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Message-Id: <20180724050519.31920-5-benh@kernel.crashing.org>
Date: Tue, 24 Jul 2018 15:05:18 +1000
From: Benjamin Herrenschmidt <benh@...nel.crashing.org>
To: openbmc@...ts.ozlabs.org
Cc: Joel Stanley <joel@....id.au>, linux-aspeed@...ts.ozlabs.org,
Andrew Jeffery <andrew@...id.au>,
Eddie James <eajames@...ux.vnet.ibm.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>
Subject: [PATCH 4/5] fsi: Add cfam char devices
This aims to deprecate the "raw" sysfs file used for directly
accessing the CFAM and instead use a char device like the
other sub drivers.
Since it reworks the slave creation code and adds a cfam device
type, we also use the opportunity to convert the attributes
to attribute groups and add a couple more.
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
---
drivers/fsi/fsi-core.c | 264 +++++++++++++++++++++++++++++++++--------
1 file changed, 213 insertions(+), 51 deletions(-)
diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index faa1760a5a40..dea5bd48acc5 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -11,6 +11,11 @@
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
+ *
+ * TODO:
+ * - Rework topology
+ * - s/chip_id/chip_loc
+ * - s/cfam/chip (cfam_id -> chip_id etc...)
*/
#include <linux/crc4.h>
@@ -21,6 +26,9 @@
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/bitops.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
#include "fsi-master.h"
@@ -78,8 +86,11 @@ static DEFINE_IDA(master_ida);
struct fsi_slave {
struct device dev;
struct fsi_master *master;
- int id;
- int link;
+ struct cdev cdev;
+ int cdev_idx;
+ int id; /* FSI address */
+ int link; /* FSI link# */
+ u32 cfam_id;
int chip_id;
uint32_t size; /* size of slave address space */
u8 t_send_delay;
@@ -607,29 +618,6 @@ static const struct bin_attribute fsi_slave_raw_attr = {
.write = fsi_slave_sysfs_raw_write,
};
-static ssize_t fsi_slave_sysfs_term_write(struct file *file,
- struct kobject *kobj, struct bin_attribute *attr,
- char *buf, loff_t off, size_t count)
-{
- struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
- struct fsi_master *master = slave->master;
-
- if (!master->term)
- return -ENODEV;
-
- master->term(master, slave->link, slave->id);
- return count;
-}
-
-static const struct bin_attribute fsi_slave_term_attr = {
- .attr = {
- .name = "term",
- .mode = 0200,
- },
- .size = 0,
- .write = fsi_slave_sysfs_term_write,
-};
-
static void fsi_slave_release(struct device *dev)
{
struct fsi_slave *slave = to_fsi_slave(dev);
@@ -682,6 +670,127 @@ static struct device_node *fsi_slave_find_of_node(struct fsi_master *master,
return NULL;
}
+static ssize_t cfam_read(struct file *filep, char __user *buf, size_t count,
+ loff_t *offset)
+{
+ struct fsi_slave *slave = filep->private_data;
+ size_t total_len, read_len;
+ loff_t off = *offset;
+ ssize_t rc;
+
+ if (off < 0)
+ return -EINVAL;
+
+ if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
+ return -EINVAL;
+
+ for (total_len = 0; total_len < count; total_len += read_len) {
+ __be32 data;
+
+ read_len = min_t(size_t, count, 4);
+ read_len -= off & 0x3;
+
+ rc = fsi_slave_read(slave, off, &data, read_len);
+ if (rc)
+ goto fail;
+ rc = copy_to_user(buf + total_len, &data, read_len);
