// SPDX-License-Identifier: GPL-2.0
/*
* Driver for the Intel SCU IPC mechanism
*
* (C) Copyright 2008-2010,2015 Intel Corporation
* Author: Sreedhara DS (sreedhara.ds@intel.com)
*
* SCU running in ARC processor communicates with other entity running in IA
* core through IPC mechanism which in turn messaging between IA core ad SCU.
* SCU has two IPC mechanism IPC-1 and IPC-2. IPC-1 is used between IA32 and
* SCU where IPC-2 is used between P-Unit and SCU. This driver delas with
* IPC-1 Driver provides an API for power control unit registers (e.g. MSIC)
* along with other APIs.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/intel_scu_ipc.h>
/* IPC defines the following message types */
#define IPCMSG_PCNTRL 0xff /* Power controller unit read/write */
/* Command id associated with message IPCMSG_PCNTRL */
#define IPC_CMD_PCNTRL_W 0 /* Register write */
#define IPC_CMD_PCNTRL_R 1 /* Register read */
#define IPC_CMD_PCNTRL_M 2 /* Register read-modify-write */
/*
* IPC register summary
*
* IPC register blocks are memory mapped at fixed address of PCI BAR 0.
* To read or write information to the SCU, driver writes to IPC-1 memory
* mapped registers. The following is the IPC mechanism
*
* 1. IA core cDMI interface claims this transaction and converts it to a
* Transaction Layer Packet (TLP) message which is sent across the cDMI.
*
* 2. South Complex cDMI block receives this message and writes it to
* the IPC-1 register block, causing an interrupt to the SCU
*
* 3. SCU firmware decodes this interrupt and IPC message and the appropriate
* message handler is called within firmware.
*/
#define IPC_WWBUF_SIZE 20 /* IPC Write buffer Size */
#define IPC_RWBUF_SIZE 20 /* IPC Read buffer Size */
#define IPC_IOC 0x100 /* IPC command register IOC bit */
struct intel_scu_ipc_dev {
struct device dev;
struct resource mem;
struct module *owner;
int irq;
void __iomem *ipc_base;
struct completion cmd_complete;
};
#define IPC_STATUS 0x04
#define IPC_STATUS_IRQ BIT(2)
#define IPC_STATUS_ERR BIT(1)
#define IPC_STATUS_BUSY BIT(0)
/*
* IPC Write/Read Buffers:
* 16 byte buffer for sending and receiving data to and from SCU.
*/
#define IPC_WRITE_BUFFER 0x80
#define IPC_READ_BUFFER 0x90
/* Timeout in jiffies */
#define IPC_TIMEOUT (10 * HZ)
static struct intel_scu_ipc_dev *ipcdev; /* Only one for now */
static DEFINE_MUTEX(ipclock); /* lock used to prevent multiple call to SCU */
static struct class intel_scu_ipc_class = {
.name = "intel_scu_ipc",
.owner = THIS_MODULE,
};
/**
* intel_scu_ipc_dev_get() - Get SCU IPC instance
*
* The recommended new API takes SCU IPC instance as parameter and this
* function can be called by driver to get the instance. This also makes
* sure the driver providing the IPC functionality cannot be unloaded
* while the caller has the instance.
*
* Call intel_scu_ipc_dev_put() to release the instance.
*
* Returns %NULL if SCU IPC is not currently available.
*/
struct intel_scu_ipc_dev *intel_scu_ipc_dev_get(void)
{
struct intel_scu_ipc_dev *scu = NULL;
mutex_lock(&ipclock);
if (ipcdev) {
get_device(&ipcdev->dev);
/*
* Prevent the IPC provider from being unloaded while it
* is being used.
*/
if (!try_module_get(ipcdev->owner))
put_device(&ipcdev->dev);
else
scu = ipcdev;
}
mutex_unlock(&ipclock);
return scu;
}
EXPORT_SYMBOL_GPL(intel_scu_ipc_dev_get);
/**
* intel_scu_ipc_dev_put() - Put SCU IPC instance
* @scu: SCU IPC instance
*
* This function releases the SCU IPC instance retrieved from
* intel_scu_ipc_dev_get() and allows the driver providing IPC to be
* unloaded.
