[PATCH linux dev-4.10 v2 2/2] drivers: fsi: sbefifo: Add OCC driver
Eddie James
eajames at linux.vnet.ibm.com
Thu May 25 04:37:35 AEST 2017
From: "Edward A. James" <eajames at us.ibm.com>
This driver provides an atomic communications channel between the OCC on
the POWER9 processor and a service processor (a BMC). The driver is
dependent on the FSI SBEIFO driver to get hardware access to the OCC
SRAM.
The format of the communication is a command followed by a response.
Since the command and response must be performed atomically, the driver
will perform this operations asynchronously. In this way, a write
operation starts the command, and a read will gather the response data
once it is complete.
Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
drivers/fsi/Kconfig | 9 +
drivers/fsi/Makefile | 1 +
drivers/fsi/occ.c | 640 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 650 insertions(+)
create mode 100644 drivers/fsi/occ.c
diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
index 39527fa..be1b509 100644
--- a/drivers/fsi/Kconfig
+++ b/drivers/fsi/Kconfig
@@ -36,6 +36,15 @@ config FSI_SBEFIFO
---help---
This option enables an FSI based SBEFIFO device driver.
+if FSI_SBEFIFO
+
+config SBEFIFO_OCC
+ tristate "OCC SBEFIFO client device driver"
+ ---help---
+ This option enables an SBEFIFO based OCC device driver.
+
+endif
+
endif
endmenu
diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
index 851182e..9d460d3 100644
--- a/drivers/fsi/Makefile
+++ b/drivers/fsi/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
obj-$(CONFIG_FSI_SBEFIFO) += fsi-sbefifo.o
+obj-$(CONFIG_SBEFIO_OCC) += occ.o
diff --git a/drivers/fsi/occ.c b/drivers/fsi/occ.c
new file mode 100644
index 0000000..630188c
--- /dev/null
+++ b/drivers/fsi/occ.c
@@ -0,0 +1,640 @@
+/*
+ * Copyright 2017 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fsi-sbefifo.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+
+#define OCC_SRAM_BYTES 4096
+#define OCC_CMD_DATA_BYTES 4090
+#define OCC_RESP_DATA_BYTES 4089
+
+struct occ {
+ struct device *sbefifo;
+ char name[32];
+ int idx;
+ struct miscdevice mdev;
+ struct list_head xfrs;
+ spinlock_t list_lock;
+ spinlock_t occ_lock;
+ struct work_struct work;
+};
+
+#define to_occ(x) container_of((x), struct occ, mdev)
+
+struct occ_command {
+ u8 seq_no;
+ u8 cmd_type;
+ u16 data_length;
+ u8 data[OCC_CMD_DATA_BYTES];
+ u16 checksum;
+} __packed;
+
+struct occ_response {
+ u8 seq_no;
+ u8 cmd_type;
+ u8 return_status;
+ u16 data_length;
+ u8 data[OCC_RESP_DATA_BYTES];
+ u16 checksum;
+} __packed;
+
+struct occ_xfr;
+
+enum {
+ CLIENT_NONBLOCKING,
+};
+
+struct occ_client {
+ struct occ *occ;
+ struct occ_xfr *xfr;
+ spinlock_t lock;
+ wait_queue_head_t wait;
+ size_t read_offset;
+ unsigned long flags;
+};
+
+enum {
+ XFR_IN_PROGRESS,
+ XFR_COMPLETE,
+ XFR_CANCELED,
+ XFR_WAITING,
+};
+
+struct occ_xfr {
+ struct list_head link;
+ struct occ_client *client;
+ int rc;
+ u8 buf[OCC_SRAM_BYTES];
