diff mbox series

[v3,4/9] spi: cadence-qspi: allow FIFO depth detection

Message ID 20240410-cdns-qspi-mbly-v3-4-7b7053449cf7@bootlin.com (mailing list archive)
State Superseded
Headers show
Series spi: cadence-qspi: add Mobileye EyeQ5 support | expand

Commit Message

Théo Lebrun April 10, 2024, 9:29 a.m. UTC
If FIFO depth DT property is provided, check it matches what hardware
reports and warn otherwise. Else, use hardware provided value.

Hardware exposes FIFO depth indirectly because
CQSPI_REG_SRAMPARTITION is partially read-only.

Move probe cqspi->ddata assignment prior to cqspi_of_get_pdata() call.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/spi/spi-cadence-quadspi.c | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

Comments

Mark Brown April 10, 2024, 8:03 p.m. UTC | #1
On Wed, Apr 10, 2024 at 11:29:07AM +0200, Théo Lebrun wrote:

> If FIFO depth DT property is provided, check it matches what hardware
> reports and warn otherwise. Else, use hardware provided value.
> 
> Hardware exposes FIFO depth indirectly because
> CQSPI_REG_SRAMPARTITION is partially read-only.

This breaks an allmodconfig build:

/build/stage/linux/drivers/spi/spi-cadence-quadspi.c: In function ‘cqspi_of_get_
pdata’:
/build/stage/linux/drivers/spi/spi-cadence-quadspi.c:1506:45: error: unused vari
able ‘ddata’ [-Werror=unused-variable]
 1506 |         const struct cqspi_driver_platdata *ddata = cqspi->ddata;
      |                                             ^~~~~
/build/stage/linux/drivers/spi/spi-cadence-quadspi.c: In function ‘cqspi_control
ler_detect_fifo_depth’:
/build/stage/linux/drivers/spi/spi-cadence-quadspi.c:1582:45: error: unused vari
able ‘ddata’ [-Werror=unused-variable]
 1582 |         const struct cqspi_driver_platdata *ddata = cqspi->ddata;
      |                                             ^~~~~
cc1: all warnings being treated as errors
Théo Lebrun April 11, 2024, 9:27 a.m. UTC | #2
Hello,

On Wed Apr 10, 2024 at 10:03 PM CEST, Mark Brown wrote:
> On Wed, Apr 10, 2024 at 11:29:07AM +0200, Théo Lebrun wrote:
>
> > If FIFO depth DT property is provided, check it matches what hardware
> > reports and warn otherwise. Else, use hardware provided value.
> > 
> > Hardware exposes FIFO depth indirectly because
> > CQSPI_REG_SRAMPARTITION is partially read-only.
>
> This breaks an allmodconfig build:
>
> /build/stage/linux/drivers/spi/spi-cadence-quadspi.c: In function ‘cqspi_of_get_
> pdata’:
> /build/stage/linux/drivers/spi/spi-cadence-quadspi.c:1506:45: error: unused vari
> able ‘ddata’ [-Werror=unused-variable]
>  1506 |         const struct cqspi_driver_platdata *ddata = cqspi->ddata;
>       |                                             ^~~~~
> /build/stage/linux/drivers/spi/spi-cadence-quadspi.c: In function ‘cqspi_control
> ler_detect_fifo_depth’:
> /build/stage/linux/drivers/spi/spi-cadence-quadspi.c:1582:45: error: unused vari
> able ‘ddata’ [-Werror=unused-variable]
>  1582 |         const struct cqspi_driver_platdata *ddata = cqspi->ddata;
>       |                                             ^~~~~
> cc1: all warnings being treated as errors

I really should fix my kernel compiler warnings. Sorry about that.
Will fix next revision.

