This makes it possible to read and write USB4 port and retimer sideband
registers through debugfs which is useful for debugging and manufacturing
purposes. We add "sb_regs" debugfs attribute under each USB4 port and
retimer that is used to access the sideband.
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/thunderbolt/debugfs.c | 293 ++++++++++++++++++++++++++++++++++
drivers/thunderbolt/retimer.c | 2 +
drivers/thunderbolt/sb_regs.h | 8 +
drivers/thunderbolt/tb.h | 4 +
4 files changed, 307 insertions(+)
diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
index 70b52aac3d97..5196ece2ded7 100644
--- a/drivers/thunderbolt/debugfs.c
+++ b/drivers/thunderbolt/debugfs.c
@@ -33,6 +33,44 @@
#define COUNTER_SET_LEN 3
+/* Sideband registers and their sizes as defined in the USB4 spec */
+struct sb_reg {
+ unsigned int reg;
+ unsigned int size;
+};
+
+#define SB_MAX_SIZE 64
+
+/* Sideband registers for router */
+static const struct sb_reg port_sb_regs[] = {
+ { USB4_SB_VENDOR_ID, 4 },
+ { USB4_SB_PRODUCT_ID, 4 },
+ { USB4_SB_DEBUG_CONF, 4 },
+ { USB4_SB_DEBUG, 54 },
+ { USB4_SB_LRD_TUNING, 4 },
+ { USB4_SB_OPCODE, 4 },
+ { USB4_SB_METADATA, 4 },
+ { USB4_SB_LINK_CONF, 3 },
+ { USB4_SB_GEN23_TXFFE, 4 },
+ { USB4_SB_GEN4_TXFFE, 4 },
+ { USB4_SB_VERSION, 4 },
+ { USB4_SB_DATA, 64 },
+};
+
+/* Sideband registers for retimer */
+static const struct sb_reg retimer_sb_regs[] = {
+ { USB4_SB_VENDOR_ID, 4 },
+ { USB4_SB_PRODUCT_ID, 4 },
+ { USB4_SB_FW_VERSION, 4 },
+ { USB4_SB_LRD_TUNING, 4 },
+ { USB4_SB_OPCODE, 4 },
+ { USB4_SB_METADATA, 4 },
+ { USB4_SB_GEN23_TXFFE, 4 },
+ { USB4_SB_GEN4_TXFFE, 4 },
+ { USB4_SB_VERSION, 4 },
+ { USB4_SB_DATA, 64 },
+};
+
#define DEBUGFS_ATTR(__space, __write) \
static int __space ## _open(struct inode *inode, struct file *file) \
{ \
@@ -184,10 +222,157 @@ static ssize_t switch_regs_write(struct file *file, const char __user *user_buf,
return regs_write(sw, NULL, user_buf, count, ppos);
}
+
+static bool parse_sb_line(char **line, u8 *reg, u8 *data, size_t data_size,
+ size_t *bytes_read)
+{
+ char *field, *token;
+ int i;
+
+ token = strsep(line, "\n");
+ if (!token)
+ return false;
+
+ /* Parse the register first */
+ field = strsep(&token, " ");
+ if (!field)
+ return false;
+ if (kstrtou8(field, 0, reg))
+ return false;
+
+ /* Then the values for the register, up to data_size */
+ for (i = 0; i < data_size; i++) {
+ field = strsep(&token, " ");
+ if (!field)
+ break;
+ if (kstrtou8(field, 0, &data[i]))
+ return false;
+ }
+
+ *bytes_read = i;
+ return true;
+}
+
+static ssize_t sb_regs_write(struct tb_port *port, const struct sb_reg *sb_regs,
+ size_t size, enum usb4_sb_target target, u8 index,
+ char *buf, size_t count, loff_t *ppos)
+{
+ u8 reg, data[SB_MAX_SIZE];
+ size_t bytes_read;
+ char *line = buf;
+
+ /* User did hardware changes behind the driver's back */
+ add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+
+ /*
+ * For sideband registers we accept:
+ * reg b0 b1 b2...\n
+ *
+ * Here "reg" is the byte offset of the sideband register and "b0"..
+ * are the byte values. There can be less byte values than the register
+ * size. The leftovers will not be overwritten.
