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https://github.com/brain-hackers/u-boot-brain
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![Tom Rini](/assets/img/avatar_default.png)
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
168 lines
3.7 KiB
C
168 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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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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#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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