summaryrefslogtreecommitdiff
path: root/drivers/slimbus
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/slimbus')
-rw-r--r--drivers/slimbus/Makefile2
-rw-r--r--drivers/slimbus/messaging.c297
-rw-r--r--drivers/slimbus/slimbus.h67
3 files changed, 365 insertions, 1 deletions
diff --git a/drivers/slimbus/Makefile b/drivers/slimbus/Makefile
index 506ff17d6346..568a14c7be78 100644
--- a/drivers/slimbus/Makefile
+++ b/drivers/slimbus/Makefile
@@ -3,4 +3,4 @@
# Makefile for kernel SLIMbus framework.
#
obj-$(CONFIG_SLIMBUS) += slimbus.o
-slimbus-y := core.o
+slimbus-y := core.o messaging.o
diff --git a/drivers/slimbus/messaging.c b/drivers/slimbus/messaging.c
new file mode 100644
index 000000000000..031e67648d7c
--- /dev/null
+++ b/drivers/slimbus/messaging.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2011-2017, The Linux Foundation
+ */
+
+#include <linux/slab.h>
+#include "slimbus.h"
+
+/**
+ * slim_msg_response() - Deliver Message response received from a device to the
+ * framework.
+ *
+ * @ctrl: Controller handle
+ * @reply: Reply received from the device
+ * @len: Length of the reply
+ * @tid: Transaction ID received with which framework can associate reply.
+ *
+ * Called by controller to inform framework about the response received.
+ * This helps in making the API asynchronous, and controller-driver doesn't need
+ * to manage 1 more table other than the one managed by framework mapping TID
+ * with buffers
+ */
+void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
+{
+ struct slim_msg_txn *txn;
+ struct slim_val_inf *msg;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ctrl->txn_lock, flags);
+ txn = idr_find(&ctrl->tid_idr, tid);
+ if (txn == NULL) {
+ spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+ return;
+ }
+
+ msg = txn->msg;
+ if (msg == NULL || msg->rbuf == NULL) {
+ dev_err(ctrl->dev, "Got response to invalid TID:%d, len:%d\n",
+ tid, len);
+ return;
+ }
+
+ idr_remove(&ctrl->tid_idr, tid);
+ spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+ memcpy(msg->rbuf, reply, len);
+ if (txn->comp)
+ complete(txn->comp);
+}
+EXPORT_SYMBOL_GPL(slim_msg_response);
+
+/**
+ * slim_do_transfer() - Process a SLIMbus-messaging transaction
+ *
+ * @ctrl: Controller handle
+ * @txn: Transaction to be sent over SLIMbus
+ *
+ * Called by controller to transmit messaging transactions not dealing with
+ * Interface/Value elements. (e.g. transmittting a message to assign logical
+ * address to a slave device
+ *
+ * Return: -ETIMEDOUT: If transmission of this message timed out
+ * (e.g. due to bus lines not being clocked or driven by controller)
+ */
+int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
+{
+ DECLARE_COMPLETION_ONSTACK(done);
+ bool need_tid;
+ unsigned long flags;
+ int ret, tid, timeout;
+
+ need_tid = slim_tid_txn(txn->mt, txn->mc);
+
+ if (need_tid) {
+ spin_lock_irqsave(&ctrl->txn_lock, flags);
+ tid = idr_alloc(&ctrl->tid_idr, txn, 0,
+ SLIM_MAX_TIDS, GFP_KERNEL);
+ txn->tid = tid;
+
+ if (!txn->msg->comp)
+ txn->comp = &done;
+ else
+ txn->comp = txn->comp;
+
+ spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+
+ if (tid < 0)
+ return tid;
+ }
+
+ ret = ctrl->xfer_msg(ctrl, txn);
+
+ if (ret && need_tid && !txn->msg->comp) {
+ unsigned long ms = txn->rl + HZ;
+
+ timeout = wait_for_completion_timeout(txn->comp,
+ msecs_to_jiffies(ms));
+ if (!timeout) {
+ ret = -ETIMEDOUT;
+ spin_lock_irqsave(&ctrl->txn_lock, flags);
+ idr_remove(&ctrl->tid_idr, tid);
+ spin_unlock_irqrestore(&ctrl->txn_lock, flags);
+ }
+ }
+
+ if (ret)
+ dev_err(ctrl->dev, "Tx:MT:0x%x, MC:0x%x, LA:0x%x failed:%d\n",
+ txn->mt, txn->mc, txn->la, ret);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(slim_do_transfer);
+
+static int slim_val_inf_sanity(struct slim_controller *ctrl,
+ struct slim_val_inf *msg, u8 mc)
+{
+ if (!msg || msg->num_bytes > 16 ||
+ (msg->start_offset + msg->num_bytes) > 0xC00)
+ goto reterr;
+ switch (mc) {
+ case SLIM_MSG_MC_REQUEST_VALUE:
+ case SLIM_MSG_MC_REQUEST_INFORMATION:
+ if (msg->rbuf != NULL)
+ return 0;
+ break;
+
+ case SLIM_MSG_MC_CHANGE_VALUE:
+ case SLIM_MSG_MC_CLEAR_INFORMATION:
+ if (msg->wbuf != NULL)
+ return 0;
+ break;
+
+ case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
+ case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
+ if (msg->rbuf != NULL && msg->wbuf != NULL)
+ return 0;
+ break;
+ }
+reterr:
+ dev_err(ctrl->dev, "Sanity check failed:msg:offset:0x%x, mc:%d\n",
+ msg->start_offset, mc);
+ return -EINVAL;
+}
+
+static u16 slim_slicesize(int code)
+{
+ static const u8 sizetocode[16] = {
+ 0, 1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7
+ };
+
+ clamp(code, 1, (int)ARRAY_SIZE(sizetocode));
+
+ return sizetocode[code - 1];
+}
+
+/**
+ * slim_xfer_msg() - Transfer a value info message on slim device
+ *
+ * @sbdev: slim device to which this msg has to be transfered
+ * @msg: value info message pointer
+ * @mc: message code of the message
+ *
+ * Called by drivers which want to transfer a vlaue or info elements.
