diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 518 |
1 files changed, 308 insertions, 210 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index a7194f29c2..c349d60126 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -459,7 +459,7 @@ static void spi_shutdown(struct device *dev) } } -struct bus_type spi_bus_type = { +const struct bus_type spi_bus_type = { .name = "spi", .dev_groups = spi_dev_groups, .match = spi_match_device, @@ -584,7 +584,7 @@ struct spi_device *spi_alloc_device(struct spi_controller *ctlr) return NULL; } - spi->master = spi->controller = ctlr; + spi->controller = ctlr; spi->dev.parent = &ctlr->dev; spi->dev.bus = &spi_bus_type; spi->dev.release = spidev_release; @@ -608,23 +608,51 @@ static void spi_dev_set_name(struct spi_device *spi) spi_get_chipselect(spi, 0)); } +/* + * Zero(0) is a valid physical CS value and can be located at any + * logical CS in the spi->chip_select[]. If all the physical CS + * are initialized to 0 then It would be difficult to differentiate + * between a valid physical CS 0 & an unused logical CS whose physical + * CS can be 0. As a solution to this issue initialize all the CS to -1. + * Now all the unused logical CS will have -1 physical CS value & can be + * ignored while performing physical CS validity checks. + */ +#define SPI_INVALID_CS ((s8)-1) + +static inline bool is_valid_cs(s8 chip_select) +{ + return chip_select != SPI_INVALID_CS; +} + +static inline int spi_dev_check_cs(struct device *dev, + struct spi_device *spi, u8 idx, + struct spi_device *new_spi, u8 new_idx) +{ + u8 cs, cs_new; + u8 idx_new; + + cs = spi_get_chipselect(spi, idx); + for (idx_new = new_idx; idx_new < SPI_CS_CNT_MAX; idx_new++) { + cs_new = spi_get_chipselect(new_spi, idx_new); + if (is_valid_cs(cs) && is_valid_cs(cs_new) && cs == cs_new) { + dev_err(dev, "chipselect %u already in use\n", cs_new); + return -EBUSY; + } + } + return 0; +} + static int spi_dev_check(struct device *dev, void *data) { struct spi_device *spi = to_spi_device(dev); struct spi_device *new_spi = data; - int idx, nw_idx; - u8 cs, cs_nw; + int status, idx; if (spi->controller == new_spi->controller) { for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { - cs = spi_get_chipselect(spi, idx); - for (nw_idx = 0; nw_idx < SPI_CS_CNT_MAX; nw_idx++) { - cs_nw = spi_get_chipselect(new_spi, nw_idx); - if (cs != 0xFF && cs_nw != 0xFF && cs == cs_nw) { - dev_err(dev, "chipselect %d already in use\n", cs_nw); - return -EBUSY; - } - } + status = spi_dev_check_cs(dev, spi, idx, new_spi, 0); + if (status) + return status; } } return 0; @@ -640,13 +668,13 @@ static int __spi_add_device(struct spi_device *spi) { struct spi_controller *ctlr = spi->controller; struct device *dev = ctlr->dev.parent; - int status, idx, nw_idx; - u8 cs, nw_cs; + int status, idx; + u8 cs; for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { /* Chipselects are numbered 0..max; validate. */ cs = spi_get_chipselect(spi, idx); - if (cs != 0xFF && cs >= ctlr->num_chipselect) { + if (is_valid_cs(cs) && cs >= ctlr->num_chipselect) { dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx), ctlr->num_chipselect); return -EINVAL; @@ -657,14 +685,11 @@ static int __spi_add_device(struct spi_device *spi) * Make sure that multiple logical CS doesn't map to the same physical CS. * For example, spi->chip_select[0] != spi->chip_select[1] and so on. */ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { - cs = spi_get_chipselect(spi, idx); - for (nw_idx = idx + 1; nw_idx < SPI_CS_CNT_MAX; nw_idx++) { - nw_cs = spi_get_chipselect(spi, nw_idx); - if (cs != 0xFF && nw_cs != 0xFF && cs == nw_cs) { - dev_err(dev, "chipselect %d already in use\n", nw_cs); - return -EBUSY; - } + if (!spi_controller_is_target(ctlr)) { + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + status = spi_dev_check_cs(dev, spi, idx, spi, idx + 1); + if (status) + return status; } } @@ -691,7 +716,7 @@ static int __spi_add_device(struct spi_device *spi) for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { cs = spi_get_chipselect(spi, idx); - if (cs != 0xFF) + if (is_valid_cs(cs)) spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]); } } @@ -745,6 +770,14 @@ int spi_add_device(struct spi_device *spi) } EXPORT_SYMBOL_GPL(spi_add_device); +static void spi_set_all_cs_unused(struct spi_device *spi) +{ + u8 idx; + + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) + spi_set_chipselect(spi, idx, SPI_INVALID_CS); +} + /** * spi_new_device - instantiate one new SPI device * @ctlr: Controller to which device is connected @@ -764,7 +797,6 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr, { struct spi_device *proxy; int status; - u8 idx; /* * NOTE: caller did any chip->bus_num checks necessary. @@ -780,19 +812,10 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr, WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias)); - /* - * Zero(0) is a valid physical CS value and can be located at any - * logical CS in the spi->chip_select[]. If all the physical CS - * are initialized to 0 then It would be difficult to differentiate - * between a valid physical CS 0 & an unused logical CS whose physical - * CS can be 0. As a solution to this issue initialize all the CS to 0xFF. - * Now all the unused logical CS will have 0xFF physical CS value & can be - * ignore while performing physical CS validity checks. - */ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - spi_set_chipselect(proxy, idx, 0xFF); - + /* Use provided chip-select for proxy device */ + spi_set_all_cs_unused(proxy); spi_set_chipselect(proxy, 0, chip->chip_select); + proxy->max_speed_hz = chip->max_speed_hz; proxy->mode = chip->mode; proxy->irq = chip->irq; @@ -1007,7 +1030,7 @@ static inline bool spi_is_last_cs(struct spi_device *spi) bool last = false; for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { - if ((spi->cs_index_mask >> idx) & 0x01) { + if (spi->cs_index_mask & BIT(idx)) { if (spi->controller->last_cs[idx] == spi_get_chipselect(spi, idx)) last = true; } @@ -1036,7 +1059,7 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force) spi->controller->last_cs_index_mask = spi->cs_index_mask; for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - spi->controller->last_cs[idx] = enable ? spi_get_chipselect(spi, 0) : -1; + spi->controller->last_cs[idx] = enable ? spi_get_chipselect(spi, 0) : SPI_INVALID_CS; spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH; if (spi->mode & SPI_CS_HIGH) @@ -1062,8 +1085,7 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force) * into account. */ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { - if (((spi->cs_index_mask >> idx) & 0x01) && - spi_get_csgpiod(spi, idx)) { + if ((spi->cs_index_mask & BIT(idx)) && spi_get_csgpiod(spi, idx)) { if (has_acpi_companion(&spi->dev)) gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx), !enable); @@ -1222,6 +1244,7 @@ static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) else rx_dev = ctlr->dev.parent; + ret = -ENOMSG; list_for_each_entry(xfer, &msg->transfers, transfer_list) { /* The sync is done before each transfer. */ unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC; @@ -1251,6 +1274,9 @@ static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg) } } } + /* No transfer has been mapped, bail out with success */ + if (ret) + return 0; ctlr->cur_rx_dma_dev = rx_dev; ctlr->cur_tx_dma_dev = tx_dev; @@ -1751,39 +1777,6 @@ static int __spi_pump_transfer_message(struct spi_controller *ctlr, trace_spi_message_start(msg); - /* - * If an SPI controller does not support toggling the CS line on each - * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO - * for the CS line, we can emulate the CS-per-word hardware function by - * splitting transfers into one-word transfers and ensuring that - * cs_change is set for each transfer. - */ - if ((msg->spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) || - spi_is_csgpiod(msg->spi))) { - ret = spi_split_transfers_maxwords(ctlr, msg, 1, GFP_KERNEL); - if (ret) { - msg->status = ret; - spi_finalize_current_message(ctlr); - return ret; - } - - list_for_each_entry(xfer, &msg->transfers, transfer_list) { - /* Don't change cs_change on the last entry in the list */ - if (list_is_last(&xfer->transfer_list, &msg->transfers)) - break; - xfer->cs_change = 1; - } - } else { - ret = spi_split_transfers_maxsize(ctlr, msg, - spi_max_transfer_size(msg->spi), - GFP_KERNEL | GFP_DMA); - if (ret) { - msg->status = ret; - spi_finalize_current_message(ctlr); - return ret; - } - } - if (ctlr->prepare_message) { ret = ctlr->prepare_message(ctlr, msg); if (ret) { @@ -2111,6 +2104,43 @@ 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); + + spi_res_release(ctlr, 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 @@ -2139,15 +2169,6 @@ void spi_finalize_current_message(struct spi_controller *ctlr) spi_unmap_msg(ctlr, mesg); - /* - * In the prepare_messages callback the SPI bus has the opportunity - * to split a transfer to smaller chunks. - * - * Release the split transfers