Regards,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
diff mbox series

Patch

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 9896e9fe7ffb..b499f2e5ec87 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1503,6 +1503,7 @@  static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
 
 static int cqspi_of_get_pdata(struct cqspi_st *cqspi)
 {
+	const struct cqspi_driver_platdata *ddata = cqspi->ddata;
 	struct device *dev = &cqspi->pdev->dev;
 	struct device_node *np = dev->of_node;
 	u32 id[2];
@@ -1510,8 +1511,8 @@  static int cqspi_of_get_pdata(struct cqspi_st *cqspi)
 	cqspi->is_decoded_cs = of_property_read_bool(np, "cdns,is-decoded-cs");
 
 	if (of_property_read_u32(np, "cdns,fifo-depth", &cqspi->fifo_depth)) {
-		dev_err(dev, "couldn't determine fifo-depth\n");
-		return -ENXIO;
+		/* Zero signals FIFO depth should be runtime detected. */
+		cqspi->fifo_depth = 0;
 	}
 
 	if (of_property_read_u32(np, "cdns,fifo-width", &cqspi->fifo_width)) {
@@ -1541,8 +1542,6 @@  static void cqspi_controller_init(struct cqspi_st *cqspi)
 {
 	u32 reg;
 
-	cqspi_controller_enable(cqspi, 0);
-
 	/* Configure the remap address register, no remap */
 	writel(0, cqspi->iobase + CQSPI_REG_REMAP);
 
@@ -1576,8 +1575,30 @@  static void cqspi_controller_init(struct cqspi_st *cqspi)
 		reg |= CQSPI_REG_CONFIG_DMA_MASK;
 		writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
 	}
+}
 
-	cqspi_controller_enable(cqspi, 1);
+static void cqspi_controller_detect_fifo_depth(struct cqspi_st *cqspi)
+{
+	const struct cqspi_driver_platdata *ddata = cqspi->ddata;
+	struct device *dev = &cqspi->pdev->dev;
+	u32 reg, fifo_depth;
+
+	/*
+	 * Bits N-1:0 are writable while bits 31:N are read as zero, with 2^N
+	 * the FIFO depth.
+	 */
+	writel(U32_MAX, cqspi->iobase + CQSPI_REG_SRAMPARTITION);
+	reg = readl(cqspi->iobase + CQSPI_REG_SRAMPARTITION);
+	fifo_depth = reg + 1;
+
+	/* FIFO depth of zero means no value from devicetree was provided. */
+	if (cqspi->fifo_depth == 0) {
+		cqspi->fifo_depth = fifo_depth;
+		dev_dbg(dev, "using FIFO depth of %u\n", fifo_depth);
+	} else if (fifo_depth != cqspi->fifo_depth) {
+		dev_warn(dev, "detected FIFO depth (%u) different from config (%u)\n",
+			 fifo_depth, cqspi->fifo_depth);
+	}
 }
 
 static int cqspi_request_mmap_dma(struct cqspi_st *cqspi)
@@ -1730,6 +1751,7 @@  static int cqspi_probe(struct platform_device *pdev)
 	cqspi->pdev = pdev;
 	cqspi->host = host;
 	cqspi->is_jh7110 = false;
+	cqspi->ddata = ddata = of_device_get_match_data(dev);
 	platform_set_drvdata(pdev, cqspi);
 
 	/* Obtain configuration from OF. */
@@ -1821,8 +1843,6 @@  static int cqspi_probe(struct platform_device *pdev)
 	/* write completion is supported by default */
 	cqspi->wr_completion = true;
 
-	ddata = of_device_get_match_data(dev);
-	cqspi->ddata = ddata;
 	if (ddata) {
 		if (ddata->quirks & CQSPI_NEEDS_WR_DELAY)
 			cqspi->wr_delay = 50 * DIV_ROUND_UP(NSEC_PER_SEC,
@@ -1864,7 +1884,10 @@  static int cqspi_probe(struct platform_device *pdev)
 	}
 
 	cqspi_wait_idle(cqspi);
+	cqspi_controller_enable(cqspi, 0);
+	cqspi_controller_detect_fifo_depth(cqspi);
 	cqspi_controller_init(cqspi);
+	cqspi_controller_enable(cqspi, 1);
 	cqspi->current_cs = -1;
 	cqspi->sclk = 0;
 
@@ -1947,7 +1970,9 @@  static int cqspi_runtime_resume(struct device *dev)
 
 	clk_prepare_enable(cqspi->clk);
 	cqspi_wait_idle(cqspi);
+	cqspi_controller_enable(cqspi, 0);
 	cqspi_controller_init(cqspi);
+	cqspi_controller_enable(cqspi, 1);
 
 	cqspi->current_cs = -1;
 	cqspi->sclk = 0;