*/
void intel_scu_ipc_dev_put(struct intel_scu_ipc_dev *scu)
{
if (scu) {
module_put(scu->owner);
put_device(&scu->dev);
}
}
EXPORT_SYMBOL_GPL(intel_scu_ipc_dev_put);
struct intel_scu_ipc_devres {
struct intel_scu_ipc_dev *scu;
};
static void devm_intel_scu_ipc_dev_release(struct device *dev, void *res)
{
struct intel_scu_ipc_devres *dr = res;
struct intel_scu_ipc_dev *scu = dr->scu;
intel_scu_ipc_dev_put(scu);
}
/**
* devm_intel_scu_ipc_dev_get() - Allocate managed SCU IPC device
* @dev: Device requesting the SCU IPC device
*
* The recommended new API takes SCU IPC instance as parameter and this
* function can be called by driver to get the instance. This also makes
* sure the driver providing the IPC functionality cannot be unloaded
* while the caller has the instance.
*
* Returns %NULL if SCU IPC is not currently available.
*/
struct intel_scu_ipc_dev *devm_intel_scu_ipc_dev_get(struct device *dev)
{
struct intel_scu_ipc_devres *dr;
struct intel_scu_ipc_dev *scu;
dr = devres_alloc(devm_intel_scu_ipc_dev_release, sizeof(*dr), GFP_KERNEL);
if (!dr)
return NULL;
scu = intel_scu_ipc_dev_get();
if (!scu) {
devres_free(dr);
return NULL;
}
dr->scu = scu;
devres_add(dev, dr);
return scu;
}
EXPORT_SYMBOL_GPL(devm_intel_scu_ipc_dev_get);
/*
* Send ipc command
* Command Register (Write Only):
* A write to this register results in an interrupt to the SCU core processor
* Format:
* |rfu2(8) | size(8) | command id(4) | rfu1(3) | ioc(1) | command(8)|
*/
static inline void ipc_command(struct intel_scu_ipc_dev *scu, u32 cmd)
{
reinit_completion(&scu->cmd_complete);
writel(cmd | IPC_IOC, scu->ipc_base);
}
/*
* Write ipc data
* IPC Write Buffer (Write Only):
* 16-byte buffer for sending data associated with IPC command to
* SCU. Size of the data is specified in the IPC_COMMAND_REG register
*/
static inline void ipc_data_writel(struct intel_scu_ipc_dev *scu, u32 data, u32 offset)
{
writel(data, scu->ipc_base + IPC_WRITE_BUFFER + offset);
}
/*
* Status Register (Read Only):
* Driver will read this register to get the ready/busy status of the IPC
* block and error status of the IPC command that was just processed by SCU
* Format:
* |rfu3(8)|error code(8)|initiator id(8)|cmd id(4)|rfu1(2)|error(1)|busy(1)|
*/
static inline u8 ipc_read_status(struct intel_scu_ipc_dev *scu)
{
return __raw_readl(scu->ipc_base + IPC_STATUS);
}
/* Read ipc byte data */
static inline u8 ipc_data_readb(struct intel_scu_ipc_dev *scu, u32 offset)
{
return readb(scu->ipc_base + IPC_READ_BUFFER + offset);
}
/* Read ipc u32 data */
static inline u32 ipc_data_readl(struct intel_scu_ipc_dev *scu, u32 offset)
{
return readl(scu->ipc_base + IPC_READ_BUFFER + offset);
}
/* Wait till scu status is busy */
static inline int busy_loop(struct intel_scu_ipc_dev *scu)
{
unsigned long end = jiffies + IPC_TIMEOUT;
do {
u32 status;
status = ipc_read_status(scu);
