[PATCH v7 0/5] Re-introduce TX FIFO resize for larger EP bursting

[PATCH v7 0/5] Re-introduce TX FIFO resize for larger EP bursting

[Wesley Cheng]

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
  dt-bindings: usb: dwc3: Update dwc3 TX fifo properties

 .../devicetree/bindings/usb/snps,dwc3.yaml         |  15 +-
 drivers/usb/dwc3/core.c                            |   9 +
 drivers/usb/dwc3/core.h                            |  15 ++
 drivers/usb/dwc3/dwc3-qcom.c                       |  10 +
 drivers/usb/dwc3/ep0.c                             |   2 +
 drivers/usb/dwc3/gadget.c                          | 214 +++++++++++++++++++++
 drivers/usb/gadget/configfs.c                      |  22 +++
 drivers/usb/gadget/udc/core.c                      |  25 +++
 include/linux/usb/gadget.h                         |   5 +
 9 files changed, 315 insertions(+), 2 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v7 1/5] usb: gadget: udc: core: Introduce check_config to verify USB configuration

[Wesley Cheng]

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 <wcheng@codeaurora.org>
---
 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 4173acd..81252e5 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

[PATCH v7 2/5] usb: gadget: configfs: Check USB configuration before adding

[Wesley Cheng]

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 <wcheng@codeaurora.org>
---
 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 0d56f33..e6de3ca5 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -1368,6 +1368,7 @@ 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;
@@ -1397,7 +1398,28 @@ 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

[PATCH v7 3/5] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements

[Wesley Cheng]

Some devices have USB compositions which may require multiple endpoints
that support EP bursting.  HW defined TX FIFO sizes may not always be
sufficient for these compositions.  By utilizing flexible TX FIFO
allocation, this allows for endpoints to request the required FIFO depth to
achieve higher bandwidth.  With some higher bMaxBurst configurations, using
a larger TX FIFO size results in better TX throughput.

By introducing the check_config() callback, the resizing logic can fetch
the maximum number of endpoints used in the USB composition (can contain
multiple configurations), which helps ensure that the resizing logic can
fulfill the configuration(s), or return an error to the gadget layer
otherwise during bind time.

Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
---
 drivers/usb/dwc3/core.c   |   9 ++
 drivers/usb/dwc3/core.h   |  15 ++++
 drivers/usb/dwc3/ep0.c    |   2 +
 drivers/usb/dwc3/gadget.c | 214 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 240 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 6969196..4f78370 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1238,6 +1238,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	u8			rx_max_burst_prd;
 	u8			tx_thr_num_pkt_prd;
 	u8			tx_max_burst_prd;
+	u8			tx_fifo_resize_max_num;
 
 	/* default to highest possible threshold */
 	lpm_nyet_threshold = 0xf;
@@ -1251,6 +1252,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	 */
 	hird_threshold = 12;
 
+	tx_fifo_resize_max_num = 6;
+
 	dwc->maximum_speed = usb_get_maximum_speed(dev);
 	dwc->dr_mode = usb_get_dr_mode(dev);
 	dwc->hsphy_mode = of_usb_get_phy_mode(dev->of_node);
@@ -1284,6 +1287,10 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				&tx_thr_num_pkt_prd);
 	device_property_read_u8(dev, "snps,tx-max-burst-prd",
 				&tx_max_burst_prd);
+	dwc->do_fifo_resize = device_property_read_bool(dev,
+							"tx-fifo-resize");
+	device_property_read_u8(dev, "tx-fifo-max-num",
+				&tx_fifo_resize_max_num);
 
 	dwc->disable_scramble_quirk = device_property_read_bool(dev,
 				"snps,disable_scramble_quirk");
@@ -1349,6 +1356,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	dwc->tx_max_burst_prd = tx_max_burst_prd;
 
 	dwc->imod_interval = 0;
+
+	dwc->tx_fifo_resize_max_num = tx_fifo_resize_max_num;
 }
 
