[PATCH linux v6 18/18] drivers/fsi: Add SCOM FSI client device driver
Christopher Bostic
christopher.lee.bostic at gmail.com
Tue Nov 15 04:13:55 AEDT 2016
On Sun, Nov 13, 2016 at 5:44 PM, Alistair Popple <alistair at popple.id.au> wrote:
> 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
>
Hi Alistair,
No there isn't a driver like you describe in the set as it is now. I
agree that would be important to have for general bringup debug.
Once this set is accepted I'll add that.
Thanks
> 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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