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Subject[PATCH v2 6/9] NTB: Add Messaging NTB API
Date
Some IDT NTB-capable PCIe-switches have message registers to communicate with
peer devices. This patch adds new NTB API callback methods, which can be used
to utilize these registers functionality:
ntb_msg_count(); - get number of message registers
ntb_msg_inbits(); - get bitfield of inbound message registers status
ntb_msg_outbits(); - get bitfield of outbound message registers status
ntb_msg_read_sts(); - read the inbound and outbound message registers status
ntb_msg_clear_sts(); - clear status bits of message registers
ntb_msg_set_mask(); - mask interrupts raised by status bits of message
registers.
ntb_msg_clear_mask(); - clear interrupts mask bits of message registers
ntb_msg_read(midx, *pidx); - read message register with specified index,
additionally getting peer port index which data received from
ntb_msg_write(midx, pidx); - write data to the specified message register
sending it to the passed peer device connected over a pidx port
ntb_msg_event(); - notify driver context of a new message event

Of course there is hadrware which doesn't support Message registers, so
this API is made optional.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

---
drivers/ntb/ntb.c | 13 ++++
include/linux/ntb.h | 205 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 218 insertions(+)

diff --git a/drivers/ntb/ntb.c b/drivers/ntb/ntb.c
index f6153af..06574f8 100644
--- a/drivers/ntb/ntb.c
+++ b/drivers/ntb/ntb.c
@@ -193,6 +193,19 @@ void ntb_db_event(struct ntb_dev *ntb, int vector)
}
EXPORT_SYMBOL(ntb_db_event);

+void ntb_msg_event(struct ntb_dev *ntb)
+{
+ unsigned long irqflags;
+
+ spin_lock_irqsave(&ntb->ctx_lock, irqflags);
+ {
+ if (ntb->ctx_ops && ntb->ctx_ops->msg_event)
+ ntb->ctx_ops->msg_event(ntb->ctx);
+ }
+ spin_unlock_irqrestore(&ntb->ctx_lock, irqflags);
+}
+EXPORT_SYMBOL(ntb_msg_event);
+
static int ntb_probe(struct device *dev)
{
struct ntb_dev *ntb;
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index a6bf15d..90746df 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -164,10 +164,12 @@ static inline int ntb_client_ops_is_valid(const struct ntb_client_ops *ops)
* struct ntb_ctx_ops - ntb driver context operations
* @link_event: See ntb_link_event().
* @db_event: See ntb_db_event().
+ * @msg_event: See ntb_msg_event().
*/
struct ntb_ctx_ops {
void (*link_event)(void *ctx);
void (*db_event)(void *ctx, int db_vector);
+ void (*msg_event)(void *ctx);
};

static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
@@ -176,6 +178,7 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
return
/* ops->link_event && */
/* ops->db_event && */
+ /* ops->msg_event && */
1;
}

@@ -220,6 +223,15 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
* @peer_spad_addr: See ntb_peer_spad_addr().
* @peer_spad_read: See ntb_peer_spad_read().
* @peer_spad_write: See ntb_peer_spad_write().
+ * @msg_count: See ntb_msg_count().
+ * @msg_inbits: See ntb_msg_inbits().
+ * @msg_outbits: See ntb_msg_outbits().
+ * @msg_read_sts: See ntb_msg_read_sts().
+ * @msg_clear_sts: See ntb_msg_clear_sts().
+ * @msg_set_mask: See ntb_msg_set_mask().
+ * @msg_clear_mask: See ntb_msg_clear_mask().
+ * @msg_read: See ntb_msg_read().
+ * @msg_write: See ntb_msg_write().
*/
struct ntb_dev_ops {
int (*port_number)(struct ntb_dev *ntb);
@@ -282,6 +294,16 @@ struct ntb_dev_ops {
u32 (*peer_spad_read)(struct ntb_dev *ntb, int pidx, int sidx);
int (*peer_spad_write)(struct ntb_dev *ntb, int pidx, int sidx,
u32 val);
+
+ int (*msg_count)(struct ntb_dev *ntb);
+ u64 (*msg_inbits)(struct ntb_dev *ntb);
+ u64 (*msg_outbits)(struct ntb_dev *ntb);
+ u64 (*msg_read_sts)(struct ntb_dev *ntb);
+ int (*msg_clear_sts)(struct ntb_dev *ntb, u64 sts_bits);
+ int (*msg_set_mask)(struct ntb_dev *ntb, u64 mask_bits);
+ int (*msg_clear_mask)(struct ntb_dev *ntb, u64 mask_bits);
+ int (*msg_read)(struct ntb_dev *ntb, int midx, int *pidx, u32 *msg);
+ int (*msg_write)(struct ntb_dev *ntb, int midx, int pidx, u32 msg);
};

static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
@@ -329,6 +351,15 @@ static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
/* !ops->peer_spad_addr == !ops->spad_count && */
/* !ops->peer_spad_read == !ops->spad_count && */
!ops->peer_spad_write == !ops->spad_count &&
+
+ !ops->msg_inbits == !ops->msg_count &&
+ !ops->msg_outbits == !ops->msg_count &&
+ !ops->msg_read_sts == !ops->msg_count &&
+ !ops->msg_clear_sts == !ops->msg_count &&
+ /* !ops->msg_set_mask == !ops->msg_count && */
+ /* !ops->msg_clear_mask == !ops->msg_count && */
+ !ops->msg_read == !ops->msg_count &&
+ !ops->msg_write == !ops->msg_count &&
1;
}

@@ -472,6 +503,18 @@ void ntb_link_event(struct ntb_dev *ntb);
void ntb_db_event(struct ntb_dev *ntb, int vector);

