From 1f257b92e6330d576cc826fb8f0b74fe0e8209de Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Th=C3=A9o=20Lebrun?= Date: Tue, 23 Apr 2024 12:01:41 +0200 Subject: spi: cadence-qspi: add no-IRQ mode to indirect reads MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Support reads through polling, without any IRQ. The main reason is performance; profiling shows that the first IRQ comes quickly on our specific hardware. Once this IRQ arrives, we poll until all data is retrieved. Avoid initial sleep to reduce IRQ count. Hide this behavior behind a quirk flag. This is confirmed through micro-benchmarks, but also end-to-end performance tests. Mobileye EyeQ5, octal flash, reading 235M on a UBIFS filesystem: - No optimizations, ~10.34s, ~22.7 MB/s, 199230 IRQs - CQSPI_SLOW_SRAM, ~10.34s, ~22.7 MB/s, 70284 IRQs - CQSPI_RD_NO_IRQ, ~9.37s, ~25.1 MB/s, 521 IRQs Signed-off-by: Théo Lebrun Link: https://lore.kernel.org/r/20240423-cdns-qspi-mbly-v4-2-3d2a7b535ad0@bootlin.com Signed-off-by: Mark Brown --- drivers/spi/spi-cadence-quadspi.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index 5a83940220a9..a82e23526a6f 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -42,6 +42,7 @@ static_assert(CQSPI_MAX_CHIPSELECT <= SPI_CS_CNT_MAX); #define CQSPI_NO_SUPPORT_WR_COMPLETION BIT(3) #define CQSPI_SLOW_SRAM BIT(4) #define CQSPI_NEEDS_APB_AHB_HAZARD_WAR BIT(5) +#define CQSPI_RD_NO_IRQ BIT(6) /* Capabilities */ #define CQSPI_SUPPORTS_OCTAL BIT(0) @@ -702,6 +703,7 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, const size_t n_rx) { struct cqspi_st *cqspi = f_pdata->cqspi; + bool use_irq = !(cqspi->ddata && cqspi->ddata->quirks & CQSPI_RD_NO_IRQ); struct device *dev = &cqspi->pdev->dev; void __iomem *reg_base = cqspi->iobase; void __iomem *ahb_base = cqspi->ahb_base; @@ -725,17 +727,20 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, * all the read interrupts disabled for max performance. */ - if (!cqspi->slow_sram) + if (use_irq && cqspi->slow_sram) + writel(CQSPI_REG_IRQ_WATERMARK, reg_base + CQSPI_REG_IRQMASK); + else if (use_irq) writel(CQSPI_IRQ_MASK_RD, reg_base + CQSPI_REG_IRQMASK); else - writel(CQSPI_REG_IRQ_WATERMARK, reg_base + CQSPI_REG_IRQMASK); + writel(0, reg_base + CQSPI_REG_IRQMASK); reinit_completion(&cqspi->transfer_complete); writel(CQSPI_REG_INDIRECTRD_START_MASK, reg_base + CQSPI_REG_INDIRECTRD); while (remaining > 0) { - if (!wait_for_completion_timeout(&cqspi->transfer_complete, + if (use_irq && + !wait_for_completion_timeout(&cqspi->transfer_complete, msecs_to_jiffies(CQSPI_READ_TIMEOUT_MS))) ret = -ETIMEDOUT; @@ -777,7 +782,7 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, bytes_to_read = cqspi_get_rd_sram_level(cqspi); } - if (remaining > 0) { + if (use_irq && remaining > 0) { reinit_completion(&cqspi->transfer_complete); if (cqspi->slow_sram) writel(CQSPI_REG_IRQ_WATERMARK, reg_base + CQSPI_REG_IRQMASK); -- cgit v1.2.3