 /* check whether the core supports IMOD */
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index eec1cf4..411b904 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1007,6 +1007,7 @@ struct dwc3_scratchpad_array {
  * @rx_max_burst_prd: max periodic ESS receive burst size
  * @tx_thr_num_pkt_prd: periodic ESS transmit packet count
  * @tx_max_burst_prd: max periodic ESS transmit burst size
+ * @tx_fifo_resize_max_num: max number of fifos allocated during txfifo resize
  * @hsphy_interface: "utmi" or "ulpi"
  * @connected: true when we're connected to a host, false otherwise
  * @delayed_status: true when gadget driver asks for delayed status
@@ -1062,6 +1063,11 @@ struct dwc3_scratchpad_array {
  * @dis_split_quirk: set to disable split boundary.
  * @imod_interval: set the interrupt moderation interval in 250ns
  *			increments or 0 to disable.
+ * @max_cfg_eps: current max number of IN eps used across all USB configs.
+ * @last_fifo_depth: last fifo depth used to determine next fifo ram start
+ *		     address.
+ * @num_ep_resized: carries the current number endpoints which have had its tx
+ *		    fifo resized.
  */
 struct dwc3 {
 	struct work_struct	drd_work;
@@ -1210,6 +1216,7 @@ struct dwc3 {
 	u8			rx_max_burst_prd;
 	u8			tx_thr_num_pkt_prd;
 	u8			tx_max_burst_prd;
+	u8			tx_fifo_resize_max_num;
 
 	const char		*hsphy_interface;
 
@@ -1223,6 +1230,7 @@ struct dwc3 {
 	unsigned		is_utmi_l1_suspend:1;
 	unsigned		is_fpga:1;
 	unsigned		pending_events:1;
+	unsigned		do_fifo_resize:1;
 	unsigned		pullups_connected:1;
 	unsigned		setup_packet_pending:1;
 	unsigned		three_stage_setup:1;
@@ -1257,6 +1265,10 @@ struct dwc3 {
 	unsigned		dis_split_quirk:1;
 
 	u16			imod_interval;
+
+	int			max_cfg_eps;
+	int			last_fifo_depth;
+	int			num_ep_resized;
 };
 
 #define INCRX_BURST_MODE 0
@@ -1471,6 +1483,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
 		struct dwc3_gadget_ep_cmd_params *params);
 int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned int cmd,
 		u32 param);
+void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc);
 #else
 static inline int dwc3_gadget_init(struct dwc3 *dwc)
 { return 0; }
@@ -1490,6 +1503,8 @@ static inline int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
 static inline int dwc3_send_gadget_generic_command(struct dwc3 *dwc,
 		int cmd, u32 param)
 { return 0; }
+static inline void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc)
+{ }
 #endif
 
 #if IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 8b668ef..4f216bd 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -616,6 +616,8 @@ static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 		return -EINVAL;
 
 	case USB_STATE_ADDRESS:
+		dwc3_gadget_clear_tx_fifos(dwc);
+
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
 		/* if the cfg matches and the cfg is non zero */
 		if (cfg && (!ret || (ret == USB_GADGET_DELAYED_STATUS))) {
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 86f257f..18fe5b5 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -616,6 +616,181 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 		bool interrupt);
 
