QCOM PCIe controllers need to disable ASPM before initiating link
re-train. So as part of pre_link_speed_change() disable ASPM and as
part of post_link_speed_change() enable ASPM back.
As the driver needs to enable the ASPM states that are enabled
by the system, save PCI ASPM states before disabling them and
in post_link_speed_change() use the saved ASPM states to enable
back the ASPM.
Update ICC & OPP votes based on the requested speed so that RPMh votes
get updated based on the speed.
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-qcom.c | 63 ++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 02643579707f45fc7279023feb7dbc903e69822d..c4aa193bbdcc928603ae50e8d7029b152d62f977 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -276,10 +276,16 @@ struct qcom_pcie {
struct dentry *debugfs;
bool suspended;
bool use_pm_opp;
+ int aspm_state; /* Store ASPM state used in pre & post link speed change */
};
#define to_qcom_pcie(x) dev_get_drvdata((x)->dev)
+static void qcom_pcie_post_link_speed_change(struct pci_host_bridge *bridge,
+ struct pci_dev *pdev, int current_speed);
+static int qcom_pcie_pre_link_speed_change(struct pci_host_bridge *bridge,
+ struct pci_dev *pdev, int current_speed);
+
static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
{
gpiod_set_value_cansleep(pcie->reset, 1);
@@ -1263,6 +1269,8 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
goto err_assert_reset;
}
+ pp->bridge->pre_link_speed_change = qcom_pcie_pre_link_speed_change;
+ pp->bridge->post_link_speed_change = qcom_pcie_post_link_speed_change;
return 0;
err_assert_reset:
@@ -1328,6 +1336,61 @@ static int qcom_pcie_set_icc_opp(struct qcom_pcie *pcie, int speed, int width)
return ret;
}
+static int qcom_pcie_scale_bw(struct dw_pcie_rp *pp, int speed)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct qcom_pcie *pcie = to_qcom_pcie(pci);
+ u32 offset, status, width;
+
+ offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+ status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
+
+ width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
+
+ return qcom_pcie_set_icc_opp(pcie, speed, width);
+}
+
+static void qcom_pcie_post_link_speed_change(struct pci_host_bridge *bridge,
+ struct pci_dev *pdev, int current_speed)
+{
+ struct dw_pcie_rp *pp = bridge->bus->sysdata;
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct qcom_pcie *pcie = to_qcom_pcie(pci);
+ struct pci_dev *child;
+
+ /* Get function 0 of downstream device */
+ list_for_each_entry(child, &pdev->subordinate->devices, bus_list)
+ if (PCI_FUNC(child->devfn) == 0)
+ break;
+
+ pci_enable_link_state_locked(child, pcie->aspm_state);
+
+ qcom_pcie_scale_bw(pp, current_speed);
+}
+
+static int qcom_pcie_pre_link_speed_change(struct pci_host_bridge *bridge,
+ struct pci_dev *pdev, int target_speed)
+{
+ struct dw_pcie_rp *pp = bridge->bus->sysdata;
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct qcom_pcie *pcie = to_qcom_pcie(pci);
+ struct pci_dev *child;
+
+ /* Get function 0 of downstream device */
+ list_for_each_entry(child, &pdev->subordinate->devices, bus_list)
+ if (PCI_FUNC(child->devfn) == 0)
+ break;
+ /*
+ * QCOM controllers doesn't support link re-train with ASPM enabled.
+ * Disable ASPM as part of pre_link_speed_change() and enable them
+ * back as part of post_link_speed_change().
+ */
+ pcie->aspm_state = pcie_aspm_enabled(child);
+ pci_disable_link_state_locked(child, PCIE_LINK_STATE_ALL);
+
+ return qcom_pcie_scale_bw(pp, target_speed);
+}
+
static const struct dw_pcie_host_ops qcom_pcie_dw_ops = {
.init = qcom_pcie_host_init,
.deinit = qcom_pcie_host_deinit,
--
2.34.1