+ *
+ * Return: -ETIMEDOUT: If transmission of this message timed out
+ */
+int slim_xfer_msg(struct slim_device *sbdev, struct slim_val_inf *msg,
+ u8 mc)
+{
+ DEFINE_SLIM_LDEST_TXN(txn_stack, mc, 6, sbdev->laddr, msg);
+ struct slim_msg_txn *txn = &txn_stack;
+ struct slim_controller *ctrl = sbdev->ctrl;
+ int ret;
+ u16 sl;
+
+ if (!ctrl)
+ return -EINVAL;
+
+ ret = slim_val_inf_sanity(ctrl, msg, mc);
+ if (ret)
+ return ret;
+
+ sl = slim_slicesize(msg->num_bytes);
+
+ dev_dbg(ctrl->dev, "SB xfer msg:os:%x, len:%d, MC:%x, sl:%x\n",
+ msg->start_offset, msg->num_bytes, mc, sl);
+
+ txn->ec = ((sl | (1 << 3)) | ((msg->start_offset & 0xFFF) << 4));
+
+ switch (mc) {
+ case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
+ case SLIM_MSG_MC_CHANGE_VALUE:
+ case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
+ case SLIM_MSG_MC_CLEAR_INFORMATION:
+ txn->rl += msg->num_bytes;
+ default:
+ break;
+ }
+
+ if (slim_tid_txn(txn->mt, txn->mc))
+ txn->rl++;
+
+ return slim_do_transfer(ctrl, txn);
+}
+EXPORT_SYMBOL_GPL(slim_xfer_msg);
+
+static void slim_fill_msg(struct slim_val_inf *msg, u32 addr,
+ size_t count, u8 *rbuf, u8 *wbuf)
+{
+ msg->start_offset = addr;
+ msg->num_bytes = count;
+ msg->rbuf = rbuf;
+ msg->wbuf = wbuf;
+}
+
+/**
+ * slim_read() - Read SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr: address of value element to read.
+ * @count: number of bytes to read. Maximum bytes allowed are 16.
+ * @val: will return what the value element value was
+ *
+ * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
+ * this message timed out (e.g. due to bus lines not being clocked
+ * or driven by controller)
+ */
+int slim_read(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
+{
+ struct slim_val_inf msg;
+
+ slim_fill_msg(&msg, addr, count, val, NULL);
+
+ return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_REQUEST_VALUE);
+}
+EXPORT_SYMBOL_GPL(slim_read);
+
+/**
+ * slim_readb() - Read byte from SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr: address in the value element to read.
+ *
+ * Return: byte value of value element.
+ */
+int slim_readb(struct slim_device *sdev, u32 addr)
+{
+ int ret;
+ u8 buf;
+
+ ret = slim_read(sdev, addr, 1, &buf);
+ if (ret < 0)
+ return ret;
+ else
+ return buf;
+}
+EXPORT_SYMBOL_GPL(slim_readb);
+
+/**
+ * slim_write() - Write SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr: address in the value element to write.
+ * @count: number of bytes to write. Maximum bytes allowed are 16.
+ * @val: value to write to value element
+ *
+ * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
+ * this message timed out (e.g. due to bus lines not being clocked
+ * or driven by controller)
+ */
+int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
+{
+ struct slim_val_inf msg;
+
+ slim_fill_msg(&msg, addr, count, val, NULL);
+
+ return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_CHANGE_VALUE);
+}
+EXPORT_SYMBOL_GPL(slim_write);
+
+/**
+ * slim_writeb() - Write byte to SLIMbus value element
+ *
+ * @sdev: client handle.
+ * @addr: address of value element to write.