if (!(status & IPC_STATUS_BUSY))
return (status & IPC_STATUS_ERR) ? -EIO : 0;
usleep_range(50, 100);
} while (time_before(jiffies, end));
return -ETIMEDOUT;
}
/* Wait till ipc ioc interrupt is received or timeout in 10 HZ */
static inline int ipc_wait_for_interrupt(struct intel_scu_ipc_dev *scu)
{
int status;
if (!wait_for_completion_timeout(&scu->cmd_complete, IPC_TIMEOUT))
return -ETIMEDOUT;
status = ipc_read_status(scu);
if (status & IPC_STATUS_ERR)
return -EIO;
return 0;
}
static int intel_scu_ipc_check_status(struct intel_scu_ipc_dev *scu)
{
return scu->irq > 0 ? ipc_wait_for_interrupt(scu) : busy_loop(scu);
}
/* Read/Write power control(PMIC in Langwell, MSIC in PenWell) registers */
static int pwr_reg_rdwr(struct intel_scu_ipc_dev *scu, u16 *addr, u8 *data,
u32 count, u32 op, u32 id)
{
int nc;
u32 offset = 0;
int err;
u8 cbuf[IPC_WWBUF_SIZE];
u32 *wbuf = (u32 *)&cbuf;
memset(cbuf, 0, sizeof(cbuf));
mutex_lock(&ipclock);
if (!scu)
scu = ipcdev;
if (!scu) {
mutex_unlock(&ipclock);
return -ENODEV;
}
for (nc = 0; nc < count; nc++, offset += 2) {
cbuf[offset] = addr[nc];
cbuf[offset + 1] = addr[nc] >> 8;
}
if (id == IPC_CMD_PCNTRL_R) {
for (nc = 0, offset = 0; nc < count; nc++, offset += 4)
ipc_data_writel(scu, wbuf[nc], offset);
ipc_command(scu, (count * 2) << 16 | id << 12 | 0 << 8 | op);
} else if (id == IPC_CMD_PCNTRL_W) {
for (nc = 0; nc < count; nc++, offset += 1)
cbuf[offset] = data[nc];
for (nc = 0, offset = 0; nc < count; nc++, offset += 4)
ipc_data_writel(scu, wbuf[nc], offset);
ipc_command(scu, (count * 3) << 16 | id << 12 | 0 << 8 | op);
} else if (id == IPC_CMD_PCNTRL_M) {
cbuf[offset] = data[0];
cbuf[offset + 1] = data[1];
ipc_data_writel(scu, wbuf[0], 0); /* Write wbuff */
ipc_command(scu, 4 << 16 | id << 12 | 0 << 8 | op);
}
err = intel_scu_ipc_check_status(scu);
if (!err && id == IPC_CMD_PCNTRL_R) { /* Read rbuf */
/* Workaround: values are read as 0 without memcpy_fromio */
memcpy_fromio(cbuf, scu->ipc_base + 0x90, 16);
for (nc = 0; nc < count; nc++)
data[nc] = ipc_data_readb(scu, nc);
}
mutex_unlock(&ipclock);
return err;
}
/**
* intel_scu_ipc_dev_ioread8() - Read a byte via the SCU
* @scu: Optional SCU IPC instance
* @addr: Register on SCU
* @data: Return pointer for read byte
*
* Read a single register. Returns %0 on success or an error code. All
* locking between SCU accesses is handled for the caller.
*
* This function may sleep.
*/
int intel_scu_ipc_dev_ioread8(struct intel_scu_ipc_dev *scu, u16 addr, u8 *data)
{
return pwr_reg_rdwr(scu, &addr, data, 1, IPCMSG_PCNTRL, IPC_CMD_PCNTRL_R);
}
EXPORT_SYMBOL(intel_scu_ipc_dev_ioread8);
/**
* intel_scu_ipc_dev_iowrite8() - Write a byte via the SCU
* @scu: Optional SCU IPC instance
* @addr: Register on SCU
* @data: Byte to write
*
* Write a single register. Returns %0 on success or an error code. All
* locking between SCU accesses is handled for the caller.
