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The I2CR has the capability to directly perform SCOM operations, circumventing the need to drive the FSI2PIB engine. Add a new driver to perform SCOM operations through the I2CR. Signed-off-by: Eddie James <eajames@linux.ibm.com> Link: https://lore.kernel.org/r/20230612195657.245125-15-eajames@linux.ibm.com Signed-off-by: Joel Stanley <joel@jms.id.au>
155 lines
3.1 KiB
C
155 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) IBM Corporation 2023 */
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/fsi.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include "fsi-master-i2cr.h"
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#include "fsi-slave.h"
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struct i2cr_scom {
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struct device dev;
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struct cdev cdev;
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struct fsi_master_i2cr *i2cr;
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};
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static loff_t i2cr_scom_llseek(struct file *file, loff_t offset, int whence)
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{
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switch (whence) {
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case SEEK_CUR:
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break;
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case SEEK_SET:
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file->f_pos = offset;
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break;
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default:
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return -EINVAL;
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}
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return offset;
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}
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static ssize_t i2cr_scom_read(struct file *filep, char __user *buf, size_t len, loff_t *offset)
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{
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struct i2cr_scom *scom = filep->private_data;
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u64 data;
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int ret;
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if (len != sizeof(data))
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return -EINVAL;
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ret = fsi_master_i2cr_read(scom->i2cr, (u32)*offset, &data);
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if (ret)
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return ret;
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ret = copy_to_user(buf, &data, len);
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if (ret)
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return ret;
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return len;
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}
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static ssize_t i2cr_scom_write(struct file *filep, const char __user *buf, size_t len,
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loff_t *offset)
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{
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struct i2cr_scom *scom = filep->private_data;
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u64 data;
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int ret;
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if (len != sizeof(data))
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return -EINVAL;
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ret = copy_from_user(&data, buf, len);
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if (ret)
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return ret;
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ret = fsi_master_i2cr_write(scom->i2cr, (u32)*offset, data);
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if (ret)
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return ret;
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return len;
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}
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static const struct file_operations i2cr_scom_fops = {
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.owner = THIS_MODULE,
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.open = simple_open,
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.llseek = i2cr_scom_llseek,
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.read = i2cr_scom_read,
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.write = i2cr_scom_write,
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};
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static int i2cr_scom_probe(struct device *dev)
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{
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struct fsi_device *fsi_dev = to_fsi_dev(dev);
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struct i2cr_scom *scom;
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int didx;
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int ret;
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if (!is_fsi_master_i2cr(fsi_dev->slave->master))
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return -ENODEV;
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scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
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if (!scom)
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return -ENOMEM;
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scom->i2cr = to_fsi_master_i2cr(fsi_dev->slave->master);
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dev_set_drvdata(dev, scom);
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scom->dev.type = &fsi_cdev_type;
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scom->dev.parent = dev;
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device_initialize(&scom->dev);
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ret = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
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if (ret)
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return ret;
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dev_set_name(&scom->dev, "scom%d", didx);
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cdev_init(&scom->cdev, &i2cr_scom_fops);
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ret = cdev_device_add(&scom->cdev, &scom->dev);
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if (ret)
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fsi_free_minor(scom->dev.devt);
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return ret;
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}
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static int i2cr_scom_remove(struct device *dev)
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{
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struct i2cr_scom *scom = dev_get_drvdata(dev);
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cdev_device_del(&scom->cdev, &scom->dev);
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fsi_free_minor(scom->dev.devt);
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return 0;
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}
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static const struct of_device_id i2cr_scom_of_ids[] = {
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{ .compatible = "ibm,i2cr-scom" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, i2cr_scom_of_ids);
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static const struct fsi_device_id i2cr_scom_ids[] = {
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{ 0x5, FSI_VERSION_ANY },
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{ }
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};
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static struct fsi_driver i2cr_scom_driver = {
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.id_table = i2cr_scom_ids,
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.drv = {
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.name = "i2cr_scom",
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.bus = &fsi_bus_type,
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.of_match_table = i2cr_scom_of_ids,
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.probe = i2cr_scom_probe,
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.remove = i2cr_scom_remove,
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}
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};
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module_fsi_driver(i2cr_scom_driver);
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MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
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MODULE_DESCRIPTION("IBM I2C Responder SCOM driver");
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MODULE_LICENSE("GPL");
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