Changes in V8:
- Rebased to usb-testing
- Using devm_kzalloc for adding txfifo property in dwc3-qcom
- Removed DWC3 QCOM ACPI property for enabling the txfifo resize
Changes in V7:
- Added a new property tx-fifo-max-num for limiting how much fifo space the
resizing logic can allocate for endpoints with large burst values. This
can differ across platforms, and tie in closely with overall system latency.
- Added recommended checks for DWC32.
- Added changes to set the tx-fifo-resize property from dwc3-qcom by default
instead of modifying the current DTSI files.
- Added comments on all APIs/variables introduced.
- Updated the DWC3 YAML to include a better description of the tx-fifo-resize
property and added an entry for tx-fifo-max-num.
Changes in V6:
- Rebased patches to usb-testing.
- Renamed to PATCH series instead of RFC.
- Checking for fs_descriptors instead of ss_descriptors for determining the
endpoint count for a particular configuration.
- Re-ordered patch series to fix patch dependencies.
Changes in V5:
- Added check_config() logic, which is used to communicate the number of EPs
used in a particular configuration. Based on this, the DWC3 gadget driver
has the ability to know the maximum number of eps utilized in all configs.
This helps reduce unnecessary allocation to unused eps, and will catch fifo
allocation issues at bind() time.
- Fixed variable declaration to single line per variable, and reverse xmas.
- Created a helper for fifo clearing, which is used by ep0.c
Changes in V4:
- Removed struct dwc3* as an argument for dwc3_gadget_resize_tx_fifos()
- Removed WARN_ON(1) in case we run out of fifo space
Changes in V3:
- Removed "Reviewed-by" tags
- Renamed series back to RFC
- Modified logic to ensure that fifo_size is reset if we pass the minimum
threshold. Tested with binding multiple FDs requesting 6 FIFOs.
Changes in V2:
- Modified TXFIFO resizing logic to ensure that each EP is reserved a
FIFO.
- Removed dev_dbg() prints and fixed typos from patches
- Added some more description on the dt-bindings commit message
Currently, there is no functionality to allow for resizing the TXFIFOs, and
relying on the HW default setting for the TXFIFO depth. In most cases, the
HW default is probably sufficient, but for USB compositions that contain
multiple functions that require EP bursting, the default settings
might not be enough. Also to note, the current SW will assign an EP to a
function driver w/o checking to see if the TXFIFO size for that particular
EP is large enough. (this is a problem if there are multiple HW defined
values for the TXFIFO size)
It is mentioned in the SNPS databook that a minimum of TX FIFO depth = 3
is required for an EP that supports bursting. Otherwise, there may be
frequent occurences of bursts ending. For high bandwidth functions,
such as data tethering (protocols that support data aggregation), mass
storage, and media transfer protocol (over FFS), the bMaxBurst value can be
large, and a bigger TXFIFO depth may prove to be beneficial in terms of USB
throughput. (which can be associated to system access latency, etc...) It
allows for a more consistent burst of traffic, w/o any interruptions, as
data is readily available in the FIFO.
With testing done using the mass storage function driver, the results show
that with a larger TXFIFO depth, the bandwidth increased significantly.
