[PATCH v2] PCI: rockchip: Support property to specify the link capability
Brian Norris
briannorris at chromium.org
Tue Oct 4 21:36:48 PDT 2016
Hi Shawn,
On Wed, Oct 05, 2016 at 11:06:16AM +0800, Shawn Lin wrote:
> From: Brian Norris <briannorris at chromium.org>
>
> rk3399 supports PCIe 2.x link speeds marginally at best, and on some
> boards, the link won't train at 5 GT/s at all. Rather than sacrifice 500
> ms waiting for training that will never happen, let's add a property
> from devicetree to specify link capability.
>
> Signed-off-by: Brian Norris <briannorris at chromium.org>
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
>
> ---
>
> Changes in v2:
> - rename the property to rockchip,max-link-speed according to
> Bjorn's recommendation and take some bits from imx6q-pcie to
> make this requirement more consisent.
>
> .../devicetree/bindings/pci/rockchip-pcie.txt | 2 +
> drivers/pci/host/pcie-rockchip.c | 61 ++++++++++++++--------
> 2 files changed, 41 insertions(+), 22 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/pci/rockchip-pcie.txt b/Documentation/devicetree/bindings/pci/rockchip-pcie.txt
> index ba67b39..8335f03 100644
> --- a/Documentation/devicetree/bindings/pci/rockchip-pcie.txt
> +++ b/Documentation/devicetree/bindings/pci/rockchip-pcie.txt
> @@ -42,6 +42,8 @@ Required properties:
> Optional Property:
> - ep-gpios: contain the entry for pre-reset gpio
> - num-lanes: number of lanes to use
> +- rockchip,max-link-speed: Specify PCI gen for link capability. Must
> + be '2' for gen2, otherwise will default to gen1.
> - vpcie3v3-supply: The phandle to the 3.3v regulator to use for PCIe.
> - vpcie1v8-supply: The phandle to the 1.8v regulator to use for PCIe.
> - vpcie0v9-supply: The phandle to the 0.9v regulator to use for PCIe.
> diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
> index 35591b1..ca3db51 100644
> --- a/drivers/pci/host/pcie-rockchip.c
> +++ b/drivers/pci/host/pcie-rockchip.c
> @@ -53,6 +53,7 @@
> #define PCIE_CLIENT_ARI_ENABLE HIWORD_UPDATE_BIT(0x0008)
> #define PCIE_CLIENT_CONF_LANE_NUM(x) HIWORD_UPDATE(0x0030, ENCODE_LANES(x))
> #define PCIE_CLIENT_MODE_RC HIWORD_UPDATE_BIT(0x0040)
> +#define PCIE_CLIENT_GEN_SEL_1 HIWORD_UPDATE(0x0080, 0)
> #define PCIE_CLIENT_GEN_SEL_2 HIWORD_UPDATE_BIT(0x0080)
> #define PCIE_CLIENT_BASIC_STATUS1 (PCIE_CLIENT_BASE + 0x48)
> #define PCIE_CLIENT_LINK_STATUS_UP 0x00300000
> @@ -205,6 +206,7 @@ struct rockchip_pcie {
> struct gpio_desc *ep_gpio;
> u32 lanes;
> u8 root_bus_nr;
> + int link_gen;
> struct device *dev;
> struct irq_domain *irq_domain;
> };
> @@ -443,13 +445,21 @@ static int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
> return err;
> }
>
> + if (rockchip->link_gen == 2) {
> + rockchip_pcie_write(rockchip, PCIE_CLIENT_GEN_SEL_2,
> + PCIE_CLIENT_CONFIG);
> + } else {
> + rockchip_pcie_write(rockchip, PCIE_CLIENT_GEN_SEL_1,
> + PCIE_CLIENT_CONFIG);
> + dev_info(dev, "max link speed is gen 1\n");
> + }
> +
> rockchip_pcie_write(rockchip,
> PCIE_CLIENT_CONF_ENABLE |
> PCIE_CLIENT_LINK_TRAIN_ENABLE |
> PCIE_CLIENT_ARI_ENABLE |
> PCIE_CLIENT_CONF_LANE_NUM(rockchip->lanes) |
> - PCIE_CLIENT_MODE_RC |
> - PCIE_CLIENT_GEN_SEL_2,
> + PCIE_CLIENT_MODE_RC,
> PCIE_CLIENT_CONFIG);
>
> err = phy_power_on(rockchip->phy);
> @@ -550,29 +560,31 @@ static int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
> msleep(20);
> }
>
> - /*
> - * Enable retrain for gen2. This should be configured only after
> - * gen1 finished.
> - */
> - status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_LCS);
> - status |= PCIE_RC_CONFIG_LCS_RETRAIN_LINK;
> - rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_LCS);
> + if (rockchip->link_gen == 2) {
> + /*
> + * Enable retrain for gen2. This should be configured only after
> + * gen1 finished.
> + */
> + status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_LCS);
> + status |= PCIE_RC_CONFIG_LCS_RETRAIN_LINK;
> + rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_LCS);
> +
> + timeout = jiffies + msecs_to_jiffies(500);
> + for (;;) {
> + status = rockchip_pcie_read(rockchip, PCIE_CORE_CTRL);
> + if ((status & PCIE_CORE_PL_CONF_SPEED_MASK) ==
> + PCIE_CORE_PL_CONF_SPEED_5G) {
> + dev_dbg(dev, "PCIe link training gen2 pass!\n");
> + break;
> + }
>
> - timeout = jiffies + msecs_to_jiffies(500);
> - for (;;) {
> - status = rockchip_pcie_read(rockchip, PCIE_CORE_CTRL);
> - if ((status & PCIE_CORE_PL_CONF_SPEED_MASK) ==
> - PCIE_CORE_PL_CONF_SPEED_5G) {
> - dev_dbg(dev, "PCIe link training gen2 pass!\n");
> - break;
> - }
> + if (time_after(jiffies, timeout)) {
> + dev_dbg(dev, "PCIe link training gen2 timeout, fall back to gen1!\n");
> + break;
> + }
>
> - if (time_after(jiffies, timeout)) {
> - dev_dbg(dev, "PCIe link training gen2 timeout, fall back to gen1!\n");
> - break;
> + msleep(20);
> }
> -
> - msleep(20);
> }
>
> /* Check the final link width from negotiated lane counter from MGMT */
> @@ -781,6 +793,11 @@ static int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
> rockchip->lanes = 1;
> }
>
> + err = of_property_read_u32(node, "rockchip,max-link-speed",
> + &rockchip->link_gen);
> + if (err)
> + rockchip->link_gen = 1;
I realize you copied this from the IMX6 driver, but this allows people
to put anything but '2' in the property, and we'll treat it like '1'.
How about in the !err case, we check that the value is either 1 or 2,
and return an error for anything else?
Brian
> +
> rockchip->core_rst = devm_reset_control_get(dev, "core");
> if (IS_ERR(rockchip->core_rst)) {
> if (PTR_ERR(rockchip->core_rst) != -EPROBE_DEFER)
> --
> 2.3.7
>
>
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