Re: [PATCH 08/10] phy: tegra: Add PCIe PIPE2UPHY support

From: Vidya Sagar
Date: Wed Apr 03 2019 - 06:45:44 EST

On 4/3/2019 1:35 PM, Kishon Vijay Abraham I wrote:
Hi,

On 26/03/19 8:43 PM, 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>
---
drivers/phy/tegra/Kconfig | 7 ++
drivers/phy/tegra/Makefile | 1 +
drivers/phy/tegra/pcie-p2u-tegra194.c | 138 ++++++++++++++++++++++++++++++++++
3 files changed, 146 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..1460c060fa70 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
Done.

+ select GENERIC_PHY
+ help
+ Enable this to support the P2U (PIPE to UPHY) that is part of Tegra 19x SOCs.
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..bb2412ec4765
--- /dev/null
+++ b/drivers/phy/tegra/pcie-p2u-tegra194.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * P2U (PIPE to UPHY) driver for Tegra T194 SoC
+ *
+ * Copyright (C) 2018 NVIDIA Corporation.

2019
Done.

+ *
+ * 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>
+
+#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
+#define P2U_RX_DEBOUNCE_TIME_DEBOUNCE_TIMER_VAL 160
+
+struct tegra_p2u {
+ void __iomem *base;
+};
+
+static int tegra_p2u_power_off(struct phy *x)
+{
+ return 0;

Empty phy_ops are not required.
Done.

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

This looks more like a init configuration rather than power on.
+
+ return 0;
+}
+
+static int tegra_p2u_init(struct phy *x)
+{
+ return 0;
+}
+
+static int tegra_p2u_exit(struct phy *x)
+{
+ return 0;
+}

Empty functions are not required.
Done.

+
+static const struct phy_ops ops = {
+ .init = tegra_p2u_init,
+ .exit = tegra_p2u_exit,
+ .power_on = tegra_p2u_power_on,
+ .power_off = tegra_p2u_power_off,
+ .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, "base");
+ phy->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(phy->base))
+ return PTR_ERR(phy->base);
+
+ platform_set_drvdata(pdev, phy);
+
+ generic_phy = devm_phy_create(dev, NULL, &ops);
+ if (IS_ERR(generic_phy))
+ return PTR_ERR(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(phy_provider);
+

return PTR_ERR_OR_ZERO(phy_provider);
Done.

+ return 0;
+}
+
+static int tegra_p2u_remove(struct platform_device *pdev)
+{
+ return 0;
+}

not required.
I think this is still required as this driver can be made as a module right?


Thanks
Kishon