Test Parameters:
- Platform: Qualcomm SM8150
- bMaxBurst = 6
- USB req size = 256kB
- Num of USB reqs = 16
- USB Speed = Super-Speed
- Function Driver: Mass Storage (w/ ramdisk)
- Test Application: CrystalDiskMark
Results:
TXFIFO Depth = 3 max packets
Test Case | Data Size | AVG tput (in MB/s)
-------------------------------------------
Sequential|1 GB x |
Read |9 loops | 193.60
| | 195.86
| | 184.77
| | 193.60
-------------------------------------------
TXFIFO Depth = 6 max packets
Test Case | Data Size | AVG tput (in MB/s)
-------------------------------------------
Sequential|1 GB x |
Read |9 loops | 287.35
| | 304.94
| | 289.64
| | 293.61
-------------------------------------------
Wesley Cheng (5):
usb: gadget: udc: core: Introduce check_config to verify USB
configuration
usb: gadget: configfs: Check USB configuration before adding
usb: dwc3: Resize TX FIFOs to meet EP bursting requirements
usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default
arm64: boot: dts: qcom: sm8150: Enable dynamic TX FIFO resize logic
arch/arm64/boot/dts/qcom/sm8150.dtsi | 1 +
drivers/usb/dwc3/core.c | 9 ++
drivers/usb/dwc3/core.h | 15 +++
drivers/usb/dwc3/dwc3-qcom.c | 9 ++
drivers/usb/dwc3/ep0.c | 2 +
drivers/usb/dwc3/gadget.c | 212 +++++++++++++++++++++++++++++++++++
drivers/usb/gadget/configfs.c | 22 ++++
drivers/usb/gadget/udc/core.c | 25 +++++
include/linux/usb/gadget.h | 5 +
9 files changed, 300 insertions(+)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Ensure that the USB gadget is able to support the configuration being
added based on the number of endpoints required from all interfaces. This
is for accounting for any bandwidth or space limitations.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/gadget/configfs.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 15a607c..76b9983 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -1374,6 +1374,7 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
struct usb_function *f;
struct usb_function *tmp;
struct gadget_config_name *cn;
+ unsigned long ep_map = 0;
if (gadget_is_otg(gadget))
c->descriptors = otg_desc;
@@ -1403,7 +1404,28 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
list_add(&f->list, &cfg->func_list);
goto err_purge_funcs;
}
+ if (f->fs_descriptors) {
+ struct usb_descriptor_header **d;
+
+ d = f->fs_descriptors;
+ for (; *d; ++d) {
+ struct usb_endpoint_descriptor *ep;
+ int addr;
+
+ if ((*d)->bDescriptorType != USB_DT_ENDPOINT)
+ continue;
+
+ ep = (struct usb_endpoint_descriptor *)*d;
+ addr = ((ep->bEndpointAddress & 0x80) >> 3) |
+ (ep->bEndpointAddress & 0x0f);
+ set_bit(addr, &ep_map);
+ }
+ }
}
+ ret = usb_gadget_check_config(cdev->gadget, ep_map);
+ if (ret)
+ goto err_purge_funcs;
+
usb_ep_autoconfig_reset(cdev->gadget);
}
if (cdev->use_os_string) {
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
In order to take advantage of the TX fifo resizing logic, manually add
these properties to the DWC3 child node by default. This will allow
the DWC3 gadget to resize the TX fifos for the IN endpoints, which
help with performance.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/dwc3/dwc3-qcom.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index 49e6ca9..44e0eaa1 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -645,6 +645,7 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
struct dwc3_qcom *qcom = platform_get_drvdata(pdev);
struct device_node *np = pdev->dev.of_node, *dwc3_np;
struct device *dev = &pdev->dev;
+ struct property *prop;
int ret;
dwc3_np = of_get_compatible_child(np, "snps,dwc3");
@@ -653,6 +654,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
return -ENODEV;
}
+ prop = devm_kzalloc(dev, sizeof(*prop), GFP_KERNEL);
+ if (prop) {
+ prop->name = "tx-fifo-resize";
+ ret = of_add_property(dwc3_np, prop);
+ if (ret < 0)
+ dev_info(dev, "unable to add tx-fifo-resize prop\n");
+ }
+
ret = of_platform_populate(np, NULL, NULL, dev);
if (ret) {
dev_err(dev, "failed to register dwc3 core - %d\n", ret);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Some UDCs may have constraints on how many high bandwidth endpoints it can
support in a certain configuration. This API allows for the composite
driver to pass down the total number of endpoints to the UDC so it can verify
it has the required resources to support the configuration.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/gadget/udc/core.c | 25 +++++++++++++++++++++++++
include/linux/usb/gadget.h | 5 +++++
2 files changed, 30 insertions(+)
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 493ff93..e67fd93 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1003,6 +1003,31 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
}
EXPORT_SYMBOL_GPL(usb_gadget_ep_match_desc);
+/**
+ * usb_gadget_check_config - checks if the UDC can support the number of eps
+ * @gadget: controller to check the USB configuration
+ * @ep_map: bitmap of endpoints being requested by a USB configuration
+ *
+ * Ensure that a UDC is able to support the number of endpoints within a USB
+ * configuration, and that there are no resource limitations to support all
+ * requested eps.
