usb: dwc3: drop FIFO resizing logic

That FIFO resizing logic was added to support OMAP5
ES1.0 which had a bogus default FIFO size. I can't
remember the exact size of default FIFO, but it was
less than one bulk superspeed packet (<1024) which
would prevent USB3 from ever working on OMAP5 ES1.0.

However, OMAP5 ES1.0 support has been dropped by
commit aa2f4b16f830 ("ARM: OMAP5: id: Remove ES1.0
support") which renders FIFO resizing unnecessary.

Tested-by: Kishon Vijay Abraham I <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

Documentation/devicetree/bindings/usb/dwc3.txt

···
    the second element is expected to be a handle to the USB3/SS PHY
  - phys: from the *Generic PHY* bindings
  - phy-names: from the *Generic PHY* bindings
- - tx-fifo-resize: determines if the FIFO *has* to be reallocated.
  - snps,usb3_lpm_capable: determines if platform is USB3 LPM capable
  - snps,disable_scramble_quirk: true when SW should disable data scrambling.
 	Only really useful for FPGA builds.
···
 	register for post-silicon frame length adjustment when the
 	fladj_30mhz_sdbnd signal is invalid or incorrect.
 
+ - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
+
 This is usually a subnode to DWC3 glue to which it is connected.
 
 dwc3@4a030000 {
···
 	reg = <0x4a030000 0xcfff>;
 	interrupts = <0 92 4>
 	usb-phy = <&usb2_phy>, <&usb3,phy>;
-	tx-fifo-resize;
 };

Documentation/devicetree/bindings/usb/qcom,dwc3.txt

···
 				interrupts = <0 205 0x4>;
 				phys = <&hs_phy>, <&ss_phy>;
 				phy-names = "usb2-phy", "usb3-phy";
-				tx-fifo-resize;
 				dr_mode = "host";
 			};
 		};

drivers/usb/dwc3/core.c

···
 	dwc->usb3_lpm_capable = device_property_read_bool(dev,
 				"snps,usb3_lpm_capable");
 
-	dwc->needs_fifo_resize = device_property_read_bool(dev,
-				"tx-fifo-resize");
-
 	dwc->disable_scramble_quirk = device_property_read_bool(dev,
 				"snps,disable_scramble_quirk");
 	dwc->u2exit_lfps_quirk = device_property_read_bool(dev,
···
 		if (pdata->hird_threshold)
 			hird_threshold = pdata->hird_threshold;
 
-		dwc->needs_fifo_resize = pdata->tx_fifo_resize;
 		dwc->usb3_lpm_capable = pdata->usb3_lpm_capable;
 		dwc->dr_mode = pdata->dr_mode;
 

drivers/usb/dwc3/core.h

···
  * 	0	- utmi_sleep_n
  * 	1	- utmi_l1_suspend_n
  * @is_fpga: true when we are using the FPGA board
- * @needs_fifo_resize: not all users might want fifo resizing, flag it
  * @pullups_connected: true when Run/Stop bit is set
- * @resize_fifos: tells us it's ok to reconfigure our TxFIFO sizes.
  * @setup_packet_pending: true when there's a Setup Packet in FIFO. Workaround
  * @start_config_issued: true when StartConfig command has been issued
  * @three_stage_setup: set if we perform a three phase setup
···
 	unsigned		has_lpm_erratum:1;
 	unsigned		is_utmi_l1_suspend:1;
 	unsigned		is_fpga:1;
-	unsigned		needs_fifo_resize:1;
 	unsigned		pullups_connected:1;
-	unsigned		resize_fifos:1;
 	unsigned		setup_packet_pending:1;
 	unsigned		three_stage_setup:1;
 	unsigned		usb3_lpm_capable:1;
···
 
 /* prototypes */
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode);
-int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc);
 