+ if (rc) {
+ rc = -EFAULT;
+ goto fail;
+ }
+ off += read_len;
+ }
+ rc = count;
+ fail:
+ *offset = off;
+ return count;
+}
+
+static ssize_t cfam_write(struct file *filep, const char __user *buf,
+ size_t count, loff_t *offset)
+{
+ struct fsi_slave *slave = filep->private_data;
+ size_t total_len, write_len;
+ loff_t off = *offset;
+ ssize_t rc;
+
+
+ if (off < 0)
+ return -EINVAL;
+
+ if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
+ return -EINVAL;
+
+ for (total_len = 0; total_len < count; total_len += write_len) {
+ __be32 data;
+
+ write_len = min_t(size_t, count, 4);
+ write_len -= off & 0x3;
+
+ rc = copy_from_user(&data, buf + total_len, write_len);
+ if (rc) {
+ rc = -EFAULT;
+ goto fail;
+ }
+ rc = fsi_slave_write(slave, off, &data, write_len);
+ if (rc)
+ goto fail;
+ off += write_len;
+ }
+ rc = count;
+ fail:
+ *offset = off;
+ return count;
+}
+
+static loff_t cfam_llseek(struct file *file, loff_t offset, int whence)
+{
+ switch (whence) {
+ case SEEK_CUR:
+ break;
+ case SEEK_SET:
+ file->f_pos = offset;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return offset;
+}
+
+static int cfam_open(struct inode *inode, struct file *file)
+{
+ struct fsi_slave *slave = container_of(inode->i_cdev, struct fsi_slave, cdev);
+
+ file->private_data = slave;
+
+ return 0;
+}
+
+static const struct file_operations cfam_fops = {
+ .owner = THIS_MODULE,
+ .open = cfam_open,
+ .llseek = cfam_llseek,
+ .read = cfam_read,
+ .write = cfam_write,
+};
+
+static ssize_t send_term_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct fsi_slave *slave = to_fsi_slave(dev);
+ struct fsi_master *master = slave->master;
+
+ if (!master->term)
+ return -ENODEV;
+
+ master->term(master, slave->link, slave->id);
+ return count;
+}
+
+static DEVICE_ATTR_WO(send_term);
+
static ssize_t slave_send_echo_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -737,6 +846,52 @@ static ssize_t chip_id_show(struct device *dev,
static DEVICE_ATTR_RO(chip_id);
+static ssize_t cfam_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct fsi_slave *slave = to_fsi_slave(dev);
+
+ return sprintf(buf, "0x%x\n", slave->cfam_id);
+}
+
+static DEVICE_ATTR_RO(cfam_id);
+
+static struct attribute *cfam_attr[] = {
+ &dev_attr_send_echo_delays.attr,
+ &dev_attr_chip_id.attr,
+ &dev_attr_cfam_id.attr,
+ &dev_attr_send_term.attr,
+ NULL,
+};
+
+static const struct attribute_group cfam_attr_group = {
+ .attrs = cfam_attr,
+};
+
+static const struct attribute_group *cfam_attr_groups[] = {
+ &cfam_attr_group,
+ NULL,
+};
+
+static char *cfam_devnode(struct device *dev, umode_t *mode,
+ kuid_t *uid, kgid_t *gid)
+{
+ struct fsi_slave *slave = to_fsi_slave(dev);
+
+#ifdef CONFIG_FSI_NEW_DEV_NODE
+ return kasprintf(GFP_KERNEL, "fsi/cfam%d", slave->cdev_idx);
+#else
+ return kasprintf(GFP_KERNEL, "cfam%d", slave->cdev_idx);
+#endif
+}
+
+static const struct device_type cfam_type = {
+ .name = "cfam",
+ .devnode = cfam_devnode,
+ .groups = cfam_attr_groups
+};
+
static char *fsi_cdev_devnode(struct device *dev, umode_t *mode,
kuid_t *uid, kgid_t *gid)
{
@@ -808,7 +963,7 @@ EXPORT_SYMBOL_GPL(fsi_free_minor);
static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
{
- uint32_t chip_id;
+ uint32_t cfam_id;
struct fsi_slave *slave;
uint8_t crc;