+ *
+ * Returns zero on success, else a negative errno.
+ */
+int usb_gadget_check_config(struct usb_gadget *gadget, unsigned long ep_map)
+{
+ int ret = 0;
+
+ if (!gadget->ops->check_config)
+ goto out;
+
+ ret = gadget->ops->check_config(gadget, ep_map);
+
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_check_config);
+
/* ------------------------------------------------------------------------- */
static void usb_gadget_state_work(struct work_struct *work)
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index ee04ef2..9fb69eb 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -328,6 +328,7 @@ struct usb_gadget_ops {
struct usb_ep *(*match_ep)(struct usb_gadget *,
struct usb_endpoint_descriptor *,
struct usb_ss_ep_comp_descriptor *);
+ int (*check_config)(struct usb_gadget *gadget, unsigned long ep_map);
};
/**
@@ -607,6 +608,7 @@ int usb_gadget_connect(struct usb_gadget *gadget);
int usb_gadget_disconnect(struct usb_gadget *gadget);
int usb_gadget_deactivate(struct usb_gadget *gadget);
int usb_gadget_activate(struct usb_gadget *gadget);
+int usb_gadget_check_config(struct usb_gadget *gadget, unsigned long ep_map);
#else
static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
{ return 0; }
@@ -630,6 +632,9 @@ static inline int usb_gadget_deactivate(struct usb_gadget *gadget)
{ return 0; }
static inline int usb_gadget_activate(struct usb_gadget *gadget)
{ return 0; }
+static inline int usb_gadget_check_config(struct usb_gadget *gadget,
+ unsigned long ep_map)
+{ return 0; }
#endif /* CONFIG_USB_GADGET */
/*-------------------------------------------------------------------------*/
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Hi Felipe,
Sorry for the ping, but was just wondering if you had any feedback on
the latest txfifo resize patch series? I think I addressed the concerns
you had about making sure we had enough FIFO size for a composition
before allowing the configuration to bind with the check_config() API.
It would ensure at least enough room for 1 max packet size for each EP
in a configuration before allowing the bind to complete.
That way we'd avoid being enumerated w/ the host, and having
non-functioning endpoints. We've been testing these changes internally,
and they are providing a pretty significant boost to our USB throughput
numbers.
Thanks
Wesley Cheng
On 5/19/2021 12:43 AM, Wesley Cheng wrote:
> Changes in V8:
> - Rebased to usb-testing
> - Using devm_kzalloc for adding txfifo property in dwc3-qcom
> - Removed DWC3 QCOM ACPI property for enabling the txfifo resize
>
> Changes in V7:
> - Added a new property tx-fifo-max-num for limiting how much fifo space the
> resizing logic can allocate for endpoints with large burst values. This
> can differ across platforms, and tie in closely with overall system latency.
> - Added recommended checks for DWC32.
> - Added changes to set the tx-fifo-resize property from dwc3-qcom by default
> instead of modifying the current DTSI files.
> - Added comments on all APIs/variables introduced.
> - Updated the DWC3 YAML to include a better description of the tx-fifo-resize
> property and added an entry for tx-fifo-max-num.
>
> Changes in V6:
> - Rebased patches to usb-testing.
> - Renamed to PATCH series instead of RFC.
> - Checking for fs_descriptors instead of ss_descriptors for determining the
> endpoint count for a particular configuration.
> - Re-ordered patch series to fix patch dependencies.
>
> Changes in V5:
> - Added check_config() logic, which is used to communicate the number of EPs
> used in a particular configuration. Based on this, the DWC3 gadget driver
> has the ability to know the maximum number of eps utilized in all configs.
