diff options
Diffstat (limited to 'drivers/spi/spi-mem.c')
| -rw-r--r-- | drivers/spi/spi-mem.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index abc6792e738c..a9f0f47f4759 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -187,6 +187,16 @@ bool spi_mem_default_supports_op(struct spi_mem *mem, return false; } + if (op->max_freq && mem->spi->controller->min_speed_hz && + op->max_freq < mem->spi->controller->min_speed_hz) + return false; + + if (op->max_freq && + op->max_freq < mem->spi->max_speed_hz) { + if (!spi_mem_controller_is_capable(ctlr, per_op_freq)) + return false; + } + return spi_mem_check_buswidth(mem, op); } EXPORT_SYMBOL_GPL(spi_mem_default_supports_op); @@ -364,6 +374,9 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) u8 *tmpbuf; int ret; + /* Make sure the operation frequency is correct before going futher */ + spi_mem_adjust_op_freq(mem, (struct spi_mem_op *)op); + ret = spi_mem_check_op(op); if (ret) return ret; @@ -410,6 +423,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) xfers[xferpos].tx_buf = tmpbuf; xfers[xferpos].len = op->cmd.nbytes; xfers[xferpos].tx_nbits = op->cmd.buswidth; + xfers[xferpos].speed_hz = op->max_freq; spi_message_add_tail(&xfers[xferpos], &msg); xferpos++; totalxferlen++; @@ -424,6 +438,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) xfers[xferpos].tx_buf = tmpbuf + 1; xfers[xferpos].len = op->addr.nbytes; xfers[xferpos].tx_nbits = op->addr.buswidth; + xfers[xferpos].speed_hz = op->max_freq; spi_message_add_tail(&xfers[xferpos], &msg); xferpos++; totalxferlen += op->addr.nbytes; @@ -435,6 +450,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) xfers[xferpos].len = op->dummy.nbytes; xfers[xferpos].tx_nbits = op->dummy.buswidth; xfers[xferpos].dummy_data = 1; + xfers[xferpos].speed_hz = op->max_freq; spi_message_add_tail(&xfers[xferpos], &msg); xferpos++; totalxferlen += op->dummy.nbytes; @@ -450,6 +466,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) } xfers[xferpos].len = op->data.nbytes; + xfers[xferpos].speed_hz = op->max_freq; spi_message_add_tail(&xfers[xferpos], &msg); xferpos++; totalxferlen += op->data.nbytes; @@ -528,6 +545,53 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op) } EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size); +/** + * spi_mem_adjust_op_freq() - Adjust the frequency of a SPI mem operation to + * match controller, PCB and chip limitations + * @mem: the SPI memory + * @op: the operation to adjust + * + * Some chips have per-op frequency limitations and must adapt the maximum + * speed. This function allows SPI mem drivers to set @op->max_freq to the + * maximum supported value. + */ +void spi_mem_adjust_op_freq(struct spi_mem *mem, struct spi_mem_op *op) +{ + if (!op->max_freq || op->max_freq > mem->spi->max_speed_hz) + op->max_freq = mem->spi->max_speed_hz; +} +EXPORT_SYMBOL_GPL(spi_mem_adjust_op_freq); + +/** + * spi_mem_calc_op_duration() - Derives the theoretical length (in ns) of an + * operation. This helps finding the best variant + * among a list of possible choices. + * @op: the operation to benchmark + * + * Some chips have per-op frequency limitations, PCBs usually have their own + * limitations as well, and controllers can support dual, quad or even octal + * modes, sometimes in DTR. All these combinations make it impossible to + * statically list the best combination for all situations. If we want something + * accurate, all these combinations should be rated (eg. with a time estimate) + * and the best pick should be taken based on these calculations. + * + * Returns a ns estimate for the time this op would take. + */ +u64 spi_mem_calc_op_duration(struct spi_mem_op *op) +{ + u64 ncycles = 0; + u32 ns_per_cycles; + + ns_per_cycles = 1000000000 / op->max_freq; + ncycles += ((op->cmd.nbytes * 8) / op->cmd.buswidth) / (op->cmd.dtr ? 2 : 1); + ncycles += ((op->addr.nbytes * 8) / op->addr.buswidth) / (op->addr.dtr ? 2 : 1); + ncycles += ((op->dummy.nbytes * 8) / op->dummy.buswidth) / (op->dummy.dtr ? 2 : 1); + ncycles += ((op->data.nbytes * 8) / op->data.buswidth) / (op->data.dtr ? 2 : 1); + + return ncycles * ns_per_cycles; +} +EXPORT_SYMBOL_GPL(spi_mem_calc_op_duration); + static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, void *buf) { |