+ */
+ while (parse_sb_line(&line, ®, data, ARRAY_SIZE(data), &bytes_read)) {
+ const struct sb_reg *sb_reg;
+ int ret;
+
+ /* At least one byte must be passed */
+ if (bytes_read < 1)
+ return -EINVAL;
+
+ /* Find the register */
+ sb_reg = NULL;
+ for (int i = 0; i < size; i++) {
+ if (sb_regs[i].reg == reg) {
+ sb_reg = &sb_regs[i];
+ break;
+ }
+ }
+
+ if (!sb_reg)
+ return -EINVAL;
+
+ if (bytes_read > sb_regs->size)
+ return -E2BIG;
+
+ ret = usb4_port_sb_write(port, target, index, sb_reg->reg, data,
+ bytes_read);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static ssize_t port_sb_regs_write(struct file *file, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct seq_file *s = file->private_data;
+ struct tb_port *port = s->private;
+ struct tb_switch *sw = port->sw;
+ struct tb *tb = sw->tb;
+ char *buf;
+ int ret;
+
+ buf = validate_and_copy_from_user(user_buf, &count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ pm_runtime_get_sync(&sw->dev);
+
+ if (mutex_lock_interruptible(&tb->lock)) {
+ ret = -ERESTARTSYS;
+ goto out_rpm_put;
+ }
+
+ ret = sb_regs_write(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
+ USB4_SB_TARGET_ROUTER, 0, buf, count, ppos);
+
+ mutex_unlock(&tb->lock);
+out_rpm_put:
+ pm_runtime_mark_last_busy(&sw->dev);
+ pm_runtime_put_autosuspend(&sw->dev);
+
+ return ret < 0 ? ret : count;
+}
+
+static ssize_t retimer_sb_regs_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct seq_file *s = file->private_data;
+ struct tb_retimer *rt = s->private;
+ struct tb *tb = rt->tb;
+ char *buf;
+ int ret;
+
+ buf = validate_and_copy_from_user(user_buf, &count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ pm_runtime_get_sync(&rt->dev);
+
+ if (mutex_lock_interruptible(&tb->lock)) {
+ ret = -ERESTARTSYS;
+ goto out_rpm_put;
+ }
+
+ ret = sb_regs_write(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
+ USB4_SB_TARGET_RETIMER, rt->index, buf, count, ppos);
+
+ mutex_unlock(&tb->lock);
+out_rpm_put:
+ pm_runtime_mark_last_busy(&rt->dev);
+ pm_runtime_put_autosuspend(&rt->dev);
+
+ return ret < 0 ? ret : count;
+}
#define DEBUGFS_MODE 0600
#else
#define port_regs_write NULL
#define switch_regs_write NULL
+#define port_sb_regs_write NULL
+#define retimer_sb_regs_write NULL
#define DEBUGFS_MODE 0400
#endif
@@ -1505,6 +1690,60 @@ static int counters_show(struct seq_file *s, void *not_used)
}
DEBUGFS_ATTR_RW(counters);
+static int sb_regs_show(struct tb_port *port, const struct sb_reg *sb_regs,
+ size_t size, enum usb4_sb_target target, u8 index,
+ struct seq_file *s)
+{
+ int ret, i;
+
+ seq_puts(s, "# register value\n");
+
+ for (i = 0; i < size; i++) {
+ const struct sb_reg *regs = &sb_regs[i];
+ u8 data[64];
+ int j;
+
+ memset(data, 0, sizeof(data));
+ ret = usb4_port_sb_read(port, target, index, regs->reg, data,
+ regs->size);
+ if (ret)
+ return ret;
+
+ seq_printf(s, "0x%02x", regs->reg);
+ for (j = 0; j < regs->size; j++)
+ seq_printf(s, " 0x%02x", data[j]);
+ seq_puts(s, "\n");
+ }
+
+ return 0;
+}
+
+static int port_sb_regs_show(struct seq_file *s, void *not_used)
+{
+ struct tb_port *port = s->private;
+ struct tb_switch *sw = port->sw;
+ struct tb *tb = sw->tb;
+ int ret;
+
+ pm_runtime_get_sync(&sw->dev);
+
+ if (mutex_lock_interruptible(&tb->lock)) {
+ ret = -ERESTARTSYS;
+ goto out_rpm_put;
+ }
+
+ ret = sb_regs_show(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
+ USB4_SB_TARGET_ROUTER, 0, s);
+
+ mutex_unlock(&tb->lock);
+out_rpm_put:
+ pm_runtime_mark_last_busy(&sw->dev);
+ pm_runtime_put_autosuspend(&sw->dev);
+
+ return ret;
+}
+DEBUGFS_ATTR_RW(port_sb_regs);
+
/**
* tb_switch_debugfs_init() - Add debugfs entries for router
* @sw: Pointer to the router
@@ -1539,6 +1778,9 @@ void tb_switch_debugfs_init(struct tb_switch *sw)
if (port->config.counters_support)
debugfs_create_file("counters", 0600, debugfs_dir, port,
&counters_fops);
+ if (port->usb4)
+ debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir,
+ port, &port_sb_regs_fops);
}
margining_switch_init(sw);
@@ -1590,6 +1832,57 @@ void tb_service_debugfs_remove(struct tb_service *svc)
svc->debugfs_dir = NULL;
}
+static int retimer_sb_regs_show(struct seq_file *s, void *not_used)
+{
+ struct tb_retimer *rt = s->private;
+ struct tb *tb = rt->tb;
+ int ret;
+
+ pm_runtime_get_sync(&rt->dev);
+
+ if (mutex_lock_interruptible(&tb->lock)) {
+ ret = -ERESTARTSYS;
+ goto out_rpm_put;
+ }
+
+ ret = sb_regs_show(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
+ USB4_SB_TARGET_RETIMER, rt->index, s);
+
+ mutex_unlock(&tb->lock);
+out_rpm_put:
+ pm_runtime_mark_last_busy(&rt->dev);
+ pm_runtime_put_autosuspend(&rt->dev);
+
+ return ret;
+}
+DEBUGFS_ATTR_RW(retimer_sb_regs);
+
+/**
+ * tb_retimer_debugfs_init() - Add debugfs directory for retimer
+ * @rt: Pointer to retimer structure
+ *
+ * Adds and populates retimer debugfs directory.