here since spi_map_msg() is done on - * the split transfers. - */ - spi_res_release(ctlr, mesg); - if (mesg->prepared && ctlr->unprepare_message) { ret = ctlr->unprepare_message(ctlr, mesg); if (ret) { @@ -2158,6 +2179,8 @@ 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)) @@ -2425,17 +2448,7 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, return -EINVAL; } - /* - * Zero(0) is a valid physical CS value and can be located at any - * logical CS in the spi->chip_select[]. If all the physical CS - * are initialized to 0 then It would be difficult to differentiate - * between a valid physical CS 0 & an unused logical CS whose physical - * CS can be 0. As a solution to this issue initialize all the CS to 0xFF. - * Now all the unused logical CS will have 0xFF physical CS value & can be - * ignore while performing physical CS validity checks. - */ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - spi_set_chipselect(spi, idx, 0xFF); + spi_set_all_cs_unused(spi); /* Device address */ rc = of_property_read_variable_u32_array(nc, "reg", &cs[0], 1, @@ -2459,14 +2472,10 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, spi_set_chipselect(spi, idx, cs[idx]); /* - * spi->chip_select[i] gives the corresponding physical CS for logical CS i - * logical CS number is represented by setting the ith bit in spi->cs_index_mask - * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and - * spi->chip_select[0] will give the physical CS. - * By default spi->chip_select[0] will hold the physical CS number so, set - * spi->cs_index_mask as 0x01. + * By default spi->chip_select[0] will hold the physical CS number, + * so set bit 0 in spi->cs_index_mask. */ - spi->cs_index_mask = 0x01; + spi->cs_index_mask = BIT(0); /* Device speed */ if (!of_property_read_u32(nc, "spi-max-frequency", &value)) @@ -2572,7 +2581,6 @@ struct spi_device *spi_new_ancillary_device(struct spi_device *spi, struct spi_controller *ctlr = spi->controller; struct spi_device *ancillary; int rc = 0; - u8 idx; /* Alloc an spi_device */ ancillary = spi_alloc_device(ctlr); @@ -2583,33 +2591,18 @@ struct spi_device *spi_new_ancillary_device(struct spi_device *spi, strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias)); - /* - * Zero(0) is a valid physical CS value and can be located at any - * logical CS in the spi->chip_select[]. If all the physical CS - * are initialized to 0 then It would be difficult to differentiate - * between a valid physical CS 0 & an unused logical CS whose physical - * CS can be 0. As a solution to this issue initialize all the CS to 0xFF. - * Now all the unused logical CS will have 0xFF physical CS value & can be - * ignore while performing physical CS validity checks. - */ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - spi_set_chipselect(ancillary, idx, 0xFF); - /* Use provided chip-select for ancillary device */ + spi_set_all_cs_unused(ancillary); spi_set_chipselect(ancillary, 0, chip_select); /* Take over SPI mode/speed from SPI main device */ ancillary->max_speed_hz = spi->max_speed_hz; ancillary->mode = spi->mode; /* - * spi->chip_select[i] gives the corresponding physical CS for logical CS i - * logical CS number is represented by setting the ith bit in spi->cs_index_mask - * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and - * spi->chip_select[0] will give the physical CS. - * By default spi->chip_select[0] will hold the physical CS number so, set - * spi->cs_index_mask as 0x01. + * By default spi->chip_select[0] will hold the physical CS number, + * so set bit 0 in spi->cs_index_mask. */ - ancillary->cs_index_mask = 0x01; + ancillary->cs_index_mask = BIT(0); WARN_ON(!mutex_is_locked(&ctlr->add_lock)); @@ -2812,7 +2805,6 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, struct acpi_spi_lookup lookup = {}; struct spi_device *spi; int ret; - u8 idx; if (!ctlr && index == -1) return ERR_PTR(-EINVAL); @@ -2848,33 +2840,19 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr, return ERR_PTR(-ENOMEM); } - /* - * Zero(0) is a valid physical CS value and can be located at any - * logical CS in the spi->chip_select[]. If all the physical CS - * are initialized to 0 then It would be difficult to differentiate - * between a valid physical CS 0 & an unused logical CS whose physical - * CS can be 0. As a solution to this issue initialize all the CS to 0xFF. - * Now all the unused logical CS will have 0xFF physical CS value & can be - * ignore while performing physical CS validity