 /* check whether we are on the DWC_usb31 core */
 static inline bool dwc3_is_usb31(struct dwc3 *dwc)

drivers/usb/dwc3/ep0.c

···
 			reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 			reg |= (DWC3_DCTL_ACCEPTU1ENA | DWC3_DCTL_ACCEPTU2ENA);
 			dwc3_writel(dwc->regs, DWC3_DCTL, reg);
-
-			dwc->resize_fifos = true;
-			dwc3_trace(trace_dwc3_ep0, "resize FIFOs flag SET");
 		}
 		break;
 
···
 
 static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
-	if (dwc->resize_fifos) {
-		dwc3_trace(trace_dwc3_ep0, "Resizing FIFOs");
-		dwc3_gadget_resize_tx_fifos(dwc);
-		dwc->resize_fifos = 0;
-	}
-
 	WARN_ON(dwc3_ep0_start_control_status(dep));
 }
 

drivers/usb/dwc3/gadget.c

···
 	return -ETIMEDOUT;
 }
 
-/**
- * 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 the ideal world, we would always be able to satisfy the
- * following equation:
- *
- * ((512 + 2 * MDWIDTH-Bytes) + (Number of IN Endpoints - 1) * \
- * (3 * (1024 + MDWIDTH-Bytes) + MDWIDTH-Bytes)) / MDWIDTH-Bytes
- *
- * Unfortunately, due to many variables that's not always the case.
- */
-int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
-{
-	int		last_fifo_depth = 0;
-	int		ram1_depth;
-	int		fifo_size;
-	int		mdwidth;
-	int		num;
-
-	if (!dwc->needs_fifo_resize)
-		return 0;
-
-	ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
-	mdwidth = DWC3_MDWIDTH(dwc->hwparams.hwparams0);
-
-	/* MDWIDTH is represented in bits, we need it in bytes */
-	mdwidth >>= 3;
-
-	/*
-	 * FIXME For now we will only allocate 1 wMaxPacketSize space
-	 * for each enabled endpoint, later patches will come to
-	 * improve this algorithm so that we better use the internal
-	 * FIFO space
-	 */
-	for (num = 0; num < dwc->num_in_eps; num++) {
-		/* bit0 indicates direction; 1 means IN ep */
-		struct dwc3_ep	*dep = dwc->eps[(num << 1) | 1];
-		int		mult = 1;
-		int		tmp;
-
-		if (!(dep->flags & DWC3_EP_ENABLED))
-			continue;
-
-		if (usb_endpoint_xfer_bulk(dep->endpoint.desc)
-				|| usb_endpoint_xfer_isoc(dep->endpoint.desc))
-			mult = 3;
-
-		/*
-		 * REVISIT: the following assumes we will always have enough
-		 * space available on the FIFO RAM for all possible use cases.
-		 * Make sure that's true somehow and change FIFO allocation
-		 * accordingly.
-		 *
-		 * If we have Bulk or Isochronous endpoints, we want
-		 * them to be able to be very, very fast. So we're giving
-		 * those endpoints a fifo_size which is enough for 3 full
-		 * packets
-		 */
-		tmp = mult * (dep->endpoint.maxpacket + mdwidth);
-		tmp += mdwidth;
-
-		fifo_size = DIV_ROUND_UP(tmp, mdwidth);
-
-		fifo_size |= (last_fifo_depth << 16);
-
-		dwc3_trace(trace_dwc3_gadget, "%s: Fifo Addr %04x Size %d",
-				dep->name, last_fifo_depth, fifo_size & 0xffff);
-
-		dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(num), fifo_size);
-
-		last_fifo_depth += (fifo_size & 0xffff);
-	}
-
-	return 0;
-}
-
 void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		int status)
 {

drivers/usb/dwc3/platform_data.h

···
 struct dwc3_platform_data {
 	enum usb_device_speed maximum_speed;
 	enum usb_dr_mode dr_mode;
-	bool tx_fifo_resize;
 	bool usb3_lpm_capable;
 
 	unsigned is_utmi_l1_suspend:1;