[PATCH linux dev-4.7 2/3] drivers: fsi: sbefifo: Add OCC driver
Eddie James
eajames at linux.vnet.ibm.com
Wed Apr 19 07:07:13 AEST 2017
From: "Edward A. James" <eajames at us.ibm.com>
Add a driver to control communications with the OCC on the POWER9. The
driver communicates with OCC SRAM using the FSI SBEFIFO driver.
The format of the communication is a command followed by response. The
sequence must be done atomically. The driver performs these operations
asynchronously, such that a write operation starts the command, and a
read will gather the response data.
Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
drivers/fsi/Kconfig | 10 +
drivers/fsi/Makefile | 1 +
drivers/fsi/occfifo.c | 649 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 660 insertions(+)
create mode 100644 drivers/fsi/occfifo.c
diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
index 087f239..8dbe5d9 100644
--- a/drivers/fsi/Kconfig
+++ b/drivers/fsi/Kconfig
@@ -24,6 +24,16 @@ config FSI_SBEFIFO
---help---
This option enables an FSI based SBEFIFO device driver.
+if FSI_SBEFIFO
+
+config OCCFIFO
+ tristate "OCC SBEFIFO client device driver"
+ depends on FSI_SBEFIFO
+ ---help---
+ This option enables an FSI based OCC driver using the SBEFIFO.
+
+endif
+
config FSI_SCOM
tristate "SCOM FSI client device driver"
depends on FSI
diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
index edd84b2..eddaf79 100644
--- a/drivers/fsi/Makefile
+++ b/drivers/fsi/Makefile
@@ -2,5 +2,6 @@
obj-$(CONFIG_FSI) += fsi-core.o
obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
obj-$(CONFIG_FSI_SBEFIFO) += fsi-sbefifo.o
+obj-$(CONFIG_OCCFIFO) += occfifo.o
obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
obj-$(CONFIG_FSI_I2C) += i2c/
diff --git a/drivers/fsi/occfifo.c b/drivers/fsi/occfifo.c
new file mode 100644
index 0000000..c1a3351
--- /dev/null
+++ b/drivers/fsi/occfifo.c
@@ -0,0 +1,649 @@
+/*
+ * 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 occfifo {
+ struct sbefifo_drv_ref ref;
+ struct sbefifo *sbefifo;
+ char name[32];
+ struct miscdevice mdev;
+ struct list_head xfrs;
+ spinlock_t list_lock;
+ spinlock_t occ_lock;
+ struct work_struct work;
+};
+
+#define to_occfifo(x) container_of((x), struct occfifo, mdev)
+
+struct occ_command {
+ u8 seq_no;
+ u8 cmd_type;
+ u16 data_length;
+ u8 data[OCC_CMD_DATA_BYTES];
+ u16 checksum;
+};
+
+struct occ_response {
+ u8 seq_no;
+ u8 cmd_type;
+ u8 return_status;
+ u16 data_length;
+ u8 data[OCC_RESP_DATA_BYTES];
+ u16 checksum;
+};
+
+struct occfifo_xfr;
+
+enum {
+ CLIENT_NONBLOCKING,
+};
+
+struct occfifo_client {
+ struct occfifo *occfifo;
+ struct occfifo_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 occfifo_xfr {
+ struct list_head link;
+ struct occfifo_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 *occfifo_wq;
+
+static void occfifo_enqueue_xfr(struct occfifo_xfr *xfr)
+{
+ int empty;
+ struct occfifo *occfifo = xfr->client->occfifo;
+
+ spin_lock_irq(&occfifo->list_lock);
+ empty = list_empty(&occfifo->xfrs);
+ list_add_tail(&xfr->link, &occfifo->xfrs);
+ spin_unlock(&occfifo->list_lock);
+
+ if (empty)
+ queue_work(occfifo_wq, &occfifo->work);
+}
+
+static int occfifo_open(struct inode *inode, struct file *file)
+{
+ struct occfifo_client *client;
+ struct miscdevice *mdev = file->private_data;
+ struct occfifo *occfifo = to_occfifo(mdev);
+
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
+ if (!client)
+ return -ENOMEM;
+
+ client->occfifo = occfifo;
+ 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 occfifo_read(struct file *file, char __user *buf, size_t len,
+ loff_t *offset)
+{
+ int rc;
+ size_t bytes;
+ struct occfifo_xfr *xfr;
+ struct occfifo_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 occfifo_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *offset)
+{
+ int rc;
+ struct occfifo_xfr *xfr;
+ struct occfifo_client *client = file->private_data;