+ */
+void tb_retimer_debugfs_init(struct tb_retimer *rt)
+{
+ struct dentry *debugfs_dir;
+
+ debugfs_dir = debugfs_create_dir(dev_name(&rt->dev), tb_debugfs_root);
+ debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir, rt,
+ &retimer_sb_regs_fops);
+}
+
+/**
+ * tb_retimer_debugfs_remove() - Remove retimer debugfs directory
+ * @rt: Pointer to retimer structure
+ *
+ * Removes the retimer debugfs directory along with its contents.
+ */
+void tb_retimer_debugfs_remove(struct tb_retimer *rt)
+{
+ debugfs_lookup_and_remove(dev_name(&rt->dev), tb_debugfs_root);
+}
+
void tb_debugfs_init(void)
{
tb_debugfs_root = debugfs_create_dir("thunderbolt", NULL);
diff --git a/drivers/thunderbolt/retimer.c b/drivers/thunderbolt/retimer.c
index 9b66bff98f7e..8ce1dc7bbfad 100644
--- a/drivers/thunderbolt/retimer.c
+++ b/drivers/thunderbolt/retimer.c
@@ -437,12 +437,14 @@ static int tb_retimer_add(struct tb_port *port, u8 index, u32 auth_status)
pm_runtime_mark_last_busy(&rt->dev);
pm_runtime_use_autosuspend(&rt->dev);
+ tb_retimer_debugfs_init(rt);
return 0;
}
static void tb_retimer_remove(struct tb_retimer *rt)
{
dev_info(&rt->dev, "retimer disconnected\n");
+ tb_retimer_debugfs_remove(rt);
tb_nvm_free(rt->nvm);
device_unregister(&rt->dev);
}
diff --git a/drivers/thunderbolt/sb_regs.h b/drivers/thunderbolt/sb_regs.h
index f37a4320f10a..b2a6add82161 100644
--- a/drivers/thunderbolt/sb_regs.h
+++ b/drivers/thunderbolt/sb_regs.h
@@ -12,6 +12,10 @@
#define USB4_SB_VENDOR_ID 0x00
#define USB4_SB_PRODUCT_ID 0x01
+#define USB4_SB_FW_VERSION 0x02
+#define USB4_SB_DEBUG_CONF 0x05
+#define USB4_SB_DEBUG 0x06
+#define USB4_SB_LRD_TUNING 0x07
#define USB4_SB_OPCODE 0x08
enum usb4_sb_opcode {
@@ -35,6 +39,10 @@ enum usb4_sb_opcode {
#define USB4_SB_METADATA 0x09
#define USB4_SB_METADATA_NVM_AUTH_WRITE_MASK GENMASK(5, 0)
+#define USB4_SB_LINK_CONF 0x0c
+#define USB4_SB_GEN23_TXFFE 0x0d
+#define USB4_SB_GEN4_TXFFE 0x0e
+#define USB4_SB_VERSION 0x0f
#define USB4_SB_DATA 0x12
/* USB4_SB_OPCODE_READ_LANE_MARGINING_CAP */
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index ab3366fcb0a3..1a53d18223d9 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1458,6 +1458,8 @@ void tb_xdomain_debugfs_init(struct tb_xdomain *xd);
void tb_xdomain_debugfs_remove(struct tb_xdomain *xd);
void tb_service_debugfs_init(struct tb_service *svc);
void tb_service_debugfs_remove(struct tb_service *svc);
+void tb_retimer_debugfs_init(struct tb_retimer *rt);
+void tb_retimer_debugfs_remove(struct tb_retimer *rt);
#else
static inline void tb_debugfs_init(void) { }
static inline void tb_debugfs_exit(void) { }
@@ -1467,6 +1469,8 @@ static inline void tb_xdomain_debugfs_init(struct tb_xdomain *xd) { }
static inline void tb_xdomain_debugfs_remove(struct tb_xdomain *xd) { }
static inline void tb_service_debugfs_init(struct tb_service *svc) { }
static inline void tb_service_debugfs_remove(struct tb_service *svc) { }
+static inline void tb_retimer_debugfs_init(struct tb_retimer *rt) { }
+static inline void tb_retimer_debugfs_remove(struct tb_retimer *rt) { }
#endif
#endif
--
2.43.0