checks. - */ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - spi_set_chipselect(spi, idx, 0xFF); + spi_set_all_cs_unused(spi); + spi_set_chipselect(spi, 0, lookup.chip_select); ACPI_COMPANION_SET(&spi->dev, adev); spi->max_speed_hz = lookup.max_speed_hz; spi->mode |= lookup.mode; spi->irq = lookup.irq; spi->bits_per_word = lookup.bits_per_word; - spi_set_chipselect(spi, 0, lookup.chip_select); /* - * spi->chip_select[i] gives the corresponding physical CS for logical CS i - * logical CS number is represented by setting the ith bit in spi->cs_index_mask - * So, for example, if spi->cs_index_mask = 0x01 then logical CS number is 0 and - * spi->chip_select[0] will give the physical CS. - * By default spi->chip_select[0] will hold the physical CS number so, set - * spi->cs_index_mask as 0x01. + * By default spi->chip_select[0] will hold the physical CS number, + * so set bit 0 in spi->cs_index_mask. */ - spi->cs_index_mask = 0x01; + spi->cs_index_mask = BIT(0); return spi; } @@ -3372,9 +3350,9 @@ int spi_register_controller(struct spi_controller *ctlr) goto free_bus_id; } - /* Setting last_cs to -1 means no chip selected */ + /* Setting last_cs to SPI_INVALID_CS means no chip selected */ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) - ctlr->last_cs[idx] = -1; + ctlr->last_cs[idx] = SPI_INVALID_CS; status = device_add(&ctlr->dev); if (status < 0) @@ -3715,8 +3693,7 @@ static struct spi_replaced_transfers *spi_replace_transfers( static int __spi_split_transfer_maxsize(struct spi_controller *ctlr, struct spi_message *msg, struct spi_transfer **xferp, - size_t maxsize, - gfp_t gfp) + size_t maxsize) { struct spi_transfer *xfer = *xferp, *xfers; struct spi_replaced_transfers *srt; @@ -3727,7 +3704,7 @@ static int __spi_split_transfer_maxsize(struct spi_controller *ctlr, count = DIV_ROUND_UP(xfer->len, maxsize); /* Create replacement */ - srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp); + srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, GFP_KERNEL); if (IS_ERR(srt)) return PTR_ERR(srt); xfers = srt->inserted_transfers; @@ -3787,14 +3764,16 @@ static int __spi_split_transfer_maxsize(struct spi_controller *ctlr, * @ctlr: the @spi_controller for this transfer * @msg: the @spi_message to transform * @maxsize: the maximum when to apply this - * @gfp: GFP allocation flags + * + * This function allocates resources that are automatically freed during the + * spi message unoptimize phase so this function should only be called from + * optimize_message callbacks. * * Return: status of transformation */ int spi_split_transfers_maxsize(struct spi_controller *ctlr, struct spi_message *msg, - size_t maxsize, - gfp_t gfp) + size_t maxsize) { struct spi_transfer *xfer; int ret; @@ -3809,7 +3788,7 @@ int spi_split_transfers_maxsize(struct spi_controller *ctlr, list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (xfer->len > maxsize) { ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer, - maxsize, gfp); + maxsize); if (ret) return ret; } @@ -3827,14 +3806,16 @@ EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize); * @ctlr: the @spi_controller for this transfer * @msg: the @spi_message to transform * @maxwords: the number of words to limit each transfer to - * @gfp: GFP allocation flags + * + * This function allocates resources that are automatically freed during the + * spi message unoptimize phase so this function should only be called from + * optimize_message callbacks. * * Return: status of transformation */ int spi_split_transfers_maxwords(struct spi_controller *ctlr, struct spi_message *msg, - size_t maxwords, - gfp_t gfp) + size_t maxwords) { struct spi_transfer *xfer; @@ -3852,7 +3833,7 @@ int spi_split_transfers_maxwords(struct spi_controller *ctlr, maxsize = maxwords * roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word)); if (xfer->len > maxsize) { ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer, - maxsize, gfp); + maxsize); if (ret) return ret; } @@ -4204,6 +4185,167 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) return 0; } +/* + * spi_split_transfers - generic handling of transfer splitting + * @msg: the message to split + * + * Under certain conditions, a SPI controller may not support arbitrary + * transfer sizes or other features required by a peripheral. This function + * will split the transfers in the message into smaller transfers that are + * supported by the controller. + * + * Controllers with special requirements not covered here can also split + * transfers in the optimize_message() callback. + * + * Context: can sleep + * Return: zero on success, else a negative error code + */ +static int spi_split_transfers(struct spi_message *msg) +{ + struct spi_controller *ctlr = msg->spi->controller; + struct spi_transfer *xfer; + int ret; + + /* + * If an SPI controller does not support toggling the CS line on each + * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO + * for the CS line, we can emulate the CS-per-word hardware function by + * splitting transfers into one-word transfers and ensuring that + * cs_change is set for each transfer. + */ + if ((msg->spi->mode & SPI_CS_WORD) && + (!