+ size_t cmd_data_length;
+ size_t resp_data_length;
+ unsigned long flags;
+};
+
+static struct workqueue_struct *occ_wq;
+
+static DEFINE_IDA(occ_ida);
+
+static void occ_enqueue_xfr(struct occ_xfr *xfr)
+{
+ int empty;
+ struct occ *occ = xfr->client->occ;
+
+ spin_lock_irq(&occ->list_lock);
+ empty = list_empty(&occ->xfrs);
+ list_add_tail(&xfr->link, &occ->xfrs);
+ spin_unlock(&occ->list_lock);
+
+ if (empty)
+ queue_work(occ_wq, &occ->work);
+}
+
+static int occ_open(struct inode *inode, struct file *file)
+{
+ struct occ_client *client;
+ struct miscdevice *mdev = file->private_data;
+ struct occ *occ = to_occ(mdev);
+
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
+ if (!client)
+ return -ENOMEM;
+
+ client->occ = occ;
+ spin_lock_init(&client->lock);
+ init_waitqueue_head(&client->wait);
+
+ if (file->f_flags & O_NONBLOCK)
+ set_bit(CLIENT_NONBLOCKING, &client->flags);
+
+ file->private_data = client;
+
+ return 0;
+}
+
+static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
+ loff_t *offset)
+{
+ int rc;
+ size_t bytes;
+ struct occ_xfr *xfr;
+ struct occ_client *client = file->private_data;
+
+ if (!access_ok(VERIFY_WRITE, buf, len))
+ return -EFAULT;
+
+ if (len > OCC_SRAM_BYTES)
+ return -EINVAL;
+
+ spin_lock_irq(&client->lock);
+ if (!client->xfr) {
+ /* we just finished reading all data, return 0 */
+ if (client->read_offset) {
+ rc = 0;
+ client->read_offset = 0;
+ } else
+ rc = -ENOMSG;
+
+ goto done;
+ }
+
+ xfr = client->xfr;
+
+ if (!test_bit(XFR_COMPLETE, &xfr->flags)) {
+ if (client->flags & CLIENT_NONBLOCKING) {
+ rc = -ERESTARTSYS;
+ goto done;
+ }
+
+ set_bit(XFR_WAITING, &xfr->flags);
+ spin_unlock(&client->lock);
+
+ rc = wait_event_interruptible(client->wait,
+ test_bit(XFR_COMPLETE, &xfr->flags) ||
+ test_bit(XFR_CANCELED, &xfr->flags));
+
+ spin_lock_irq(&client->lock);
+ if (test_bit(XFR_CANCELED, &xfr->flags)) {
+ kfree(xfr);
+ spin_unlock(&client->lock);
+ kfree(client);
+ return -EBADFD;
+ }
+
+ clear_bit(XFR_WAITING, &xfr->flags);
+ if (!test_bit(XFR_COMPLETE, &xfr->flags)) {
+ rc = -EINTR;
+ goto done;
+ }
+ }
+
+ if (xfr->rc) {
+ rc = xfr->rc;
+ goto done;
+ }
+
+ bytes = min(len, xfr->resp_data_length - client->read_offset);
+ if (copy_to_user(buf, &xfr->buf[client->read_offset], bytes)) {
+ rc = -EFAULT;
+ goto done;
+ }
+
+ client->read_offset += bytes;
+
+ /* xfr done */
+ if (client->read_offset == xfr->resp_data_length) {
+ kfree(xfr);
+ client->xfr = NULL;
+ }
+
+ rc = bytes;
+
+done:
+ spin_unlock(&client->lock);
+ return rc;
+}
+
+static ssize_t occ_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *offset)
+{
+ int rc;
+ u16 data_length, checksum = 0;
+ struct occ_xfr *xfr;
+ struct occ_client *client = file->private_data;
+
+ if (!access_ok(VERIFY_READ, buf, len))
+ return -EFAULT;
+
+ if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
+ return -EINVAL;
+
+ spin_lock_irq(&client->lock);
+ if (client->xfr) {
+ rc = -EDEADLK;
