On Thu, Dec 03, 2015 at 03:35:22PM +0200, Stanimir Varbanov wrote:
> From: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
>
> 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 <svarbanov@xxxxxxxxxx>
> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
> ---
> MAINTAINERS | 7 +
> drivers/pci/host/Kconfig | 10 +
> drivers/pci/host/Makefile | 1 +
> drivers/pci/host/pcie-qcom.c | 624 ++++++++++++++++++++++++++++++++++++++++++
> +#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()?
> +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.
Bjorn
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