usb: cdnsp: Fix issue with resuming from L1

In very rare cases after resuming controller from L1 to L0 it reads
registers before the clock UTMI have been enabled and as the result
driver reads incorrect value.
Most of registers are in APB domain clock but some of them (e.g. PORTSC)
are in UTMI domain clock.
After entering to L1 state the UTMI clock can be disabled.
When controller transition from L1 to L0 the port status change event is
reported and in interrupt runtime function driver reads PORTSC.
During this read operation controller synchronize UTMI and APB domain
but UTMI clock is still disabled and in result it reads 0xFFFFFFFF value.
To fix this issue driver increases APB timeout value.

The issue is platform specific and if the default value of APB timeout
is not sufficient then this time should be set Individually for each
platform.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/PH7PR07MB953846C57973E4DB134CAA71DDBF2@PH7PR07MB9538.namprd07.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/cdnsp-gadget.c b/drivers/usb/cdns3/cdnsp-gadget.c
index 87f310841735..7f5534db2086 100644
--- a/drivers/usb/cdns3/cdnsp-gadget.c
+++ b/drivers/usb/cdns3/cdnsp-gadget.c
@@ -139,6 +139,26 @@ static void cdnsp_clear_port_change_bit(struct cdnsp_device *pdev,
 	       (portsc & PORT_CHANGE_BITS), port_regs);
 }
 
+static void cdnsp_set_apb_timeout_value(struct cdnsp_device *pdev)
+{
+	struct cdns *cdns = dev_get_drvdata(pdev->dev);
+	__le32 __iomem *reg;
+	void __iomem *base;
+	u32 offset = 0;
+	u32 val;
+
+	if (!cdns->override_apb_timeout)
+		return;
+
+	base = &pdev->cap_regs->hc_capbase;
+	offset = cdnsp_find_next_ext_cap(base, offset, D_XEC_PRE_REGS_CAP);
+	reg = base + offset + REG_CHICKEN_BITS_3_OFFSET;
+
+	val  = le32_to_cpu(readl(reg));
+	val = CHICKEN_APB_TIMEOUT_SET(val, cdns->override_apb_timeout);
+	writel(cpu_to_le32(val), reg);
+}
+
 static void cdnsp_set_chicken_bits_2(struct cdnsp_device *pdev, u32 bit)
 {
 	__le32 __iomem *reg;
@@ -1798,6 +1818,15 @@ static int cdnsp_gen_setup(struct cdnsp_device *pdev)
 	pdev->hci_version = HC_VERSION(pdev->hcc_params);
 	pdev->hcc_params = readl(&pdev->cap_regs->hcc_params);
 
+	/*
+	 * Override the APB timeout value to give the controller more time for
+	 * enabling UTMI clock and synchronizing APB and UTMI clock domains.
+	 * This fix is platform specific and is required to fixes issue with
+	 * reading incorrect value from PORTSC register after resuming
+	 * from L1 state.
+	 */
+	cdnsp_set_apb_timeout_value(pdev);
+
 	cdnsp_get_rev_cap(pdev);
 
 	/* Make sure the Device Controller is halted. */