 /**
+ * dwc3_gadget_calc_tx_fifo_size - calculates the txfifo size value
+ * @dwc: pointer to the DWC3 context
+ * @nfifos: number of fifos to calculate for
+ *
+ * Calculates the size value based on the equation below:
+ *
+ * fifo_size = mult * ((max_packet + mdwidth)/mdwidth + 1) + 1
+ *
+ * The max packet size is set to 1024, as the txfifo requirements mainly apply
+ * to super speed USB use cases.  However, it is safe to overestimate the fifo
+ * allocations for other scenarios, i.e. high speed USB.
+ */
+static int dwc3_gadget_calc_tx_fifo_size(struct dwc3 *dwc, int mult)
+{
+	int max_packet = 1024;
+	int fifo_size;
+	int mdwidth;
+
+	mdwidth = DWC3_MDWIDTH(dwc->hwparams.hwparams0);
+	if (DWC3_IP_IS(DWC32))
+		mdwidth += DWC3_GHWPARAMS6_MDWIDTH(dwc->hwparams.hwparams6);
+
+	/* MDWIDTH is represented in bits, we need it in bytes */
+	mdwidth >>= 3;
+
+	fifo_size = mult * ((max_packet + mdwidth) / mdwidth) + 1;
+	return fifo_size;
+}
+
+/**
+ * dwc3_gadget_clear_tx_fifo_size - Clears txfifo allocation
+ * @dwc: pointer to the DWC3 context
+ *
+ * Iterates through all the endpoint registers and clears the previous txfifo
+ * allocations.
+ */
+void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc)
+{
+	struct dwc3_ep *dep;
+	int fifo_depth;
+	int size;
+	int num;
+
+	if (!dwc->do_fifo_resize)
+		return;
+
+	/* Read ep0IN related TXFIFO size */
+	dep = dwc->eps[1];
+	size = dwc3_readl(dwc->regs, DWC3_GTXFIFOSIZ(0));
+	if (DWC3_IP_IS(DWC3))
+		fifo_depth = DWC3_GTXFIFOSIZ_TXFDEP(size);
+	else
+		fifo_depth = DWC31_GTXFIFOSIZ_TXFDEP(size);
+
+	dwc->last_fifo_depth = fifo_depth;
+	/* Clear existing TXFIFO for all IN eps except ep0 */
+	for (num = 3; num < min_t(int, dwc->num_eps, DWC3_ENDPOINTS_NUM);
+	     num += 2) {
+		dep = dwc->eps[num];
+		/* Don't change TXFRAMNUM on usb31 version */
+		size = DWC3_IP_IS(DWC3) ? 0 :
+			dwc3_readl(dwc->regs, DWC3_GTXFIFOSIZ(num >> 1)) &
+				   DWC31_GTXFIFOSIZ_TXFRAMNUM;
+
+		dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(num >> 1), size);
+	}
+	dwc->num_ep_resized = 0;
+}
+
+/*
+ * dwc3_gadget_resize_tx_fifos - reallocate fifo spaces for current use-case
+ * @dwc: pointer to our context structure
+ *
+ * This function will a best effort FIFO allocation in order
+ * to improve FIFO usage and throughput, while still allowing
+ * us to enable as many endpoints as possible.
+ *
+ * Keep in mind that this operation will be highly dependent
+ * on the configured size for RAM1 - which contains TxFifo -,
+ * the amount of endpoints enabled on coreConsultant tool, and
+ * the width of the Master Bus.
+ *
+ * In general, FIFO depths are represented with the following equation:
+ *
+ * fifo_size = mult * ((max_packet + mdwidth)/mdwidth + 1) + 1
+ *
+ * Conversions can be done to the equation to derive the number of packets that
+ * will fit to a particular FIFO size value.
+ */
+static int dwc3_gadget_resize_tx_fifos(struct dwc3_ep *dep)
+{
+	struct dwc3 *dwc = dep->dwc;
+	int fifo_0_start;
+	int ram1_depth;
+	int fifo_size;
+	int min_depth;
+	int num_in_ep;
+	int remaining;
+	int num_fifos = 1;
+	int fifo;
+	int tmp;
+
+	if (!dwc->do_fifo_resize)
+		return 0;
+
+	/* resize IN endpoints except ep0 */
+	if (!usb_endpoint_dir_in(dep->endpoint.desc) || dep->number <= 1)
+		return 0;
+
+	ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
+
+	if ((dep->endpoint.maxburst > 1 &&
+	     usb_endpoint_xfer_bulk(dep->endpoint.desc)) ||
+	    usb_endpoint_xfer_isoc(dep->endpoint.desc))
+		num_fifos = 3;
+
+	if (dep->endpoint.maxburst > 6 &&
+	    usb_endpoint_xfer_bulk(dep->endpoint.desc) && DWC3_IP_IS(DWC31))
+		num_fifos = dwc->tx_fifo_resize_max_num;
+
+	/* FIFO size for a single buffer */
+	fifo = dwc3_gadget_calc_tx_fifo_size(dwc, 1);
+
+	/* Calculate the number of remaining EPs w/o any FIFO */
+	num_in_ep = dwc->max_cfg_eps;
+	num_in_ep -= dwc->num_ep_resized;
+
+	/* Reserve at least one FIFO for the number of IN EPs */
+	min_depth = num_in_ep * (fifo + 1);
+	remaining = ram1_depth - min_depth - dwc->last_fifo_depth;
+	remaining = max_t(int, 0, remaining);
+	/*
+	 * We've already reserved 1 FIFO per EP, so check what we can fit in
+	 * addition to it.  If there is not enough remaining space, allocate
+	 * all the remaining space to the EP.
+	 */
+	fifo_size = (num_fifos - 1) * fifo;
+	if (remaining < fifo_size)
+		fifo_size = remaining;
+
+	fifo_size += fifo;
+	/* Last increment according to the TX FIFO size equation */
+	fifo_size++;
+
+	/* Check if TXFIFOs start at non-zero addr */
+	tmp = dwc3_readl(dwc->regs, DWC3_GTXFIFOSIZ(0));
+	fifo_0_start = DWC3_GTXFIFOSIZ_TXFSTADDR(tmp);
+
+	fifo_size |= (fifo_0_start + (dwc->last_fifo_depth << 16));
+	if (DWC3_IP_IS(DWC3))
+		dwc->last_fifo_depth += DWC3_GTXFIFOSIZ_TXFDEP(fifo_size);
+	else
+		dwc->last_fifo_depth += DWC31_GTXFIFOSIZ_TXFDEP(fifo_size);
+
+	/* Check fifo size allocation doesn't exceed available RAM size. */
+	if (dwc->last_fifo_depth >= ram1_depth) {
+		dev_err(dwc->dev, "Fifosize(%d) > RAM size(%d) %s depth:%d\n",
+			dwc->last_fifo_depth, ram1_depth,
+			dep->endpoint.name, fifo_size);
+		if (DWC3_IP_IS(DWC3))
+			fifo_size = DWC3_GTXFIFOSIZ_TXFDEP(fifo_size);
+		else
+			fifo_size = DWC31_GTXFIFOSIZ_TXFDEP(fifo_size);
+
+		dwc->last_fifo_depth -= fifo_size;
+		return -ENOMEM;
+	}
+
+	dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(dep->number >> 1), fifo_size);
+	dwc->num_ep_resized++;
+
+	return 0;
+}
+
+/**
  * __dwc3_gadget_ep_enable - initializes a hw endpoint
  * @dep: endpoint to be initialized
  * @action: one of INIT, MODIFY or RESTORE
@@ -632,6 +807,10 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep, unsigned int action)
 	int			ret;
 
