scu),
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};
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