Re: [PATCH V2 14/16] phy: tegra: Add PCIe PIPE2UPHY support

From: Vidya Sagar
Date: Tue Apr 16 2019 - 14:14:33 EST

On 4/15/2019 9:01 PM, Thierry Reding wrote:
On Fri, Apr 05, 2019 at 01:24:41AM +0530, Vidya Sagar wrote:
Synopsys DesignWare core based PCIe controllers in Tegra 194 SoC interface
with Universal PHY (UPHY) module through a PIPE2UPHY (P2U) module.
For each PCIe lane of a controller, there is a P2U unit instantiated at
hardware level. This driver provides support for the programming required
for each P2U that is going to be used for a PCIe controller.

Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
---
Changes since [v1]:
* Added COMPILE_TEST in Kconfig
* Removed empty phy_ops implementations
* Modified code according to DT documentation file modifications

drivers/phy/tegra/Kconfig | 7 ++
drivers/phy/tegra/Makefile | 1 +
drivers/phy/tegra/pcie-p2u-tegra194.c | 120 ++++++++++++++++++++++++++++++++++
3 files changed, 128 insertions(+)
create mode 100644 drivers/phy/tegra/pcie-p2u-tegra194.c

diff --git a/drivers/phy/tegra/Kconfig b/drivers/phy/tegra/Kconfig
index a3b1de953fb7..eb93ee72ecf0 100644
--- a/drivers/phy/tegra/Kconfig
+++ b/drivers/phy/tegra/Kconfig
@@ -6,3 +6,10 @@ config PHY_TEGRA_XUSB
To compile this driver as a module, choose M here: the module will
be called phy-tegra-xusb.
+
+config PHY_TEGRA194_PCIE_P2U
+ tristate "NVIDIA Tegra P2U PHY Driver"
+ depends on ARCH_TEGRA || COMPILE_TEST
+ select GENERIC_PHY
+ help
+ Enable this to support the P2U (PIPE to UPHY) that is part of Tegra 19x SOCs.

This should be using tabs for indentation.
Done.


diff --git a/drivers/phy/tegra/Makefile b/drivers/phy/tegra/Makefile
index 898589238fd9..f85b2c86643d 100644
--- a/drivers/phy/tegra/Makefile
+++ b/drivers/phy/tegra/Makefile
@@ -4,3 +4,4 @@ phy-tegra-xusb-y += xusb.o
phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_124_SOC) += xusb-tegra124.o
phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_132_SOC) += xusb-tegra124.o
phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_210_SOC) += xusb-tegra210.o
+obj-$(CONFIG_PHY_TEGRA194_PCIE_P2U) += pcie-p2u-tegra194.o
diff --git a/drivers/phy/tegra/pcie-p2u-tegra194.c b/drivers/phy/tegra/pcie-p2u-tegra194.c
new file mode 100644
index 000000000000..d4df8bfa9979
--- /dev/null
+++ b/drivers/phy/tegra/pcie-p2u-tegra194.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * P2U (PIPE to UPHY) driver for Tegra T194 SoC
+ *
+ * Copyright (C) 2019 NVIDIA Corporation.
+ *
+ * Author: Vidya Sagar <vidyas@xxxxxxxxxx>
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/of.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/of_platform.h>
+#include <soc/tegra/bpmp-abi.h>

It's a good idea to keep these sorted alphabetically. That makes it a
lot easier to insert new ones in the right place subsequently.
Done.


+
+#define P2U_PERIODIC_EQ_CTRL_GEN3 0xc0
+#define P2U_PERIODIC_EQ_CTRL_GEN3_PERIODIC_EQ_EN BIT(0)
+#define P2U_PERIODIC_EQ_CTRL_GEN3_INIT_PRESET_EQ_TRAIN_EN BIT(1)
+#define P2U_PERIODIC_EQ_CTRL_GEN4 0xc4
+#define P2U_PERIODIC_EQ_CTRL_GEN4_INIT_PRESET_EQ_TRAIN_EN BIT(1)
+
+#define P2U_RX_DEBOUNCE_TIME 0xa4
+#define P2U_RX_DEBOUNCE_TIME_DEBOUNCE_TIMER_MASK 0xFFFF

Use consistent case for hexadecimal. All other register definitions use
lower-case, so this one should, too.

