diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index c2b10e2c75f0..f68d92b57543 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2106,6 +2106,41 @@ struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr) } EXPORT_SYMBOL_GPL(spi_get_next_queued_message); +/* + * __spi_unoptimize_message - shared implementation of spi_unoptimize_message() + * and spi_maybe_unoptimize_message() + * @msg: the message to unoptimize + * + * Peripheral drivers should use spi_unoptimize_message() and callers inside + * core should use spi_maybe_unoptimize_message() rather than calling this + * function directly. + * + * It is not valid to call this on a message that is not currently optimized. + */ +static void __spi_unoptimize_message(struct spi_message *msg) +{ + struct spi_controller *ctlr = msg->spi->controller; + + if (ctlr->unoptimize_message) + ctlr->unoptimize_message(msg); + + msg->optimized = false; + msg->opt_state = NULL; +} + +/* + * spi_maybe_unoptimize_message - unoptimize msg not managed by a peripheral + * @msg: the message to unoptimize + * + * This function is used to unoptimize a message if and only if it was + * optimized by the core (via spi_maybe_optimize_message()). + */ +static void spi_maybe_unoptimize_message(struct spi_message *msg) +{ + if (!msg->pre_optimized && msg->optimized) + __spi_unoptimize_message(msg); +} + /** * spi_finalize_current_message() - the current message is complete * @ctlr: the controller to return the message to @@ -2153,6 +2188,8 @@ void spi_finalize_current_message(struct spi_controller *ctlr) mesg->prepared = false; + spi_maybe_unoptimize_message(mesg); + WRITE_ONCE(ctlr->cur_msg_incomplete, false); smp_mb(); /* See __spi_pump_transfer_message()... */ if (READ_ONCE(ctlr->cur_msg_need_completion)) @@ -4194,6 +4231,110 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) return 0; } +/* + * __spi_optimize_message - shared implementation for spi_optimize_message() + * and spi_maybe_optimize_message() + * @spi: the device that will be used for the message + * @msg: the message to optimize + * + * Peripheral drivers will call spi_optimize_message() and the spi core will + * call spi_maybe_optimize_message() instead of calling this directly. + * + * It is not valid to call this on a message that has already been optimized. + * + * Return: zero on success, else a negative error code + */ +static int __spi_optimize_message(struct spi_device *spi, + struct spi_message *msg) +{ + struct spi_controller *ctlr = spi->controller; + int ret; + + ret = __spi_validate(spi, msg); + if (ret) + return ret; + + if (ctlr->optimize_message) { + ret = ctlr->optimize_message(msg); + if (ret) + return ret; + } + + msg->optimized = true; + + return 0; +} + +/* + * spi_maybe_optimize_message - optimize message if it isn't already pre-optimized + * @spi: the device that will be used for the message + * @msg: the message to optimize + * Return: zero on success, else a negative error code + */ +static int spi_maybe_optimize_message(struct spi_device *spi, + struct spi_message *msg) +{ + if (msg->pre_optimized) + return 0; + + return __spi_optimize_message(spi, msg); +} + +/** + * spi_optimize_message - do any one-time validation and setup for a SPI message + * @spi: the device that will be used for the message + * @msg: the message to optimize + * + * Peripheral drivers that reuse the same message repeatedly may call this to + * perform as much message prep as possible once, rather than repeating it each + * time a message transfer is performed to improve throughput and reduce CPU + * usage. + * + * Once a message has been optimized, it cannot be modified with the exception + * of updating the contents of any xfer->tx_buf (the pointer can't be changed, + * only the data in the memory it points to). + * + * Calls to this function must be balanced with calls to spi_unoptimize_message() + * to avoid leaking resources. + * + * Context: can sleep + * Return: zero on success, else a negative error code + */ +int spi_optimize_message(struct spi_device *spi, struct spi_message *msg) +{ + int ret; + + ret = __spi_optimize_message(spi, msg); + if (ret) + return ret; + + /* + * This flag indicates that the peripheral driver called spi_optimize_message() + * and therefore we shouldn't unoptimize message automatically when finalizing + * the message but rather wait until spi_unoptimize_message() is