+ * @value: value to write to value element
+ *
+ * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
+ * this message timed out (e.g. due to bus lines not being clocked
+ * or driven by controller)
+ *
+ */
+int slim_writeb(struct slim_device *sdev, u32 addr, u8 value)
+{
+ return slim_write(sdev, addr, 1, &value);
+}
+EXPORT_SYMBOL_GPL(slim_writeb);
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
index 66657722f50f..0d40c2578c28 100644
--- a/drivers/slimbus/slimbus.h
+++ b/drivers/slimbus/slimbus.h
@@ -8,8 +8,17 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
+#include <linux/completion.h>
#include <linux/slimbus.h>
+/* SLIMbus message types. Related to interpretation of message code. */
+#define SLIM_MSG_MT_CORE 0x0
+
+/* Destination type Values */
+#define SLIM_MSG_DEST_LOGICALADDR 0
+#define SLIM_MSG_DEST_ENUMADDR 1
+#define SLIM_MSG_DEST_BROADCAST 3
+
/* Standard values per SLIMbus spec needed by controllers and devices */
#define SLIM_MAX_CLK_GEAR 10
#define SLIM_MIN_CLK_GEAR 1
@@ -17,6 +26,7 @@
/* Manager's logical address is set to 0xFF per spec */
#define SLIM_LA_MANAGER 0xFF
+#define SLIM_MAX_TIDS 256
/**
* struct slim_framer - Represents SLIMbus framer.
* Every controller may have multiple framers. There is 1 active framer device
@@ -38,6 +48,39 @@ struct slim_framer {
#define to_slim_framer(d) container_of(d, struct slim_framer, dev)
/**
+ * struct slim_msg_txn - Message to be sent by the controller.
+ * This structure has packet header,
+ * payload and buffer to be filled (if any)
+ * @rl: Header field. remaining length.
+ * @mt: Header field. Message type.
+ * @mc: Header field. LSB is message code for type mt.
+ * @dt: Header field. Destination type.
+ * @ec: Element code. Used for elemental access APIs.
+ * @tid: Transaction ID. Used for messages expecting response.
+ * (relevant for message-codes involving read operation)
+ * @la: Logical address of the device this message is going to.
+ * (Not used when destination type is broadcast.)
+ * @msg: Elemental access message to be read/written
+ * @comp: completion if read/write is synchronous, used internally
+ * for tid based transactions.
+ */
+struct slim_msg_txn {
+ u8 rl;
+ u8 mt;
+ u8 mc;
+ u8 dt;
+ u16 ec;
+ u8 tid;
+ u8 la;
+ struct slim_val_inf *msg;
+ struct completion *comp;
+};
+
+/* Frequently used message transaction structures */
+#define DEFINE_SLIM_LDEST_TXN(name, mc, rl, la, msg) \
+ struct slim_msg_txn name = { rl, 0, mc, SLIM_MSG_DEST_LOGICALADDR, 0,\
+ 0, la, msg, }
+/**
* struct slim_controller - Controls every instance of SLIMbus
* (similar to 'master' on SPI)
* @dev: Device interface to this driver
@@ -52,6 +95,9 @@ struct slim_framer {
* @devices: Slim device list
* @tid_idr: tid id allocator
* @txn_lock: Lock to protect table of transactions
+ * @xfer_msg: Transfer a message on this controller (this can be a broadcast
+ * control/status message like data channel setup, or a unicast message
+ * like value element read/write.
* @set_laddr: Setup logical address at laddr for the slave with elemental
* address e_addr. Drivers implementing controller will be expected to
* send unicast message to this device with its logical address.
@@ -93,6 +139,8 @@ struct slim_controller {
struct list_head devices;
struct idr tid_idr;
spinlock_t txn_lock;
+ int (*xfer_msg)(struct slim_controller *ctrl,
+ struct slim_msg_txn *tx);
int (*set_laddr)(struct slim_controller *ctrl,
struct slim_eaddr *ea, u8 laddr);
int (*get_laddr)(struct slim_controller *ctrl,
@@ -104,5 +152,24 @@ int slim_device_report_present(struct slim_controller *ctrl,
void slim_report_absent(struct slim_device *sbdev);
int slim_register_controller(struct slim_controller *ctrl);
int slim_unregister_controller(struct slim_controller *ctrl);
+void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 l);
+int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn);
+
+static inline bool slim_tid_txn(u8 mt, u8 mc)
+{
+ return (mt == SLIM_MSG_MT_CORE &&
+ (mc == SLIM_MSG_MC_REQUEST_INFORMATION ||
+ mc == SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION ||
+ mc == SLIM_MSG_MC_REQUEST_VALUE ||
+ mc == SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION));
+}
+static inline bool slim_ec_txn(u8 mt, u8 mc)
+{
+ return (mt == SLIM_MSG_MT_CORE &&
+ ((mc >= SLIM_MSG_MC_REQUEST_INFORMATION &&
+ mc <= SLIM_MSG_MC_REPORT_INFORMATION) ||
+ (mc >= SLIM_MSG_MC_REQUEST_VALUE &&
+ mc <= SLIM_MSG_MC_CHANGE_VALUE)));
+}
#endif /* _LINUX_SLIMBUS_H */