b90e8d5d28
commit fca3f138105727c3a22edda32d02f91ce1bf11c9 upstream
Originally the procedure of the ULPI transaction finish detection has been
developed as a simple busy-loop with just decrementing counter and no
delays. It's wrong since on different systems the loop will take a
different time to complete. So if the system bus and CPU are fast enough
to overtake the ULPI bus and the companion PHY reaction, then we'll get to
take a false timeout error. Fix this by converting the busy-loop procedure
to take the standard bus speed, address value and the registers access
mode into account for the busy-loop delay calculation.
Here is the way the fix works. It's known that the ULPI bus is clocked
with 60MHz signal. In accordance with [1] the ULPI bus protocol is created
so to spend 5 and 6 clock periods for immediate register write and read
operations respectively, and 6 and 7 clock periods - for the extended
register writes and reads. Based on that we can easily pre-calculate the
time which will be needed for the controller to perform a requested IO
operation. Note we'll still preserve the attempts counter in case if the
DWC USB3 controller has got some internals delays.
[1] UTMI+ Low Pin Interface (ULPI) Specification, Revision 1.1,
October 20, 2004, pp. 30 - 36.
Fixes: 88bc9d194f ("usb: dwc3: add ULPI interface support")
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201210085008.13264-3-Sergey.Semin@baikalelectronics.ru
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
113 lines
2.5 KiB
C
113 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/**
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* ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
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*
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* Copyright (C) 2015 Intel Corporation
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*
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* Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
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*/
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#include <linux/delay.h>
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#include <linux/time64.h>
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#include <linux/ulpi/regs.h>
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#include "core.h"
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#include "io.h"
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#define DWC3_ULPI_ADDR(a) \
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((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
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DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
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DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
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#define DWC3_ULPI_BASE_DELAY DIV_ROUND_UP(NSEC_PER_SEC, 60000000L)
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static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read)
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{
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unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY;
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unsigned int count = 1000;
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u32 reg;
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if (addr >= ULPI_EXT_VENDOR_SPECIFIC)
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ns += DWC3_ULPI_BASE_DELAY;
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if (read)
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ns += DWC3_ULPI_BASE_DELAY;
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while (count--) {
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ndelay(ns);
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reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
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if (reg & DWC3_GUSB2PHYACC_DONE)
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return 0;
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cpu_relax();
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}
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return -ETIMEDOUT;
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}
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static int dwc3_ulpi_read(struct device *dev, u8 addr)
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{
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struct dwc3 *dwc = dev_get_drvdata(dev);
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u32 reg;
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int ret;
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reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
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if (reg & DWC3_GUSB2PHYCFG_SUSPHY) {
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reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
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dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
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}
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reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
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dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
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ret = dwc3_ulpi_busyloop(dwc, addr, true);
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if (ret)
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return ret;
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reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
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return DWC3_GUSB2PHYACC_DATA(reg);
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}
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static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val)
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{
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struct dwc3 *dwc = dev_get_drvdata(dev);
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u32 reg;
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reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
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if (reg & DWC3_GUSB2PHYCFG_SUSPHY) {
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reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
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dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
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}
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reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
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reg |= DWC3_GUSB2PHYACC_WRITE | val;
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dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
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return dwc3_ulpi_busyloop(dwc, addr, false);
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}
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static const struct ulpi_ops dwc3_ulpi_ops = {
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.read = dwc3_ulpi_read,
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.write = dwc3_ulpi_write,
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};
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int dwc3_ulpi_init(struct dwc3 *dwc)
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{
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/* Register the interface */
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dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
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if (IS_ERR(dwc->ulpi)) {
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dev_err(dwc->dev, "failed to register ULPI interface");
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return PTR_ERR(dwc->ulpi);
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}
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return 0;
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}
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void dwc3_ulpi_exit(struct dwc3 *dwc)
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{
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if (dwc->ulpi) {
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ulpi_unregister_interface(dwc->ulpi);
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dwc->ulpi = NULL;
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}
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}
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