called + * by the peripheral driver. + */ + msg->pre_optimized = true; + + return 0; +} +EXPORT_SYMBOL_GPL(spi_optimize_message); + +/** + * spi_unoptimize_message - releases any resources allocated by spi_optimize_message() + * @msg: the message to unoptimize + * + * Calls to this function must be balanced with calls to spi_optimize_message(). + * + * Context: can sleep + */ +void spi_unoptimize_message(struct spi_message *msg) +{ + __spi_unoptimize_message(msg); + msg->pre_optimized = false; +} +EXPORT_SYMBOL_GPL(spi_unoptimize_message); + static int __spi_async(struct spi_device *spi, struct spi_message *message) { struct spi_controller *ctlr = spi->controller; @@ -4258,8 +4399,8 @@ int spi_async(struct spi_device *spi, struct spi_message *message) int ret; unsigned long flags; - ret = __spi_validate(spi, message); - if (ret != 0) + ret = spi_maybe_optimize_message(spi, message); + if (ret) return ret; spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags); @@ -4271,6 +4412,8 @@ int spi_async(struct spi_device *spi, struct spi_message *message) spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags); + spi_maybe_unoptimize_message(message); + return ret; } EXPORT_SYMBOL_GPL(spi_async); @@ -4331,8 +4474,8 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) return -ESHUTDOWN; } - status = __spi_validate(spi, message); - if (status != 0) + status = spi_maybe_optimize_message(spi, message); + if (status) return status; SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync); diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 2b8e2746769a..ddfb66dd4caf 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -475,6 +475,8 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * * @set_cs: set the logic level of the chip select line. May be called * from interrupt context. + * @optimize_message: optimize the message for reuse + * @unoptimize_message: release resources allocated by optimize_message * @prepare_message: set up the controller to transfer a single message, * for example doing DMA mapping. Called from threaded * context. @@ -715,6 +717,8 @@ struct spi_controller { struct completion xfer_completion; size_t max_dma_len; + int (*optimize_message)(struct spi_message *msg); + int (*unoptimize_message)(struct spi_message *msg); int (*prepare_transfer_hardware)(struct spi_controller *ctlr); int (*transfer_one_message)(struct spi_controller *ctlr, struct spi_message *mesg); @@ -1111,6 +1115,8 @@ struct spi_transfer { * @spi: SPI device to which the transaction is queued * @is_dma_mapped: if true, the caller provided both DMA and CPU virtual * addresses for each transfer buffer + * @pre_optimized: peripheral driver pre-optimized the message + * @optimized: the message is in the optimized state * @prepared: spi_prepare_message was called for the this message * @status: zero for success, else negative errno * @complete: called to report transaction completions @@ -1120,6 +1126,7 @@ struct spi_transfer { * successful segments * @queue: for use by whichever driver currently owns the message * @state: for use by whichever driver currently owns the message + * @opt_state: for use by whichever driver currently owns the message * @resources: for resource management when the SPI message is processed * * A @spi_message is used to execute an atomic sequence of data transfers, @@ -1143,6 +1150,11 @@ struct spi_message { unsigned is_dma_mapped:1; + /* spi_optimize_message() was called for this message */ + bool pre_optimized; + /* __spi_optimize_message() was called for this message */ + bool optimized; + /* spi_prepare_message() was called for this message */ bool prepared; @@ -1172,6 +1184,11 @@ struct spi_message { */ struct list_head queue; void *state; + /* + * Optional state for use by controller driver between calls to + * __spi_optimize_message() and __spi_unoptimize_message(). + */ + void *opt_state; /* List of spi_res resources when the SPI message is processed */ struct list_head resources; @@ -1255,6 +1272,9 @@ static inline void spi_message_free(struct spi_message *m) kfree(m); } +extern int spi_optimize_message(struct spi_device *spi, struct spi_message *msg); +extern void spi_unoptimize_message(struct spi_message *msg); + extern int spi_setup(struct spi_device *spi); extern int spi_async(struct spi_device *spi, struct spi_message *message); extern int spi_slave_abort(struct spi_device *spi);