*
* This function may sleep.
*/
int intel_scu_ipc_dev_iowrite8(struct intel_scu_ipc_dev *scu, u16 addr, u8 data)
{
return pwr_reg_rdwr(scu, &addr, &data, 1, IPCMSG_PCNTRL, IPC_CMD_PCNTRL_W);
}
EXPORT_SYMBOL(intel_scu_ipc_dev_iowrite8);
/**
* intel_scu_ipc_dev_readv() - Read a set of registers
* @scu: Optional SCU IPC instance
* @addr: Register list
* @data: Bytes to return
* @len: Length of array
*
* Read registers. Returns %0 on success or an error code. All locking
* between SCU accesses is handled for the caller.
*
* The largest array length permitted by the hardware is 5 items.
*
* This function may sleep.
*/
int intel_scu_ipc_dev_readv(struct intel_scu_ipc_dev *scu, u16 *addr, u8 *data,
size_t len)
{
return pwr_reg_rdwr(scu, addr, data, len, IPCMSG_PCNTRL, IPC_CMD_PCNTRL_R);
}
EXPORT_SYMBOL(intel_scu_ipc_dev_readv);
/**
* intel_scu_ipc_dev_writev() - Write a set of registers
* @scu: Optional SCU IPC instance
* @addr: Register list
* @data: Bytes to write
* @len: Length of array
*
* Write registers. Returns %0 on success or an error code. All locking
* between SCU accesses is handled for the caller.
*
* The largest array length permitted by the hardware is 5 items.
*
* This function may sleep.
*/
int intel_scu_ipc_dev_writev(struct intel_scu_ipc_dev *scu, u16 *addr, u8 *data,
size_t len)
{
return pwr_reg_rdwr(scu, addr, data, len, IPCMSG_PCNTRL, IPC_CMD_PCNTRL_W);
}
EXPORT_SYMBOL(intel_scu_ipc_dev_writev);
/**
* intel_scu_ipc_dev_update() - Update a register
* @scu: Optional SCU IPC instance
* @addr: Register address
* @data: Bits to update
* @mask: Mask of bits to update
*
* Read-modify-write power control unit register. The first data argument
* must be register value and second is mask value mask is a bitmap that
* indicates which bits to update. %0 = masked. Don't modify this bit, %1 =
* modify this bit. returns %0 on success or an error code.
*
* This function may sleep. Locking between SCU accesses is handled
* for the caller.
*/
int intel_scu_ipc_dev_update(struct intel_scu_ipc_dev *scu, u16 addr, u8 data,
u8 mask)
{
u8 tmp[2] = { data, mask };
return pwr_reg_rdwr(scu, &addr, tmp, 1, IPCMSG_PCNTRL, IPC_CMD_PCNTRL_M);
}
EXPORT_SYMBOL(intel_scu_ipc_dev_update);
/**
* intel_scu_ipc_dev_simple_command() - Send a simple command
* @scu: Optional SCU IPC instance
* @cmd: Command
* @sub: Sub type
*
* Issue a simple command to the SCU. Do not use this interface if you must
* then access data as any data values may be overwritten by another SCU
* access by the time this function returns.
*
* This function may sleep. Locking for SCU accesses is handled for the
* caller.
*/
int intel_scu_ipc_dev_simple_command(struct intel_scu_ipc_dev *scu, int cmd,
int sub)
{
u32 cmdval;
int err;
mutex_lock(&ipclock);
if (!scu)
scu = ipcdev;
if (!scu) {
mutex_unlock(&ipclock);
return -ENODEV;
}
scu = ipcdev;
cmdval = sub << 12 | cmd;
ipc_command(scu, cmdval);
err = intel_scu_ipc_check_status(scu);
mutex_unlock(&ipclock);
if (err)
dev_err(&scu->dev, "IPC command %#x failed with %d\n", cmdval, err);
return err;
}
EXPORT_SYMBOL(intel_scu_ipc_dev_simple_command);
/**
* intel_scu_ipc_dev_command_with_size() - Command with data
* @scu: Optional SCU IPC instance
* @cmd: Command
* @sub: Sub type
* @in: Input data
* @inlen: Input length in bytes
* @size: Input size written to the IPC command register in whatever
* units (dword, byte) the particular firmware requires. Normally
* should be the same as @inlen.