+ goto done;
+ }
+
+ xfr = kzalloc(sizeof(*xfr), GFP_KERNEL);
+ if (!xfr) {
+ rc = -ENOMEM;
+ goto done;
+ }
+
+ xfr->buf[0] = 1;
+
+ if (copy_from_user(&xfr->buf[1], buf, len)) {
+ kfree(xfr);
+ rc = -EFAULT;
+ goto done;
+ }
+
+ data_length = (xfr->buf[2] << 8) + xfr->buf[3];
+ if (data_length > OCC_CMD_DATA_BYTES) {
+ kfree(xfr);
+ rc = -EINVAL;
+ goto done;
+ }
+
+ for (i = 0; i < data_length + 4; ++i)
+ checksum += xfr->buf[i];
+
+ xfr->buf[data_length + 4] = checksum >> 8;
+ xfr->buf[data_length + 5] = checksum & 0xFF;
+
+ xfr->client = client;
+ xfr->cmd_data_length = data_length + 6;
+ client->xfr = xfr;
+ client->read_offset = 0;
+
+ occ_enqueue_xfr(xfr);
+
+ rc = len;
+
+done:
+ spin_unlock(&client->lock);
+ return rc;
+}
+
+static int occ_release(struct inode *inode, struct file *file)
+{
+ struct occ_xfr *xfr;
+ struct occ_client *client = file->private_data;
+ struct occ *occ = client->occ;
+
+ spin_lock_irq(&client->lock);
+ xfr = client->xfr;
+ if (!xfr) {
+ spin_unlock(&client->lock);
+ kfree(client);
+ return 0;
+ }
+
+ spin_lock_irq(&occ->list_lock);
+ set_bit(XFR_CANCELED, &xfr->flags);
+ if (!test_bit(XFR_IN_PROGRESS, &xfr->flags)) {
+ /* already deleted from list if complete */
+ if (!test_bit(XFR_COMPLETE, &xfr->flags))
+ list_del(&xfr->link);
+
+ spin_unlock(&occ->list_lock);
+
+ if (test_bit(XFR_WAITING, &xfr->flags)) {
+ /* blocking read; let reader clean up */
+ wake_up_interruptible(&client->wait);
+ spin_unlock(&client->lock);
+ return 0;
+ }
+
+ kfree(xfr);
+ spin_unlock(&client->lock);
+ kfree(client);
+ return 0;
+ }
+
+ /* operation is in progress; let worker clean up*/
+ spin_unlock(&occ->list_lock);
+ spin_unlock(&client->lock);
+ return 0;
+}
+
+static const struct file_operations occ_fops = {
+ .owner = THIS_MODULE,
+ .open = occ_open,
+ .read = occ_read,
+ .write = occ_write,
+ .release = occ_release,
+};
+
+static int occ_getscom(struct device *sbefifo, u32 address, u8 *data)
+{
+ int rc;
+ u32 buf[4];
+ struct sbefifo_client *client;
+ const size_t len = sizeof(buf);
+
+ buf[0] = cpu_to_be32(0x4);
+ buf[1] = cpu_to_be32(0xa201);
+ buf[2] = 0;
+ buf[3] = cpu_to_be32(address);
+
+ client = sbefifo_drv_open(sbefifo, 0);
+ if (!client)
+ return -ENODEV;
+
+ rc = sbefifo_drv_write(client, (const char *)buf, len);
+ if (rc < 0)
+ goto done;
+ else if (rc != len) {
+ rc = -EMSGSIZE;
+ goto done;
+ }
+
+ rc = sbefifo_drv_read(client, (char *)buf, len);
+ if (rc < 0)
+ goto done;
+ else if (rc != len) {
+ rc = -EMSGSIZE;
+ goto done;
+ }
+
+ /* check for good response */
+ if ((be32_to_cpu(buf[2]) >> 16) != 0xC0DE) {
+ rc = -EFAULT;
+ goto done;
+ }
+
+ rc = 0;
+
+ memcpy(data, buf, sizeof(u64));
+
+done:
+ sbefifo_drv_release(client);
+ return rc;
+}
+
+static int occ_putscom(struct device *sbefifo, u32 address, u8 *data)
+{
+ int rc;
+ u32 buf[6];
+ struct sbefifo_client *client;
+ const size_t len = sizeof(buf);
+
+ buf[0] = cpu_to_be32(0x6);
+ buf[1] = cpu_to_be32(0xa202);
