[PATCH linux v6 18/18] drivers/fsi: Add SCOM FSI client device driver
Alistair Popple
alistair at popple.id.au
Mon Nov 14 10:44:01 AEDT 2016
Hi Chris,
Is there a similar device driver for the CFAM/FSI that I missed? That is will
there be a chardev for read/writing FSI addresses directly (ie. a chardev to
call fsi_device_read/write)? Probably not critical for an initial release but
we will need one at some point as I'm pretty sure the cronus server for
example has get/putcfam commands as some registers aren't available via SCOM.
Regards,
Alistair
On Sun, 30 Oct 2016 05:09:20 PM christopher.lee.bostic at gmail.com wrote:
> From: Chris Bostic <cbostic at us.ibm.com>
>
> Create a simple SCOM engine device driver that reads and writes
> across an FSI bus.
>
> Signed-off-by: Chris Bostic <cbostic at us.ibm.com>
>
> ---
>
> V4 - Add put_scom and get_scom operations
>
> V5 - Add character device registration and fill in read/write
> syscalls.
>
> V6 - Add multi scom engine support. Add list of devices.
> Use file private data to store and hand off scom structures.
>
> - Add lseek, open, close
>
> - Remove data/address structure to pass from user space to
> kernel. Use offset provided by read/write and pass data
>
> - Added list setup in init and so did not add the macro
> module_fsi_driver
>
> - Global structs made static where possible.
>
> - Change from char dev to use misc device api as shown
> in examples from Jeremy Kere.
> ---
> drivers/fsi/Kconfig | 6 ++
> drivers/fsi/Makefile | 1 +
> drivers/fsi/fsi-scom.c | 238
+++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 245 insertions(+)
> create mode 100644 drivers/fsi/fsi-scom.c
>
> diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
> index b21fe3c..1fa9bc0 100644
> --- a/drivers/fsi/Kconfig
> +++ b/drivers/fsi/Kconfig
> @@ -23,6 +23,12 @@ config FSI_MASTER_GPIO
> depends on FSI
> ---help---
> This option enables a FSI master driver using GPIO lines.
> +
> +config FSI_SCOM
> + tristate "SCOM FSI client"
> + depends on FSI
> + ---help---
> + This option enables the SCOM FSI client device driver.
> endif
>
> endmenu
> diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
> index 2021ce5..3e31d9a 100644
> --- a/drivers/fsi/Makefile
> +++ b/drivers/fsi/Makefile
> @@ -2,3 +2,4 @@
> obj-$(CONFIG_FSI) += fsi-core.o
> obj-$(CONFIG_FSI_MASTER_FAKE) += fsi-master-fake.o
> obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
> +obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
> diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
> new file mode 100644
> index 0000000..27be082
> --- /dev/null
> +++ b/drivers/fsi/fsi-scom.c
> @@ -0,0 +1,238 @@
> +/*
> + * SCOM FSI Client device driver
> + *
> + * Copyright (C) IBM Corporation 2016
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERGCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/fsi.h>
> +#include <linux/module.h>
> +#include <linux/cdev.h>
> +#include <linux/delay.h>
> +#include <linux/fs.h>
> +#include <linux/uaccess.h>
> +#include <linux/slab.h>
> +#include <linux/miscdevice.h>
> +#include <linux/list.h>
> +
> +#define FSI_ENGID_SCOM 0x5
> +
> +#define SCOM_FSI2PIB_DELAY 50
> +
> +/* SCOM engine register set */
> +#define SCOM_DATA0_REG 0x00
> +#define SCOM_DATA1_REG 0x04
> +#define SCOM_CMD_REG 0x08
> +#define SCOM_RESET_REG 0x1C
> +
> +#define SCOM_RESET_CMD 0x80000000
> +#define SCOM_WRITE_CMD 0x80000000
> +
> +struct scom_device {
> + struct list_head link;
> + struct fsi_device *fsi_dev;
> + struct miscdevice mdev;
> + char name[32];
> +};
> +
> +#define to_scom_dev(x) container_of((x), struct scom_device,
mdev)
> +
> +static struct list_head scom_devices;
> +static atomic_t scom_idx = ATOMIC_INIT(0);
> +static int scom_probe(struct device *);
> +
> +static int put_scom(struct scom_device *scom_dev, uint64_t value,
> + uint32_t addr)
> +{
> + int rc;
> + uint32_t data = SCOM_RESET_CMD;
> +
> + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_RESET_REG, &data,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + data = (value >> 32) & 0xffffffff;
> + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + data = value & 0xffffffff;
> + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + data = SCOM_WRITE_CMD | addr;
> + return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
> + sizeof(uint32_t));
> +}
> +
> +static int get_scom(struct scom_device *scom_dev, uint64_t *value,
> + uint32_t addr)
> +{
> + uint32_t result, data;
> + int rc;
> +
> + udelay(SCOM_FSI2PIB_DELAY);
> +
> + data = addr;
> + rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + *value |= (uint64_t) result << 32;
> + rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result,
> + sizeof(uint32_t));
> + if (rc)
> + return rc;
> +
> + *value |= result;
> +
> + return 0;
> +}
> +
> +static loff_t scom_llseek(struct file *filep, loff_t offset, int whence)
> +{
> + if (whence != 0) /* SEEK_SET */
> + return -EINVAL;
> +
> + filep->f_pos = offset;
> + return offset;
> +}
> +
> +static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
> + loff_t *offset)
> +{
> + int rc = 0;
> + struct miscdevice *mdev =
> + (struct miscdevice *)filep->private_data;
> + struct scom_device *scom = to_scom_dev(mdev);
> + struct device *dev = &scom->fsi_dev->dev;
> + uint64_t val;
> +
> + if (len != sizeof(uint64_t))
> + return -EINVAL;
> +
> + rc = get_scom(scom, &val, *offset);
> + if (rc) {
> + dev_dbg(dev, "get_scom fail:%d\n", rc);
> + return rc;
> + }
> +
> + rc = copy_to_user(buf, &val, len);
> + if (rc)
> + dev_dbg(dev, "copy to user failed:%d\n", rc);
> +
> + return rc ? rc : len;
> +}
> +
> +static ssize_t scom_write(struct file *filep, const char __user *buf,
> + size_t len, loff_t *offset)
> +{
> + int rc = 0;
> + struct miscdevice *mdev =
> + (struct miscdevice *)filep->private_data;
> + struct scom_device *scom = to_scom_dev(mdev);
> + struct device *dev = &scom->fsi_dev->dev;
> + uint64_t val;
> +
> + if (len != sizeof(uint64_t))
> + return -EINVAL;
> +
> + rc = copy_from_user(&val, buf, len);
> + if (rc) {
> + dev_dbg(dev, "copy from user failed:%d\n", rc);
> + return -EINVAL;
> + }
> +
> + rc = put_scom(scom, val, *offset);
> + if (rc)
> + dev_dbg(dev, "put_scom failed with:%d\n", rc);
> +
> +
> + return rc ? rc : len;
> +}
> +
> +static const struct file_operations scom_fops = {
> + .owner = THIS_MODULE,
> + .llseek = scom_llseek,
> + .read = scom_read,
> + .write = scom_write,
> +};
> +
> +static int scom_probe(struct device *dev)
> +{
> + struct fsi_device *fsi_dev = to_fsi_dev(dev);
> + struct scom_device *scom = NULL;
> +
> + scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
> + if (!scom)
> + return -ENOMEM;
> +
> + snprintf(scom->name, sizeof(scom->name),
> + "scom%d", atomic_inc_return(&scom_idx));
> + scom->fsi_dev = fsi_dev;
> + scom->mdev.minor = MISC_DYNAMIC_MINOR;
> + scom->mdev.fops = &scom_fops;
> + scom->mdev.name = scom->name;
> + scom->mdev.parent = dev;
> + list_add(&scom->link, &scom_devices);
> +
> + return misc_register(&scom->mdev);
> +}
> +
> +static struct fsi_device_id scom_ids[] = {
> + {
> + .engine_type = FSI_ENGID_SCOM,
> + .version = FSI_VERSION_ANY,
> + },
> + { 0 }
> +};
> +
> +static struct fsi_driver scom_drv = {
> + .id_table = scom_ids,
> + .drv = {
> + .name = "scom",
> + .bus = &fsi_bus_type,
> + .probe = scom_probe,
> + }
> +};
> +
> +static int scom_init(void)
> +{
> + INIT_LIST_HEAD(&scom_devices);
> + return fsi_driver_register(&scom_drv);
> +}
> +
> +static void scom_exit(void)
> +{
> + struct list_head *pos;
> + struct scom_device *scom = NULL;
> +
> + list_for_each(pos, &scom_devices) {
> + scom = list_entry(pos, struct scom_device, link);
> + misc_deregister(&scom->mdev);
> + devm_kfree(&scom->fsi_dev->dev, scom);
> + }
> + fsi_driver_unregister(&scom_drv);
> +}
> +
> +module_init(scom_init);
> +module_exit(scom_exit);
> +MODULE_LICENSE("GPL");
>
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