 	if (!(dep->flags & DWC3_EP_ENABLED)) {
+		ret = dwc3_gadget_resize_tx_fifos(dep);
+		if (ret)
+			return ret;
+
 		ret = dwc3_gadget_start_config(dep);
 		if (ret)
 			return ret;
@@ -2418,6 +2597,7 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	dwc->gadget_driver	= NULL;
+	dwc->max_cfg_eps = 0;
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	free_irq(dwc->irq_gadget, dwc->ev_buf);
@@ -2485,6 +2665,39 @@ static int dwc3_gadget_vbus_draw(struct usb_gadget *g, unsigned int mA)
 	return 0;
 }
 
+static int dwc3_gadget_check_config(struct usb_gadget *g, unsigned long ep_map)
+{
+	struct dwc3 *dwc = gadget_to_dwc(g);
+	unsigned long in_ep_map;
+	int fifo_size = 0;
+	int ram1_depth;
+	int ep_num;
+
+	if (!dwc->do_fifo_resize)
+		return 0;
+
+	/* Only interested in the IN endpoints */
+	in_ep_map = ep_map >> 16;
+	ep_num = hweight_long(in_ep_map);
+
+	if (ep_num <= dwc->max_cfg_eps)
+		return 0;
+
+	/* Update the max number of eps in the composition */
+	dwc->max_cfg_eps = ep_num;
+
+	fifo_size = dwc3_gadget_calc_tx_fifo_size(dwc, dwc->max_cfg_eps);
+	/* Based on the equation, increment by one for every ep */
+	fifo_size += dwc->max_cfg_eps;
+
+	/* Check if we can fit a single fifo per endpoint */
+	ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
+	if (fifo_size > ram1_depth)
+		return -ENOMEM;
+
+	return 0;
+}
+
 static const struct usb_gadget_ops dwc3_gadget_ops = {
 	.get_frame		= dwc3_gadget_get_frame,
 	.wakeup			= dwc3_gadget_wakeup,
@@ -2495,6 +2708,7 @@ static const struct usb_gadget_ops dwc3_gadget_ops = {
 	.udc_set_speed		= dwc3_gadget_set_speed,
 	.get_config_params	= dwc3_gadget_config_params,
 	.vbus_draw		= dwc3_gadget_vbus_draw,
+	.check_config		= dwc3_gadget_check_config,
 };
 
