From cdf61240e11f838705b7a3f51acad5b641e54210 Mon Sep 17 00:00:00 2001 From: Kishon Vijay Abraham I Date: Tue, 17 Mar 2015 16:54:51 +0530 Subject: bus: ocp2scp: SYNC2 value should be changed to 0x6 As per the TRMs of AM572x, OMAP4430, OMAP4460, OMAP543x, the value of SYNC2 must be set to 0x6 in order to ensure correct operation. So modified the SYNC2 value of OCP2SCP TIMING register to 0x6 in all the platforms that use OCP2SCP driver except AM437x. Also introduced a new compatible property since we don't want to modify the OCP2SCP TIMING register for AM437x. The sections in TRM where the above caution can be found is mentioned below. AM572x TRM SPRUHZ6 (http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf) under section 26.3.2.2, table 26-26. OMAP4430 TRM SWPU231AP (http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf) under section 23.12.6.2.2 , Table 23-1213. OMAP4460 TRM SWPU235AB (http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf) under section 23.12.6.2.2, Table 23-1213. OMAP543x TRM SWPU249 (http://www.ti.com/lit/pdf/swpu249) under section 27.3.2.2, Table 27-27. Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Signed-off-by: Kishon Vijay Abraham I Signed-off-by: Praneeth Bajjuri Signed-off-by: Tony Lindgren --- drivers/bus/omap-ocp2scp.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'drivers/bus') diff --git a/drivers/bus/omap-ocp2scp.c b/drivers/bus/omap-ocp2scp.c index 723ec06ad2c8..9f1856948758 100644 --- a/drivers/bus/omap-ocp2scp.c +++ b/drivers/bus/omap-ocp2scp.c @@ -16,6 +16,7 @@ * */ +#include #include #include #include @@ -23,6 +24,9 @@ #include #include +#define OCP2SCP_TIMING 0x18 +#define SYNC2_MASK 0xf + static int ocp2scp_remove_devices(struct device *dev, void *c) { struct platform_device *pdev = to_platform_device(dev); @@ -35,6 +39,9 @@ static int ocp2scp_remove_devices(struct device *dev, void *c) static int omap_ocp2scp_probe(struct platform_device *pdev) { int ret; + u32 reg; + void __iomem *regs; + struct resource *res; struct device_node *np = pdev->dev.of_node; if (np) { @@ -47,6 +54,32 @@ static int omap_ocp2scp_probe(struct platform_device *pdev) } pm_runtime_enable(&pdev->dev); + /* + * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf + * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution; + * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf + * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution; + * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf + * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution; + * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249 + * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution; + * + * Read path of OCP2SCP is not working properly due to low reset value + * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more. + */ + if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) { + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(regs)) + goto err0; + + pm_runtime_get_sync(&pdev->dev); + reg = readl_relaxed(regs + OCP2SCP_TIMING); + reg &= ~(SYNC2_MASK); + reg |= 0x6; + writel_relaxed(reg, regs + OCP2SCP_TIMING); + pm_runtime_put_sync(&pdev->dev); + } return 0; @@ -67,6 +100,7 @@ static int omap_ocp2scp_remove(struct platform_device *pdev) #ifdef CONFIG_OF static const struct of_device_id omap_ocp2scp_id_table[] = { { .compatible = "ti,omap-ocp2scp" }, + { .compatible = "ti,am437x-ocp2scp" }, {} }; MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table); -- cgit v1.2.3