Bjorn, thanks for the comments!

On 12/16/2015 11:53 PM, Bjorn Helgaas wrote:

On Thu, Dec 03, 2015 at 03:35:22PM +0200, Stanimir Varbanov wrote:

quoted

From: Stanimir Varbanov <redacted>

The PCIe driver reuse the Designware common code for host
and MSI initialization, and also program the Qualcomm
application specific registers.

Signed-off-by: Stanimir Varbanov <redacted>
Signed-off-by: Stanimir Varbanov <redacted>
---
 MAINTAINERS                  |    7 +
 drivers/pci/host/Kconfig     |   10 +
 drivers/pci/host/Makefile    |    1 +
 drivers/pci/host/pcie-qcom.c |  624 ++++++++++++++++++++++++++++++++++++++++++

quoted

+#define PCIE20_CAP				0x70
+#define PCIE20_CAP_LINKCTRLSTATUS		(PCIE20_CAP + 0x10)
+#define PCIE20_CAP_LINKCTRLSTATUS_LINK_UP	BIT(29)

This looks like it could be referring to a standard PCIe Capability;
could you use the existing PCI_EXP_LNKSTA and PCI_EXP_LNKSTA_DLLLA
symbols here?  And readw() instead of readl()?

Yes, that is possible but I still need to keep PCIE20_CAP capabilities
offset.

quoted

+static int qcom_pcie_enable_link_training(struct qcom_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	u32 val;
+	int ret;
+
+	/* enable link training */
+	val = readl(pcie->elbi + PCIE20_ELBI_SYS_CTRL);
+	val |= PCIE20_ELBI_SYS_CTRL_LT_ENABLE;
+	writel(val, pcie->elbi + PCIE20_ELBI_SYS_CTRL);
+
+	/* wait for up to 100ms for the link to come up */
+	ret = readl_poll_timeout(pcie->elbi + PCIE20_ELBI_SYS_STTS, val,
+				 val & XMLH_LINK_UP, LINKUP_DELAY_US,
+				 LINKUP_TIMEOUT_US);
+
+	if (ret < 0 || !dw_pcie_link_up(&pcie->pp)) {
+		dev_err(dev, "link initialization failed\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}

This looks a lot like the *_establish_link() functions in other
DesignWare-based drivers.  Can you make it look even more similar,
e.g., by renaming it to qcom_pcie_establish_link() and maybe moving
some of the PHY functionality here?

readl_poll_timeout() is nice and avoids the hand-coded timeout loop
the other drivers use.  But is there benefit in checking for
XMLH_LINK_UP, or could you simply poll dw_pcie_link_up() like the
others do?  If it's sufficient, I'd prefer using dw_pcie_link_up()
by itself because it's a little more generic.

OK I will modify the code to use dw_pcie_link_up() and ensure that this
check is sufficient.

-- 
regards,
Stan