Add support for assert_perst() for switches like TC9563, which require
configuration before the PCIe link is established. Such devices use
this function op to assert the PERST# before configuring the device
and once the configuration is done they de-assert the PERST#.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 805edbbfe7eba496bc99ca82051dee43d240f359..cdc605b44e19e17319c39933f22d0b7710c5e9ef 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -696,6 +696,18 @@ static int qcom_pcie_post_init_1_0_0(struct qcom_pcie *pcie)
 	return 0;
 }
 
+static int qcom_pcie_assert_perst(struct dw_pcie *pci, bool assert)
+{
+	struct qcom_pcie *pcie = to_qcom_pcie(pci);
+
+	if (assert)
+		qcom_ep_reset_assert(pcie);
+	else
+		qcom_ep_reset_deassert(pcie);
+
+	return 0;
+}
+
 static void qcom_pcie_2_3_2_ltssm_enable(struct qcom_pcie *pcie)
 {
 	u32 val;
@@ -1516,6 +1528,7 @@ static const struct qcom_pcie_cfg cfg_fw_managed = {
 static const struct dw_pcie_ops dw_pcie_ops = {
 	.link_up = qcom_pcie_link_up,
 	.start_link = qcom_pcie_start_link,
+	.assert_perst = qcom_pcie_assert_perst,
 };
 
 static int qcom_pcie_icc_init(struct qcom_pcie *pcie)

-- 
2.34.1