* @out: Output data
* @outlen: Output length in bytes
*
* Issue a command to the SCU which involves data transfers. Do the
* data copies under the lock but leave it for the caller to interpret.
*/
int intel_scu_ipc_dev_command_with_size(struct intel_scu_ipc_dev *scu, int cmd,
int sub, const void *in, size_t inlen,
size_t size, void *out, size_t outlen)
{
size_t outbuflen = DIV_ROUND_UP(outlen, sizeof(u32));
size_t inbuflen = DIV_ROUND_UP(inlen, sizeof(u32));
u32 cmdval, inbuf[4] = {};
int i, err;
if (inbuflen > 4 || outbuflen > 4)
return -EINVAL;
mutex_lock(&ipclock);
if (!scu)
scu = ipcdev;
if (!scu) {
mutex_unlock(&ipclock);
return -ENODEV;
}
memcpy(inbuf, in, inlen);
for (i = 0; i < inbuflen; i++)
ipc_data_writel(scu, inbuf[i], 4 * i);
cmdval = (size << 16) | (sub << 12) | cmd;
ipc_command(scu, cmdval);
err = intel_scu_ipc_check_status(scu);
if (!err) {
u32 outbuf[4] = {};
for (i = 0; i < outbuflen; i++)
outbuf[i] = ipc_data_readl(scu, 4 * i);
memcpy(out, outbuf, outlen);
}
mutex_unlock(&ipclock);
if (err)
dev_err(&scu->dev, "IPC command %#x failed with %d\n", cmdval, err);
return err;
}
EXPORT_SYMBOL(intel_scu_ipc_dev_command_with_size);
/*
* Interrupt handler gets called when ioc bit of IPC_COMMAND_REG set to 1
* When ioc bit is set to 1, caller api must wait for interrupt handler called
* which in turn unlocks the caller api. Currently this is not used
*
* This is edge triggered so we need take no action to clear anything
*/
static irqreturn_t ioc(int irq, void *dev_id)
{
struct intel_scu_ipc_dev *scu = dev_id;
int status = ipc_read_status(scu);
writel(status | IPC_STATUS_IRQ, scu->ipc_base + IPC_STATUS);
complete(&scu->cmd_complete);
return IRQ_HANDLED;
}
static void intel_scu_ipc_release(struct device *dev)
{
struct intel_scu_ipc_dev *scu;
scu = container_of(dev, struct intel_scu_ipc_dev, dev);
if (scu->irq > 0)
free_irq(scu->irq, scu);
iounmap(scu->ipc_base);
release_mem_region(scu->mem.start, resource_size(&scu->mem));
kfree(scu);
}
/**
* __intel_scu_ipc_register() - Register SCU IPC device
* @parent: Parent device
* @scu_data: Data used to configure SCU IPC
* @owner: Module registering the SCU IPC device
*
* Call this function to register SCU IPC mechanism under @parent.
* Returns pointer to the new SCU IPC device or ERR_PTR() in case of
* failure. The caller may use the returned instance if it needs to do
* SCU IPC calls itself.