+
+ if (!access_ok(VERIFY_READ, buf, len))
+ return -EFAULT;
+
+ if (len > OCC_SRAM_BYTES)
+ 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;
+ }
+
+ if (copy_from_user(xfr->buf, buf, len)) {
+ kfree(xfr);
+ rc = -EFAULT;
+ goto done;
+ }
+
+ xfr->client = client;
+ xfr->cmd_data_length = len;
+ client->xfr = xfr;
+ client->read_offset = 0;
+
+ occfifo_enqueue_xfr(xfr);
+
+ rc = len;
+
+done:
+ spin_unlock(&client->lock);
+ return rc;
+}
+
+static int occfifo_release(struct inode *inode, struct file *file)
+{
+ struct occfifo_xfr *xfr;
+ struct occfifo_client *client = file->private_data;
+ struct occfifo *occfifo = client->occfifo;
+
+ spin_lock_irq(&client->lock);
+ xfr = client->xfr;
+ if (!xfr) {
+ spin_unlock(&client->lock);
+ kfree(client);
+ return 0;
+ }
+
+ spin_lock_irq(&occfifo->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(&occfifo->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(&occfifo->list_lock);
+ spin_unlock(&client->lock);
+ return 0;
+}
+
+static const struct file_operations occfifo_fops = {
+ .owner = THIS_MODULE,
+ .open = occfifo_open,
+ .read = occfifo_read,
+ .write = occfifo_write,
+ .release = occfifo_release,
+};
+
+static int occfifo_getscom(struct sbefifo *sbefifo, u32 address, u8 *data)
+{
+ int rc;
+ u32 buf[4];
+ struct sbefifo_client *client;
+ const size_t len = sizeof(buf);
+
+ buf[0] = 0x4;
+ buf[1] = 0xa201;
+ buf[2] = 0;
+ buf[3] = 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 = -EIO;
+ goto done;
+ }
+
+ rc = sbefifo_drv_read(client, (char *)buf, len);
+ if (rc < 0)
+ goto done;
+ else if (rc != len) {
+ rc = -EIO;
+ goto done;
+ }
+
+ rc = 0;
+
+ memcpy(data, buf, sizeof(u64));
+
+done:
+ sbefifo_drv_release(client);
+ return rc;
+}
+
+static int occfifo_putscom(struct sbefifo *sbefifo, u32 address, u8 *data)
+{
+ int rc;
+ u32 buf[6];
+ struct sbefifo_client *client;
+ const size_t len = sizeof(buf);
+
+ buf[0] = 0x6;
+ buf[1] = 0xa202;
+ buf[2] = 0;
+ buf[3] = 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 = -EIO;
+ goto done;
+ }
+
+ rc = sbefifo_drv_read(client, (char *)buf, sizeof(u32) * 4);
+ if (rc < 0) {
+ rc = 0;
+ goto done;
+ } else if (rc != sizeof(u32) * 4) {
+ rc = -EIO;
+ goto done;
+ }
+
+ rc = 0;
+
+done:
+ sbefifo_drv_release(client);
+ return rc;
+}
+
+static int occfifo_putscom_u32(struct sbefifo *sbefifo, u32 address, u32 data0,
+ u32 data1)
+{
+ u8 buf[8];
+
+ memcpy(buf, &data0, 4);
+ memcpy(buf + 4, &data1, 4);
+
+ return occfifo_putscom(sbefifo, address, buf);
+}
+
+static void occfifo_worker(struct work_struct *work)
+{
+ int i, empty, canceled, waiting, rc;
+ u16 resp_data_length;
+ struct occfifo *occfifo = container_of(work, struct occfifo, work);
+ struct sbefifo *sbefifo = occfifo->sbefifo;
+ struct occfifo_client *client;
+ struct occfifo_xfr *xfr;
+ struct occ_response *resp;
+
+again:
+ spin_lock_irq(&occfifo->list_lock);
+ xfr = list_first_entry(&occfifo->xfrs, struct occfifo_xfr, link);
+ if (!xfr) {
+ spin_unlock(&occfifo->list_lock);
+ return;
+ }
+
+ set_bit(XFR_IN_PROGRESS, &xfr->flags);
+ spin_unlock(&occfifo->list_lock);
+
+ resp = (struct occ_response *)xfr->buf;
+
+ spin_lock_irq(&occfifo->occ_lock);
+
+ /* set stream mode enabled */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D053, 0x08000000, 0);
+ if (rc)
+ goto done;
+
+ /* set stream mode to linear */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D052, 0x04000000, 0);
+ if (rc)
+ goto done;
+
+ /* set address reg to occ sram command buffer */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D050, 0xFFFBE000, 0);
+ if (rc)
+ goto done;
+
+ /* write cmd data */
+ for (i = 0; i < xfr->cmd_data_length; i += 8) {
+ rc = occfifo_putscom(sbefifo, 0x6D055, &xfr->buf[i]);
+ if (rc)
+ goto done;
+ }
+
+ /* set stream mode enabled and stream mode to circular */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D033, 0x0C000000, 0);