(ctlr->mode_bits & SPI_CS_WORD) || spi_is_csgpiod(msg->spi))) { + ret = spi_split_transfers_maxwords(ctlr, msg, 1); + if (ret) + return ret; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + /* Don't change cs_change on the last entry in the list */ + if (list_is_last(&xfer->transfer_list, &msg->transfers)) + break; + + xfer->cs_change = 1; + } + } else { + ret = spi_split_transfers_maxsize(ctlr, msg, + spi_max_transfer_size(msg->spi)); + if (ret) + return ret; + } + + 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; + + ret = spi_split_transfers(msg); + if (ret) + return ret; + + if (ctlr->optimize_message) { + ret = ctlr->optimize_message(msg); + if (ret) { + spi_res_release(ctlr, msg); + 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; @@ -4268,8 +4410,8 @@ 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); @@ -4281,60 +4423,11 @@ int spi_async(struct spi_device *spi, struct spi_message *message) spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags); - return ret; -} -EXPORT_SYMBOL_GPL(spi_async); - -/** - * spi_async_locked - version of spi_async with exclusive bus usage - * @spi: device with which data will be exchanged - * @message: describes the data transfers, including completion callback - * Context: any (IRQs may be blocked, etc) - * - * This call may be used in_irq and other contexts which can't sleep, - * as well as from task contexts which can sleep. - * - * The completion callback is invoked in a context which can't sleep. - * Before that invocation, the value of message->status is undefined. - * When the callback is issued, message->status holds either zero (to - * indicate complete success) or a negative error code. After that - * callback returns, the driver which issued the transfer request may - * deallocate the associated memory; it's no longer in use by any SPI - * core or controller driver code. - * - * Note that although all messages to a spi_device are handled in - * FIFO order, messages may go to different devices in other orders. - * Some device might be higher priority, or have various "hard" access - * time requirements, for example. - * - * On detection of any fault during the transfer, processing of - * the entire message is aborted, and the device is deselected. - * Until returning from the associated message completion callback, - * no other spi_message queued to that device will be processed. - * (This rule applies equally to all the synchronous transfer calls, - * which are wrappers around this core asynchronous primitive.) - * - * Return: zero on success, else a negative error code. - */ -static int spi_async_locked(struct spi_device *spi, struct spi_message *message) -{ - struct spi_controller *ctlr = spi->controller; - int ret; - unsigned long flags; - - ret = __spi_validate(spi, message); - if (ret != 0) - return ret; - - spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags); - - ret = __spi_async(spi, message); - - spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags); + spi_maybe_unoptimize_message(message); return ret; - } +EXPORT_SYMBOL_GPL(spi_async); static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg) { @@ -4383,6 +4476,7 @@ static void spi_complete(void *arg) static int __spi_sync(struct spi_device *spi, struct spi_message *message) { DECLARE_COMPLETION_ONSTACK(done); + unsigned long flags; int status; struct spi_controller *ctlr = spi->controller; @@ -4391,8 +4485,8 @@ 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); @@ -4426,7 +4520,11 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) */ message->complete = spi_complete; message->context = &done; - status = spi_async_locked(spi, message); + + spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags); + status = __spi_async(spi, message); + spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags); + if (status == 0) { wait_for_completion(&done); status = message->status; |