+#define P2U_RX_DEBOUNCE_TIME_DEBOUNCE_TIMER_VAL 160
+
+struct tegra_p2u {
+ void __iomem *base;

I personally wouldn't bother with the extra padding. A single space is
enough and avoid extra churn if you ever add something here that doesn't
fit into the existing padding space.
Done.


+};
+
+static int tegra_p2u_power_on(struct phy *x)
+{
+ u32 val;
+ struct tegra_p2u *phy = phy_get_drvdata(x);

It's often common to structure these as "reverse christmas tree" so that
the longest lines go first, followed by shorter lines. Not sure if
Kishon cares, though.
Done. Took care of this in pcie-tegra194.c as well.


+
+ val = readl(phy->base + P2U_PERIODIC_EQ_CTRL_GEN3);
+ val &= ~P2U_PERIODIC_EQ_CTRL_GEN3_PERIODIC_EQ_EN;
+ val |= P2U_PERIODIC_EQ_CTRL_GEN3_INIT_PRESET_EQ_TRAIN_EN;
+ writel(val, phy->base + P2U_PERIODIC_EQ_CTRL_GEN3);
+
+ val = readl(phy->base + P2U_PERIODIC_EQ_CTRL_GEN4);
+ val |= P2U_PERIODIC_EQ_CTRL_GEN4_INIT_PRESET_EQ_TRAIN_EN;
+ writel(val, phy->base + P2U_PERIODIC_EQ_CTRL_GEN4);
+
+ val = readl(phy->base + P2U_RX_DEBOUNCE_TIME);
+ val &= ~P2U_RX_DEBOUNCE_TIME_DEBOUNCE_TIMER_MASK;
+ val |= P2U_RX_DEBOUNCE_TIME_DEBOUNCE_TIMER_VAL;
+ writel(val, phy->base + P2U_RX_DEBOUNCE_TIME);
+
+ return 0;
+}
+
+static const struct phy_ops ops = {
+ .power_on = tegra_p2u_power_on,
+ .owner = THIS_MODULE,
+};
+
+static int tegra_p2u_probe(struct platform_device *pdev)
+{
+ struct tegra_p2u *phy;
+ struct phy *generic_phy;
+ struct phy_provider *phy_provider;
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+
+ phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctl");
+ phy->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(phy->base))
+ return PTR_ERR_OR_ZERO(phy->base);
+
+ platform_set_drvdata(pdev, phy);
+
+ generic_phy = devm_phy_create(dev, NULL, &ops);
+ if (IS_ERR(generic_phy))
+ return PTR_ERR_OR_ZERO(generic_phy);
+
+ phy_set_drvdata(generic_phy, phy);
+
+ phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+ if (IS_ERR(phy_provider))
+ return PTR_ERR_OR_ZERO(phy_provider);
+
+ return 0;
+}
+
+static int tegra_p2u_remove(struct platform_device *pdev)
+{
+ return 0;
+}

I think you can drop this.
I want to make this as a loadable module hence i kep t .remove()
implementation.

+
+static const struct of_device_id tegra_p2u_id_table[] = {
+ {
+ .compatible = "nvidia,tegra194-p2u",
+ },
+ {}
+};
+MODULE_DEVICE_TABLE(of, tegra_p2u_id_table);
+
+static struct platform_driver tegra_p2u_driver = {
+ .probe = tegra_p2u_probe,
+ .remove = tegra_p2u_remove,
+ .driver = {
+ .name = "tegra194-p2u",
+ .of_match_table = tegra_p2u_id_table,
+ },
+};
+
+module_platform_driver(tegra_p2u_driver);
+
+MODULE_AUTHOR("Vidya Sagar <vidyas@xxxxxxxxxx>");
+MODULE_DESCRIPTION("NVIDIA Tegra PIPE_To_UPHY phy driver");

The driver description is somewhat odd here. Perhaps something like:

"NVIDIA Tegra PIPE to UPHY PHY driver"

?
Done.


Thierry

+MODULE_LICENSE("GPL v2");
--
2.7.4