+ if (rc)
+ goto done;
+
+ /* trigger attention */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D035, 0x20010000, 0);
+ if (rc)
+ goto done;
+
+ /* set address reg to occ sram response buffer */
+ rc = occfifo_putscom_u32(sbefifo, 0x6D050, 0xFFFBF000, 0);
+ if (rc)
+ goto done;
+
+ rc = occfifo_getscom(sbefifo, 0x6D055, xfr->buf);
+ if (rc)
+ goto done;
+
+ xfr->resp_data_length += 8;
+
+ resp_data_length = be16_to_cpu(get_unaligned(&resp->data_length));
+ if (resp_data_length > OCC_RESP_DATA_BYTES) {
+ rc = -EFAULT;
+ 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 = occfifo_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(&occfifo->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(&occfifo->list_lock);
+ clear_bit(XFR_IN_PROGRESS, &xfr->flags);
+ list_del(&xfr->link);
+ empty = list_empty(&occfifo->xfrs);
+ canceled = test_bit(XFR_CANCELED, &xfr->flags);
+ spin_unlock(&occfifo->list_lock);
+
+ if (waiting)
+ wake_up_interruptible(&client->wait);
+ else if (canceled) {
+ kfree(xfr);
+ kfree(xfr->client);
+ }
+
+ if (!empty)
+ goto again;
+}
+
+void occfifo_notify(struct sbefifo_drv_ref *ref)
+{
+ struct occfifo *occfifo = container_of(ref, struct occfifo, ref);
+
+ /* TODO: find better solution? this does seem to work if we lose
+ * the sbefifo in the middle of a transfer
+ */
+ occfifo->sbefifo = NULL;
+}
+
+static int occfifo_probe(struct platform_device *pdev)
+{
+ int rc;
+ struct occfifo *occfifo;
+ struct device_node *bus;
+ struct device *dev = &pdev->dev;
+ struct device_node *node = dev->of_node;
+
+ occfifo = devm_kzalloc(dev, sizeof(*occfifo), GFP_KERNEL);
+ if (!occfifo)
+ return -ENOMEM;
+
+ bus = of_parse_phandle(node, "bus", 0);
+ if (!bus) {
+ dev_err(dev, "failed to get dts phandle\n");
+ return -ENODEV;
+ }
+
+ occfifo->ref.notify = occfifo_notify;
+ occfifo->sbefifo = sbefifo_drv_reference(bus, &occfifo->ref);
+ if (!occfifo->sbefifo) {
+ dev_err(dev, "failed to get sbefifo reference\n");
+ rc = -ENODEV;
+ goto done;
+ }
+
+ INIT_LIST_HEAD(&occfifo->xfrs);
+ spin_lock_init(&occfifo->list_lock);
+ spin_lock_init(&occfifo->occ_lock);
+ INIT_WORK(&occfifo->work, occfifo_worker);
+
+ snprintf(occfifo->name, sizeof(occfifo->name), "occfifo%d",
+ sbefifo_drv_get_idx(occfifo->sbefifo));
+
+ occfifo->mdev.fops = &occfifo_fops;
+ occfifo->mdev.minor = MISC_DYNAMIC_MINOR;
+ occfifo->mdev.name = occfifo->name;
+ occfifo->mdev.parent = dev;
+
+ rc = misc_register(&occfifo->mdev);
+ if (rc) {
+ dev_err(dev, "failed to register miscdevice\n");
+ goto done;
+ }
+
+ platform_set_drvdata(pdev, occfifo);
+
+done:
+ of_node_put(bus);
+ return rc;
+}
+
+static int occfifo_remove(struct platform_device *pdev)
+{
+ struct occfifo_xfr *xfr, *tmp;
+ struct occfifo *occfifo = platform_get_drvdata(pdev);
+ struct occfifo_client *client;
+
+ misc_deregister(&occfifo->mdev);
+
+ spin_lock_irq(&occfifo->list_lock);
+ list_for_each_entry_safe(xfr, tmp, &occfifo->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(&occfifo->list_lock);
+
+ flush_work(&occfifo->work);
+ list_del(&occfifo->ref.link);
+
+ return 0;
+}
+
+static const struct of_device_id occfifo_match[] = {
+ { .compatible = "ibm,occfifo" },
+ { },
+};
+
+static struct platform_driver occfifo_driver = {
+ .driver = {
+ .name = "occfifo",
+ .of_match_table = occfifo_match,
+ },
+ .probe = occfifo_probe,
+ .remove = occfifo_remove,
+};
+
+static int occfifo_init(void)
+{
+ occfifo_wq = create_singlethread_workqueue("occfifo");
+ if (!occfifo_wq)
+ return -ENOMEM;
+
+ return platform_driver_register(&occfifo_driver);
+}
+
+static void occfifo_exit(void)
+{
+ destroy_workqueue(occfifo_wq);
+
+ platform_driver_unregister(&occfifo_driver);
+}
+
+module_init(occfifo_init);
+module_exit(occfifo_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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