 /* -------------------------------------------------------------------------- */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Wesley Cheng]

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 <wcheng@codeaurora.org>
---
 drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index d803ee9..4ea6be3 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
 
 static const struct property_entry dwc3_qcom_acpi_properties[] = {
 	PROPERTY_ENTRY_STRING("dr_mode", "host"),
+	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),
 	{}
 };
 
@@ -634,6 +635,7 @@ 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_child_by_name(np, "dwc3");
@@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	prop = kzalloc(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

[PATCH v7 5/5] dt-bindings: usb: dwc3: Update dwc3 TX fifo properties

[Wesley Cheng]

Update the tx-fifo-resize property with a better description, while
adding the tx-fifo-max-num, which is a new parameter allowing
adjustments for the maximum number of packets the txfifo resizing logic
can account for while resizing the endpoints.

Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
---
 Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
index 2247da7..652b246 100644
--- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
@@ -283,10 +283,21 @@ properties:
     maximum: 16
 
   tx-fifo-resize:
-    description: Determines if the FIFO *has* to be reallocated
-    deprecated: true
+    description: Determines if the TX fifos can be dynamically resized depending
+      on the number of IN endpoints used and if bursting is supported.  This
+      may help improve bandwidth on platforms with higher system latencies, as
+      increased fifo space allows for the controller to prefetch data into its
+      internal memory.
     type: boolean
 
+  tx-fifo-max-num:
+    description: Specifies the max number of packets the txfifo resizing logic
+      can account for when higher endpoint bursting is used. (bMaxBurst > 6) The
+      higher the number, the more fifo space the txfifo resizing logic will
+      allocate for that endpoint.
+    $ref: /schemas/types.yaml#/definitions/uint8
+    minimum: 3
+
   snps,incr-burst-type-adjustment:
     description:
       Value for INCR burst type of GSBUSCFG0 register, undefined length INCR
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Jack Pham]

Hi Wesley,

On Thu, Jan 28, 2021 at 08:46:43PM -0800, Wesley Cheng wrote:
> 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 <wcheng@codeaurora.org>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index d803ee9..4ea6be3 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>  
>  static const struct property_entry dwc3_qcom_acpi_properties[] = {
>  	PROPERTY_ENTRY_STRING("dr_mode", "host"),
> +	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),
>  	{}
>  };
>  
> @@ -634,6 +635,7 @@ 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_child_by_name(np, "dwc3");
> @@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> +	prop = kzalloc(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");

You'll need to kfree(prop) both in case of error here as well as in the
driver's .remove() callback. Maybe easier to devm_kzalloc()?

Jack

Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Wesley Cheng]

On 1/29/2021 1:24 AM, Jack Pham wrote:
> Hi Wesley,
> 
> On Thu, Jan 28, 2021 at 08:46:43PM -0800, Wesley Cheng wrote:
>> 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 <wcheng@codeaurora.org>
>> ---
>>  drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
>> index d803ee9..4ea6be3 100644
>> --- a/drivers/usb/dwc3/dwc3-qcom.c
>> +++ b/drivers/usb/dwc3/dwc3-qcom.c
>> @@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>>  
>>  static const struct property_entry dwc3_qcom_acpi_properties[] = {
>>  	PROPERTY_ENTRY_STRING("dr_mode", "host"),
>> +	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),
>>  	{}
>>  };
>>  
>> @@ -634,6 +635,7 @@ 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_child_by_name(np, "dwc3");
>> @@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>>  		return -ENODEV;
>>  	}
>>  
>> +	prop = kzalloc(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");
> 
> You'll need to kfree(prop) both in case of error here as well as in the
> driver's .remove() callback. Maybe easier to devm_kzalloc()?