__be32 data, llmode;
@@ -826,17 +981,17 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
link, id, rc);
return -ENODEV;
}
- chip_id = be32_to_cpu(data);
+ cfam_id = be32_to_cpu(data);
- crc = crc4(0, chip_id, 32);
+ crc = crc4(0, cfam_id, 32);
if (crc) {
- dev_warn(&master->dev, "slave %02x:%02x invalid chip id CRC!\n",
+ dev_warn(&master->dev, "slave %02x:%02x invalid cfam id CRC!\n",
link, id);
return -EIO;
}
dev_dbg(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
- chip_id, master->idx, link, id);
+ cfam_id, master->idx, link, id);
/* If we're behind a master that doesn't provide a self-running bus
* clock, put the slave into async mode
@@ -859,10 +1014,14 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
if (!slave)
return -ENOMEM;
- slave->master = master;
+ dev_set_name(&slave->dev, "slave@...x:%02x", link, id);
+ slave->dev.type = &cfam_type;
slave->dev.parent = &master->dev;
slave->dev.of_node = fsi_slave_find_of_node(master, link, id);
slave->dev.release = fsi_slave_release;
+ device_initialize(&slave->dev);
+ slave->cfam_id = cfam_id;
+ slave->master = master;
slave->link = link;
slave->id = id;
slave->size = FSI_SLAVE_SIZE_23b;
@@ -877,6 +1036,21 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
slave->chip_id = prop;
}
+
+ /* Allocate a minor in the FSI space */
+ rc = __fsi_get_new_minor(slave, fsi_dev_cfam, &slave->dev.devt,
+ &slave->cdev_idx);
+ if (rc)
+ goto err_free;
+
+ /* Create chardev for userspace access */
+ cdev_init(&slave->cdev, &cfam_fops);
+ rc = cdev_device_add(&slave->cdev, &slave->dev);
+ if (rc) {
+ dev_err(&slave->dev, "Error %d creating slave device\n", rc);
+ goto err_free;
+ }
+
rc = fsi_slave_set_smode(slave);
if (rc) {
dev_warn(&master->dev,
@@ -890,30 +1064,11 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
slave->t_send_delay,
slave->t_echo_delay);
- dev_set_name(&slave->dev, "slave@...x:%02x", link, id);
- rc = device_register(&slave->dev);
- if (rc < 0) {
- dev_warn(&master->dev, "failed to create slave device: %d\n",
- rc);
- put_device(&slave->dev);
- return rc;
- }
-
+ /* Legacy raw file -> to be removed */
rc = device_create_bin_file(&slave->dev, &fsi_slave_raw_attr);
if (rc)
dev_warn(&slave->dev, "failed to create raw attr: %d\n", rc);
- rc = device_create_bin_file(&slave->dev, &fsi_slave_term_attr);
- if (rc)
- dev_warn(&slave->dev, "failed to create term attr: %d\n", rc);
-
- rc = device_create_file(&slave->dev, &dev_attr_send_echo_delays);
- if (rc)
- dev_warn(&slave->dev, "failed to create delay attr: %d\n", rc);
-
- rc = device_create_file(&slave->dev, &dev_attr_chip_id);
- if (rc)
- dev_warn(&slave->dev, "failed to create chip id: %d\n", rc);
rc = fsi_slave_scan(slave);
if (rc)
@@ -921,6 +1076,10 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
rc);
return rc;
+
+ err_free:
+ put_device(&slave->dev);
+ return rc;
}
/* FSI master support */
@@ -1029,7 +1188,10 @@ static int fsi_slave_remove_device(struct device *dev, void *arg)
static int fsi_master_remove_slave(struct device *dev, void *arg)
{
+ struct fsi_slave *slave = to_fsi_slave(dev);
+
device_for_each_child(dev, NULL, fsi_slave_remove_device);
+ cdev_device_del(&slave->cdev, &slave->dev);
put_device(dev);
return 0;
}
--
2.17.1
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