diff options
Diffstat (limited to 'drivers/slimbus')
| -rw-r--r-- | drivers/slimbus/Makefile | 2 | ||||
| -rw-r--r-- | drivers/slimbus/messaging.c | 297 | ||||
| -rw-r--r-- | drivers/slimbus/slimbus.h | 67 |
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 */ |