*/
struct intel_scu_ipc_dev *
__intel_scu_ipc_register(struct device *parent,
const struct intel_scu_ipc_data *scu_data,
struct module *owner)
{
int err;
struct intel_scu_ipc_dev *scu;
void __iomem *ipc_base;
mutex_lock(&ipclock);
/* We support only one IPC */
if (ipcdev) {
err = -EBUSY;
goto err_unlock;
}
scu = kzalloc(sizeof(*scu), GFP_KERNEL);
if (!scu) {
err = -ENOMEM;
goto err_unlock;
}
scu->owner = owner;
scu->dev.parent = parent;
scu->dev.class = &intel_scu_ipc_class;
scu->dev.release = intel_scu_ipc_release;
dev_set_name(&scu->dev, "intel_scu_ipc");
if (!request_mem_region(scu_data->mem.start, resource_size(&scu_data->mem),
"intel_scu_ipc")) {
err = -EBUSY;
goto err_free;
}
ipc_base = ioremap(scu_data->mem.start, resource_size(&scu_data->mem));
if (!ipc_base) {
err = -ENOMEM;
goto err_release;
}
scu->ipc_base = ipc_base;
scu->mem = scu_data->mem;
scu->irq = scu_data->irq;
init_completion(&scu->cmd_complete);
if (scu->irq > 0) {
err = request_irq(scu->irq, ioc, 0, "intel_scu_ipc", scu);
if (err)
goto err_unmap;
}
/*
* After this point intel_scu_ipc_release() takes care of
* releasing the SCU IPC resources once refcount drops to zero.
*/
err = device_register(&scu->dev);
if (err) {
put_device(&scu->dev);
goto err_unlock;
}
/* Assign device at last */
ipcdev = scu;
mutex_unlock(&ipclock);
return scu;
err_unmap:
iounmap(ipc_base);
err_release:
release_mem_region(scu_data->mem.start, resource_size(&scu_data->mem));
err_free:
kfree(scu);
err_unlock:
mutex_unlock(&ipclock);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(__intel_scu_ipc_register);
/**
* intel_scu_ipc_unregister() - Unregister SCU IPC
* @scu: SCU IPC handle
*
* This unregisters the SCU IPC device and releases the acquired
* resources once the refcount goes to zero.
*/
void intel_scu_ipc_unregister(struct intel_scu_ipc_dev *scu)
{
mutex_lock(&ipclock);
if (!WARN_ON(!ipcdev)) {
ipcdev = NULL;
device_unregister(&scu->dev);
}
mutex_unlock(&ipclock);
}
EXPORT_SYMBOL_GPL(intel_scu_ipc_unregister);
static void devm_intel_scu_ipc_unregister(struct device *dev, void *res)
{
struct intel_scu_ipc_devres *dr = res;
struct intel_scu_ipc_dev *scu = dr->scu;
intel_scu_ipc_unregister(scu);
}
/**
* __devm_intel_scu_ipc_register() - Register managed SCU IPC device
* @parent: Parent device
* @scu_data: Data used to configure SCU IPC
* @owner: Module registering the SCU IPC device
*
* Call this function to register managed SCU IPC mechanism under
* @parent. Returns pointer to the new SCU IPC device or ERR_PTR() in
* case of failure. The caller may use the returned instance if it needs
* to do SCU IPC calls itself.
*/
struct intel_scu_ipc_dev *
__devm_intel_scu_ipc_register(struct device *parent,
const struct intel_scu_ipc_data *scu_data,
struct module *owner)
{
struct intel_scu_ipc_devres *dr;
struct intel_scu_ipc_dev *scu;
dr = devres_alloc(devm_intel_scu_ipc_unregister, sizeof(*dr), GFP_KERNEL);
if (!dr)
return NULL;
scu = __intel_scu_ipc_register(parent, scu_data, owner);
if (IS_ERR(scu)) {
devres_free(dr);
return scu;
}
dr->scu = scu;
devres_add(parent, dr);
return scu;
}
EXPORT_SYMBOL_GPL(__devm_intel_scu_ipc_register);
static int __init intel_scu_ipc_init(void)
{
return class_register(&intel_scu_ipc_class);
}
subsys_initcall(intel_scu_ipc_init);
static void __exit intel_scu_ipc_exit(void)
{
class_unregister(&intel_scu_ipc_class);
}
module_exit(intel_scu_ipc_exit);