/**
+ * ntb_msg_event() - notify driver context of a message event
+ * @ntb: NTB device context.
+ *
+ * Notify the driver context of a message event. If hardware supports
+ * message registers, this event indicates, that a new message arrived in
+ * some incoming message register or last sent message couldn't be delivered.
+ * The events can be masked/unmasked by the methods ntb_msg_set_mask() and
+ * ntb_msg_clear_mask().
+ */
+void ntb_msg_event(struct ntb_dev *ntb);
+
+/**
* ntb_port_number() - get the local port number
* @ntb: NTB device context.
*
@@ -1197,4 +1240,166 @@ static inline int ntb_peer_spad_write(struct ntb_dev *ntb, int pidx, int sidx,
return ntb->ops->peer_spad_write(ntb, pidx, sidx, val);
}

+/**
+ * ntb_msg_count() - get the number of message registers
+ * @ntb: NTB device context.
+ *
+ * Hardware may support a different number of messge registers.
+ *
+ * Return: the number of message registers.
+ */
+static inline int ntb_msg_count(struct ntb_dev *ntb)
+{
+ if (!ntb->ops->msg_count)
+ return 0;
+
+ return ntb->ops->msg_count(ntb);
+}
+
+/**
+ * ntb_msg_inbits() - get a bitsfield of inbound message registers status
+ * @ntb: NTB device context.
+ *
+ * The method returns the bitsfield of status and mask registers, which related
+ * to inbound message registers.
+ *
+ * Return: bitsfield of inbound message registers.
+ */
+static inline u64 ntb_msg_inbits(struct ntb_dev *ntb)
+{
+ if (!ntb->ops->msg_inbits)
+ return 0;
+
+ return ntb->ops->msg_inbits(ntb);
+}
+
+/**
+ * ntb_msg_outbits() - get a bitsfield of outbound message registers status
+ * @ntb: NTB device context.
+ *
+ * The method returns the bitsfield of status and mask registers, which related
+ * to outbound message registers.
+ *
+ * Return: bitsfield of outbound message registers.
+ */
+static inline u64 ntb_msg_outbits(struct ntb_dev *ntb)
+{
+ if (!ntb->ops->msg_outbits)
+ return 0;
+
+ return ntb->ops->msg_outbits(ntb);
+}
+
+/**
+ * ntb_msg_read_sts() - read the message registers status
+ * @ntb: NTB device context.
+ *
+ * Read the status of message register. Inbound and outbound message registers
+ * related bits can be filetered by masks retrieved from ntb_msg_inbits() and
+ * ntb_msg_outbits().
+ *
+ * Return: status bits of message registers
+ */
+static inline u64 ntb_msg_read_sts(struct ntb_dev *ntb)
+{
+ if (!ntb->ops->msg_read_sts)
+ return 0;
+
+ return ntb->ops->msg_read_sts(ntb);
+}
+
+/**
+ * ntb_msg_clear_sts() - clear status bits of message registers
+ * @ntb: NTB device context.
+ * @sts_bits: Status bits to clear.
+ *
+ * Clear bits in the status register.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+static inline int ntb_msg_clear_sts(struct ntb_dev *ntb, u64 sts_bits)
+{
+ if (!ntb->ops->msg_clear_sts)
+ return -EINVAL;
+
+ return ntb->ops->msg_clear_sts(ntb, sts_bits);
+}
+
+/**
+ * ntb_msg_set_mask() - set mask of message register status bits
+ * @ntb: NTB device context.
+ * @mask_bits: Mask bits.
+ *
+ * Mask the message registers status bits from raising the message event.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+static inline int ntb_msg_set_mask(struct ntb_dev *ntb, u64 mask_bits)
+{
+ if (!ntb->ops->msg_set_mask)
+ return -EINVAL;
+
+ return ntb->ops->msg_set_mask(ntb, mask_bits);
+}
+
+/**
+ * ntb_msg_clear_mask() - clear message registers mask
+ * @ntb: NTB device context.
+ * @mask_bits: Mask bits to clear.
+ *
+ * Clear bits in the message events mask register.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+static inline int ntb_msg_clear_mask(struct ntb_dev *ntb, u64 mask_bits)
+{
+ if (!ntb->ops->msg_clear_mask)
+ return -EINVAL;
+
+ return ntb->ops->msg_clear_mask(ntb, mask_bits);
+}
+
+/**
+ * ntb_msg_read() - read message register with specified index
+ * @ntb: NTB device context.
+ * @midx: Message register index
+ * @pidx: OUT - Port index of peer device a message retrieved from
+ * @msg: OUT - Data
+ *
+ * Read data from the specified message register. Source port index of a
+ * message is retrieved as well.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+static inline int ntb_msg_read(struct ntb_dev *ntb, int midx, int *pidx,
+ u32 *msg)
+{
+ if (!ntb->ops->msg_read)
+ return -EINVAL;
+
+ return ntb->ops->msg_read(ntb, midx, pidx, msg);
+}
+
+/**
+ * ntb_msg_write() - write data to the specified message register
+ * @ntb: NTB device context.
+ * @midx: Message register index
+ * @pidx: Port index of peer device a message being sent to
+ * @msg: Data to send
+ *
+ * Send data to a specified peer device using the defined message register.
+ * Message event can be raised if the midx registers isn't empty while
+ * calling this method and the corresponding interrupt isn't masked.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+static inline int ntb_msg_write(struct ntb_dev *ntb, int midx, int pidx,
+ u32 msg)
+{
+ if (!ntb->ops->msg_write)
+ return -EINVAL;
+
+ return ntb->ops->msg_write(ntb, midx, pidx, msg);
+}
+
#endif
--
2.6.6
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