+ buf[2] = 0;
+ buf[3] = cpu_to_be32(address);
+ memcpy(&buf[4], data, sizeof(u64));
+
+ client = sbefifo_drv_open(sbefifo, 0);
+ if (!client)
+ return -ENODEV;
+
+ rc = sbefifo_drv_write(client, (const char *)buf, len);
+ if (rc < 0)
+ goto done;
+ else if (rc != len) {
+ rc = -EMSGSIZE;
+ goto done;
+ }
+
+ rc = 0;
+
+ /* ignore response */
+ sbefifo_drv_read(client, (char *)buf, len);
+
+done:
+ sbefifo_drv_release(client);
+ return rc;
+}
+
+static int occ_putscom_u32(struct device *sbefifo, u32 address, u32 data0,
+ u32 data1)
+{
+ u8 buf[8];
+ u32 raw_data0 = cpu_to_be32(data0), raw_data1 = cpu_to_be32(data1);
+
+ memcpy(buf, &raw_data0, 4);
+ memcpy(buf + 4, &raw_data1, 4);
+
+ return occ_putscom(sbefifo, address, buf);
+}
+
+static void occ_worker(struct work_struct *work)
+{
+ int i, empty, canceled, waiting, rc;
+ u16 resp_data_length;
+ struct occ *occ = container_of(work, struct occ, work);
+ struct device *sbefifo = occ->sbefifo;
+ struct occ_client *client;
+ struct occ_xfr *xfr;
+ struct occ_response *resp;
+
+again:
+ spin_lock_irq(&occ->list_lock);
+ xfr = list_first_entry(&occ->xfrs, struct occ_xfr, link);
+ if (!xfr) {
+ spin_unlock(&occ->list_lock);
+ return;
+ }
+
+ set_bit(XFR_IN_PROGRESS, &xfr->flags);
+ spin_unlock(&occ->list_lock);
+
+ resp = (struct occ_response *)xfr->buf;
+
+ spin_lock_irq(&occ->occ_lock);
+
+ /* set address reg to occ sram command buffer */
+ rc = occ_putscom_u32(sbefifo, 0x6D050, 0xFFFBE000, 0);
+ if (rc)
+ goto done;
+
+ /* write cmd data */
+ for (i = 0; i < xfr->cmd_data_length; i += 8) {
+ rc = occ_putscom(sbefifo, 0x6D055, &xfr->buf[i]);
+ if (rc)
+ goto done;
+ }
+
+ /* trigger attention */
+ rc = occ_putscom_u32(sbefifo, 0x6D035, 0x20010000, 0);
+ if (rc)
+ goto done;
+
+ /* set address reg to occ sram response buffer */
+ rc = occ_putscom_u32(sbefifo, 0x6D050, 0xFFFBF000, 0);
+ if (rc)
+ goto done;
+
+ rc = occ_getscom(sbefifo, 0x6D055, xfr->buf);
+ if (rc)
+ goto done;
+
+ xfr->resp_data_length += 8;
+
+ resp_data_length = (xfr->buf[3] << 8) + xfr->buf[4];
+ if (resp_data_length > OCC_RESP_DATA_BYTES) {
+ rc = -EDOM;
+ goto done;
+ }
+
+ /* already read 3 bytes of resp data, but also need 2 bytes chksum */
+ for (i = 8; i < resp_data_length + 7; i += 8) {
+ rc = occ_getscom(sbefifo, 0x6D055, &xfr->buf[i]);
+ if (rc)
+ goto done;
+
+ xfr->resp_data_length += 8;
+ }
+
+ /* no errors, got all data */
+ xfr->resp_data_length = resp_data_length + 7;
+
+done:
+ spin_unlock(&occ->occ_lock);
+
+ xfr->rc = rc;
+ client = xfr->client;
+
+ /* lock client to prevent race with read() */
+ spin_lock_irq(&client->lock);
+ set_bit(XFR_COMPLETE, &xfr->flags);
+ waiting = test_bit(XFR_WAITING, &xfr->flags);
+ spin_unlock(&client->lock);
+
+ spin_lock_irq(&occ->list_lock);
+ clear_bit(XFR_IN_PROGRESS, &xfr->flags);
+ list_del(&xfr->link);
+ empty = list_empty(&occ->xfrs);
+ canceled = test_bit(XFR_CANCELED, &xfr->flags);
+ spin_unlock(&occ->list_lock);