> This helps reduce unnecessary allocation to unused eps, and will catch fifo
> allocation issues at bind() time.
> - Fixed variable declaration to single line per variable, and reverse xmas.
> - Created a helper for fifo clearing, which is used by ep0.c
>
> Changes in V4:
> - Removed struct dwc3* as an argument for dwc3_gadget_resize_tx_fifos()
> - Removed WARN_ON(1) in case we run out of fifo space
>
> Changes in V3:
> - Removed "Reviewed-by" tags
> - Renamed series back to RFC
> - Modified logic to ensure that fifo_size is reset if we pass the minimum
> threshold. Tested with binding multiple FDs requesting 6 FIFOs.
>
> Changes in V2:
> - Modified TXFIFO resizing logic to ensure that each EP is reserved a
> FIFO.
> - Removed dev_dbg() prints and fixed typos from patches
> - Added some more description on the dt-bindings commit message
>
> Currently, there is no functionality to allow for resizing the TXFIFOs, and
> relying on the HW default setting for the TXFIFO depth. In most cases, the
> HW default is probably sufficient, but for USB compositions that contain
> multiple functions that require EP bursting, the default settings
> might not be enough. Also to note, the current SW will assign an EP to a
> function driver w/o checking to see if the TXFIFO size for that particular
> EP is large enough. (this is a problem if there are multiple HW defined
> values for the TXFIFO size)
>
> It is mentioned in the SNPS databook that a minimum of TX FIFO depth = 3
> is required for an EP that supports bursting. Otherwise, there may be
> frequent occurences of bursts ending. For high bandwidth functions,
> such as data tethering (protocols that support data aggregation), mass
> storage, and media transfer protocol (over FFS), the bMaxBurst value can be
> large, and a bigger TXFIFO depth may prove to be beneficial in terms of USB
> throughput. (which can be associated to system access latency, etc...) It
> allows for a more consistent burst of traffic, w/o any interruptions, as
> data is readily available in the FIFO.
>
> With testing done using the mass storage function driver, the results show
> that with a larger TXFIFO depth, the bandwidth increased significantly.
>
> Test Parameters:
> - Platform: Qualcomm SM8150
> - bMaxBurst = 6
> - USB req size = 256kB
> - Num of USB reqs = 16
> - USB Speed = Super-Speed
> - Function Driver: Mass Storage (w/ ramdisk)
> - Test Application: CrystalDiskMark
>
> Results:
>
> TXFIFO Depth = 3 max packets
>
> Test Case | Data Size | AVG tput (in MB/s)
> -------------------------------------------
> Sequential|1 GB x |
> Read |9 loops | 193.60
> | | 195.86
> | | 184.77
> | | 193.60
> -------------------------------------------
>
> TXFIFO Depth = 6 max packets
>
> Test Case | Data Size | AVG tput (in MB/s)
> -------------------------------------------
> Sequential|1 GB x |
> Read |9 loops | 287.35
> | | 304.94
> | | 289.64
> | | 293.61
> -------------------------------------------
>
> Wesley Cheng (5):
> usb: gadget: udc: core: Introduce check_config to verify USB
> configuration
> usb: gadget: configfs: Check USB configuration before adding
> usb: dwc3: Resize TX FIFOs to meet EP bursting requirements
> usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default
> arm64: boot: dts: qcom: sm8150: Enable dynamic TX FIFO resize logic
>
> arch/arm64/boot/dts/qcom/sm8150.dtsi | 1 +
> drivers/usb/dwc3/core.c | 9 ++
> drivers/usb/dwc3/core.h | 15 +++
> drivers/usb/dwc3/dwc3-qcom.c | 9 ++
> drivers/usb/dwc3/ep0.c | 2 +
> drivers/usb/dwc3/gadget.c | 212 +++++++++++++++++++++++++++++++++++
> drivers/usb/gadget/configfs.c | 22 ++++
> drivers/usb/gadget/udc/core.c | 25 +++++
> include/linux/usb/gadget.h | 5 +
> 9 files changed, 300 insertions(+)
>
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project