[PATCH v2 11/16] PCI: dwc: qcom: Use cached PCIe capability offset

[Hans Zhang]

dw_pcie_host_init() caches the offset after .init, so .post_init callbacks
and later functions (.link_up, icc_opp_update) can use pci->pcie_cap
directly. For .init itself, we must call dw_pcie_get_pcie_cap() inside
qcom_pcie_host_init() to obtain the offset (hardware is already enabled).

Signed-off-by: Hans Zhang <18255117159@xxxxxxx>
---
In pcie-qcom, dw_pcie_find_capability() appears in multiple call chains:

  static const struct dw_pcie_host_ops qcom_pcie_dw_ops = {
    .init = qcom_pcie_host_init,
  };
  qcom_pcie_host_init()
    -> qcom_pcie_clear_aspm_l0s()
      -> dw_pcie_find_capability()

  static const struct qcom_pcie_ops ops_* = {
    .post_init = qcom_pcie_post_init_*,
  };
  qcom_pcie_post_init_*()
    -> qcom_pcie_set_slot_nccs()  (for many versions)
      -> dw_pcie_find_capability()
    -> For 2_3_3 and 2_9_0: also calls dw_pcie_find_capability() directly

  static const struct dw_pcie_ops dw_pcie_ops = {
    .link_up = qcom_pcie_link_up,
  };
  qcom_pcie_link_up()
    -> dw_pcie_find_capability()

  qcom_pcie_probe()
    -> dw_pcie_host_init()
    -> qcom_pcie_icc_opp_update()
      -> dw_pcie_find_capability()
---
 drivers/pci/controller/dwc/pcie-qcom.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 11fc60489892..80783353d539 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -341,13 +341,13 @@ static int qcom_pcie_start_link(struct dw_pcie *pci)
 static void qcom_pcie_clear_aspm_l0s(struct dw_pcie *pci)
 {
 	struct qcom_pcie *pcie = to_qcom_pcie(pci);
-	u16 offset;
+	u8 offset;
 	u32 val;
 
 	if (!pcie->cfg->no_l0s)
 		return;
 
-	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	offset = dw_pcie_get_pcie_cap(pci);
 
 	dw_pcie_dbi_ro_wr_en(pci);
 
@@ -360,7 +360,6 @@ static void qcom_pcie_clear_aspm_l0s(struct dw_pcie *pci)
 
 static void qcom_pcie_set_slot_nccs(struct dw_pcie *pci)
 {
-	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
 	u32 val;
 
 	dw_pcie_dbi_ro_wr_en(pci);
@@ -370,9 +369,9 @@ static void qcom_pcie_set_slot_nccs(struct dw_pcie *pci)
 	 * notifications for the Hot-Plug commands. So set the NCCS field to
 	 * avoid waiting for the completions.
 	 */
-	val = readl(pci->dbi_base + offset + PCI_EXP_SLTCAP);
+	val = readl(pci->dbi_base + pci->pcie_cap + PCI_EXP_SLTCAP);
 	val |= PCI_EXP_SLTCAP_NCCS;
-	writel(val, pci->dbi_base + offset + PCI_EXP_SLTCAP);
+	writel(val, pci->dbi_base + pci->pcie_cap + PCI_EXP_SLTCAP);
 
 	dw_pcie_dbi_ro_wr_dis(pci);
 }
@@ -935,7 +934,7 @@ static int qcom_pcie_init_2_3_3(struct qcom_pcie *pcie)
 static int qcom_pcie_post_init_2_3_3(struct qcom_pcie *pcie)
 {
 	struct dw_pcie *pci = pcie->pci;
-	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	u8 offset = pci->pcie_cap;
 	u32 val;
 
 	/* Force PHY out of lowest power state */
@@ -1257,7 +1256,7 @@ static int qcom_pcie_init_2_9_0(struct qcom_pcie *pcie)
 static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
 {
 	struct dw_pcie *pci = pcie->pci;
-	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	u8 offset = pci->pcie_cap;
 	u32 val;
 	int i;
 
@@ -1303,8 +1302,7 @@ static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
 
 static bool qcom_pcie_link_up(struct dw_pcie *pci)
 {
-	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
-	u16 val = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
+	u16 val = readw(pci->dbi_base + pci->pcie_cap + PCI_EXP_LNKSTA);
 
 	return val & PCI_EXP_LNKSTA_DLLLA;
 }
@@ -1663,15 +1661,14 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
 
 static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
 {
-	u32 offset, status, width, speed;
+	u32 status, width, speed;
 	struct dw_pcie *pci = pcie->pci;
 	struct dev_pm_opp_key key = {};
 	unsigned long freq_kbps;
 	struct dev_pm_opp *opp;
 	int ret, freq_mbps;
 
-	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
-	status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
+	status = readw(pci->dbi_base + pci->pcie_cap + PCI_EXP_LNKSTA);
 
 	/* Only update constraints if link is up. */
 	if (!(status & PCI_EXP_LNKSTA_DLLLA))
-- 
2.34.1