+
+ if (waiting)
+ wake_up_interruptible(&client->wait);
+ else if (canceled) {
+ kfree(xfr);
+ kfree(xfr->client);
+ }
+
+ if (!empty)
+ goto again;
+}
+
+static int occ_probe(struct platform_device *pdev)
+{
+ int rc;
+ u32 reg;
+ struct occ *occ;
+ struct device *dev = &pdev->dev;
+
+ dev_info(dev, "Found occ device\n");
+ occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL);
+ if (!occ)
+ return -ENOMEM;
+
+ occ->sbefifo = dev->parent;
+ INIT_LIST_HEAD(&occ->xfrs);
+ spin_lock_init(&occ->list_lock);
+ spin_lock_init(&occ->occ_lock);
+ INIT_WORK(&occ->work, occ_worker);
+
+ if (dev->of_node) {
+ rc = of_property_read_u32(dev->of_node, "reg", ®);
+ if (!rc) {
+ /* make sure we don't have a duplicate from dts */
+ occ->idx = ida_simple_get(&occ_ida, reg, reg + 1,
+ GFP_KERNEL);
+ if (occ->idx < 0)
+ occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
+ GFP_KERNEL);
+ } else
+ occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
+ GFP_KERNEL);
+ } else
+ occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
+
+ snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
+ occ->mdev.fops = &occ_fops;
+ occ->mdev.minor = MISC_DYNAMIC_MINOR;
+ occ->mdev.name = occ->name;
+ occ->mdev.parent = dev;
+
+ rc = misc_register(&occ->mdev);
+ if (rc) {
+ dev_err(dev, "failed to register miscdevice\n");
+ return rc;
+ }
+
+ platform_set_drvdata(pdev, occ);
+
+ return 0;
+}
+
+static int occ_remove(struct platform_device *pdev)
+{
+ struct occ_xfr *xfr, *tmp;
+ struct occ *occ = platform_get_drvdata(pdev);
+ struct occ_client *client;
+
+ misc_deregister(&occ->mdev);
+
+ spin_lock_irq(&occ->list_lock);
+ list_for_each_entry_safe(xfr, tmp, &occ->xfrs, link) {
+ client = xfr->client;
+ set_bit(XFR_CANCELED, &xfr->flags);
+
+ if (!test_bit(XFR_IN_PROGRESS, &xfr->flags)) {
+ list_del(&xfr->link);
+
+ spin_lock_irq(&client->lock);
+ if (test_bit(XFR_WAITING, &xfr->flags)) {
+ wake_up_interruptible(&client->wait);
+ spin_unlock(&client->lock);
+ } else {
+ kfree(xfr);
+ spin_unlock(&client->lock);
+ kfree(client);
+ }
+ }
+ }
+ spin_unlock(&occ->list_lock);
+
+ flush_work(&occ->work);
+
+ ida_simple_remove(&occ_ida, occ->idx);
+
+ return 0;
+}
+
+static const struct of_device_id occ_match[] = {
+ { .compatible = "ibm,p9-occ" },
+ { },
+};
+
+static struct platform_driver occ_driver = {
+ .driver = {
+ .name = "occ",
+ .of_match_table = occ_match,
+ },
+ .probe = occ_probe,
+ .remove = occ_remove,
+};
+
+static int occ_init(void)
+{
+ occ_wq = create_singlethread_workqueue("occ");
+ if (!occ_wq)
+ return -ENOMEM;
+
+ return platform_driver_register(&occ_driver);
+}
+
+static void occ_exit(void)
+{
+ destroy_workqueue(occ_wq);
+
+ platform_driver_unregister(&occ_driver);
+}
+
+module_init(occ_init);
+module_exit(occ_exit);
+
+MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
+MODULE_DESCRIPTION("BMC P9 OCC driver");
+MODULE_LICENSE("GPL");
--
1.8.3.1
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