Unlike earlier Aspeed SoCs (AST2400/2500/2600) which are limited to
32-bit DMA addressing, the EHCI controller in AST2700 supports 64-bit
DMA. Update the EHCI platform driver to make use of this capability by
selecting a 64-bit DMA mask when the "aspeed,ast2700-ehci" compatible
is present in device tree.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 drivers/usb/host/ehci-platform.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index 6aab45c8525c..18e231d345d0 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -27,6 +27,7 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/sys_soc.h>
@@ -239,6 +240,7 @@ static int ehci_platform_probe(struct platform_device *dev)
 	struct usb_hcd *hcd;
 	struct resource *res_mem;
 	struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
+	const struct of_device_id *match;
 	struct ehci_platform_priv *priv;
 	struct ehci_hcd *ehci;
 	int err, irq, clk = 0;
@@ -253,6 +255,10 @@ static int ehci_platform_probe(struct platform_device *dev)
 	if (!pdata)
 		pdata = &ehci_platform_defaults;
 
+	match = of_match_device(dev->dev.driver->of_match_table, &dev->dev);
+	if (match && match->data)
+		pdata->dma_mask_64 = 1;
+
 	err = dma_coerce_mask_and_coherent(&dev->dev,
 		pdata->dma_mask_64 ? DMA_BIT_MASK(64) : DMA_BIT_MASK(32));
 	if (err) {
@@ -298,7 +304,9 @@ static int ehci_platform_probe(struct platform_device *dev)
 		if (of_device_is_compatible(dev->dev.of_node,
 					    "aspeed,ast2500-ehci") ||
 		    of_device_is_compatible(dev->dev.of_node,
-					    "aspeed,ast2600-ehci"))
+					    "aspeed,ast2600-ehci") ||
+		    of_device_is_compatible(dev->dev.of_node,
+					    "aspeed,ast2700-ehci"))
 			ehci->is_aspeed = 1;
 
 		if (soc_device_match(quirk_poll_match))
@@ -485,6 +493,7 @@ static const struct of_device_id vt8500_ehci_ids[] = {
 	{ .compatible = "wm,prizm-ehci", },
 	{ .compatible = "generic-ehci", },
 	{ .compatible = "cavium,octeon-6335-ehci", },
+	{ .compatible = "aspeed,ast2700-ehci",	.data = (void *)1 },
 	{}
 };
 MODULE_DEVICE_TABLE(of, vt8500_ehci_ids);
-- 
2.34.1

On Fri, Sep 26, 2025 at 10:33:08AM +0800, Ryan Chen wrote:
> Unlike earlier Aspeed SoCs (AST2400/2500/2600) which are limited to
> 32-bit DMA addressing, the EHCI controller in AST2700 supports 64-bit
> DMA. Update the EHCI platform driver to make use of this capability by
> selecting a 64-bit DMA mask when the "aspeed,ast2700-ehci" compatible
> is present in device tree.
> 
> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
> ---
>  drivers/usb/host/ehci-platform.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
> index 6aab45c8525c..18e231d345d0 100644
> --- a/drivers/usb/host/ehci-platform.c
> +++ b/drivers/usb/host/ehci-platform.c
> @@ -27,6 +27,7 @@
>  #include <linux/io.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <linux/platform_device.h>
>  #include <linux/reset.h>
>  #include <linux/sys_soc.h>
> @@ -239,6 +240,7 @@ static int ehci_platform_probe(struct platform_device *dev)
>  	struct usb_hcd *hcd;
>  	struct resource *res_mem;
>  	struct usb_ehci_pdata *pdata = dev_get_platdata(&dev->dev);
> +	const struct of_device_id *match;
>  	struct ehci_platform_priv *priv;
>  	struct ehci_hcd *ehci;
>  	int err, irq, clk = 0;
> @@ -253,6 +255,10 @@ static int ehci_platform_probe(struct platform_device *dev)
>  	if (!pdata)
>  		pdata = &ehci_platform_defaults;
>  
> +	match = of_match_device(dev->dev.driver->of_match_table, &dev->dev);
> +	if (match && match->data)
> +		pdata->dma_mask_64 = 1;

You must not do this, since pdata may be pointing to the static 
ehci_platform_defaults structure.  Instead, set a local variable to the 
value of pdata->dma_mask_64, and if match->data is set then update the 
local variable.  

> +
>  	err = dma_coerce_mask_and_coherent(&dev->dev,
>  		pdata->dma_mask_64 ? DMA_BIT_MASK(64) : DMA_BIT_MASK(32));

Then use the local variable here to select which DMA mask is used.

Alan Stern