Hi Jack,

Thanks for the catch, will fix this with the devm variant.

Hi Bjorn,

Just wanted to see what you thought about this approach?  This way we
can just keep the dt binding w/o having to re-add it in the future, as
well as not needing to enable this property on every qcom platform with
dwc3.

Tested on my set up, and removed the change which added the property
from the DTSI node.

Thanks
Wesley Cheng

> 
> Jack
> 

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Bjorn Andersson]

On Thu 28 Jan 22:46 CST 2021, Wesley Cheng wrote:

> 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 <wcheng@codeaurora.org>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index d803ee9..4ea6be3 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>  
>  static const struct property_entry dwc3_qcom_acpi_properties[] = {
>  	PROPERTY_ENTRY_STRING("dr_mode", "host"),
> +	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),

I checked the ACPI tables for Lenovo Miix 630, Yoga C630 and Flex 5G and
neither one has this property specified. So while we could just add this
here, it would have to be done in collaboration with the people who
actually define these. And as said before, I believe we want this to
always be enabled.

>  	{}
>  };
>  
> @@ -634,6 +635,7 @@ 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_child_by_name(np, "dwc3");
> @@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> +	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> +	if (prop) {
> +		prop->name = "tx-fifo-resize";
> +		ret = of_add_property(dwc3_np, prop);

Can't we come up with a way where the platform driver enables this on
the core driver without modifying DT?

Regards,
Bjorn

> +		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
> 

Re: [PATCH v7 5/5] dt-bindings: usb: dwc3: Update dwc3 TX fifo properties

[Rob Herring]

On Thu, 28 Jan 2021 20:46:44 -0800, Wesley Cheng wrote:
> Update the tx-fifo-resize property with a better description, while
> adding the tx-fifo-max-num, which is a new parameter allowing
> adjustments for the maximum number of packets the txfifo resizing logic
> can account for while resizing the endpoints.
> 
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Wesley Cheng]

On 2/2/2021 8:23 AM, Bjorn Andersson wrote:
> On Thu 28 Jan 22:46 CST 2021, Wesley Cheng wrote:
> 
>> 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 <wcheng@codeaurora.org>
>> ---
>>  drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
>> index d803ee9..4ea6be3 100644
>> --- a/drivers/usb/dwc3/dwc3-qcom.c
>> +++ b/drivers/usb/dwc3/dwc3-qcom.c
>> @@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>>  
>>  static const struct property_entry dwc3_qcom_acpi_properties[] = {
>>  	PROPERTY_ENTRY_STRING("dr_mode", "host"),
>> +	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),
> 
> I checked the ACPI tables for Lenovo Miix 630, Yoga C630 and Flex 5G and
> neither one has this property specified. So while we could just add this
> here, it would have to be done in collaboration with the people who
> actually define these. And as said before, I believe we want this to
> always be enabled.
> 
>>  	{}
>>  };
>>  
>> @@ -634,6 +635,7 @@ 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_child_by_name(np, "dwc3");
>> @@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>>  		return -ENODEV;
>>  	}
>>  
>> +	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
>> +	if (prop) {
>> +		prop->name = "tx-fifo-resize";
>> +		ret = of_add_property(dwc3_np, prop);
> 
> Can't we come up with a way where the platform driver enables this on
> the core driver without modifying DT?
> 
> Regards,
> Bjorn

Hi Bjorn,

Sorry for the late response.  As you know, its a little difficult to
access the DWC3 core device during DWC3 qcom probe time, as the DWC3
core will likely return deferred probe due to the PHY devices not being
ready.

This is why I went with the approach to modify the DWC3 node here, so
that when the DWC3 core is eventually probed, it wouldn't miss this
property setting.  If I tried to set this dynamically, say in
dwc3_qcom_vbus_override() (with proper NULL checks), then I'd miss this
setting for the first enumeration, but if cable plug out/in logic is
present, the setting would kick in on subsequent cable events.

Thanks
Wesley Cheng

> 
>> +		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
>>

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project