On 6/10/2019 5:24 PM, Dmitry Osipenko wrote:

07.06.2019 17:46, Vidya Sagar пишет:

quoted

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 <redacted>
---
Changes since [v8]:
* Made it dependent on ARCH_TEGRA_194_SOC directly instead of ARCH_TEGRA

Changes since [v7]:
* Changed P2U driver file name from pcie-p2u-tegra194.c to phy-tegra194-p2u.c

Changes since [v6]:
* None

Changes since [v5]:
* Addressed review comments from Thierry

Changes since [v4]:
* None

Changes since [v3]:
* Rebased on top of linux-next top of the tree

Changes since [v2]:
* Replaced spaces with tabs in Kconfig file
* Sorted header file inclusion alphabetically

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/phy-tegra194-p2u.c | 109 +++++++++++++++++++++++++++
  3 files changed, 117 insertions(+)
  create mode 100644 drivers/phy/tegra/phy-tegra194-p2u.c

diff --git a/drivers/phy/tegra/Kconfig b/drivers/phy/tegra/Kconfig
index e516967d695b..f9817c3ae85f 100644
--- a/drivers/phy/tegra/Kconfig
+++ b/drivers/phy/tegra/Kconfig

@@ -7,3 +7,10 @@ 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_P2U
+	tristate "NVIDIA Tegra194 PIPE2UPHY PHY driver"
+	depends on ARCH_TEGRA_194_SOC || COMPILE_TEST
+	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 64ccaeacb631..320dd389f34d 100644
--- a/drivers/phy/tegra/Makefile
+++ b/drivers/phy/tegra/Makefile

@@ -6,3 +6,4 @@ 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-$(CONFIG_ARCH_TEGRA_210_SOC) += xusb-tegra210.o
  phy-tegra-xusb-$(CONFIG_ARCH_TEGRA_186_SOC) += xusb-tegra186.o
+obj-$(CONFIG_PHY_TEGRA194_P2U) += phy-tegra194-p2u.o

diff --git a/drivers/phy/tegra/phy-tegra194-p2u.c b/drivers/phy/tegra/phy-tegra194-p2u.c
new file mode 100644
index 000000000000..7b84b4c55e43
--- /dev/null
+++ b/drivers/phy/tegra/phy-tegra194-p2u.c

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * P2U (PIPE to UPHY) driver for Tegra T194 SoC
+ *
+ * Copyright (C) 2019 NVIDIA Corporation.
+ *
+ * Author: Vidya Sagar <vidyas@nvidia.com>
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.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_on(struct phy *x)
+{
+	struct tegra_p2u *phy = phy_get_drvdata(x);
+	u32 val;
+
+	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);

I'm wondering whether you're really need to insert memory barriers for
each readl/writel, can't the relaxed versions be used instead?

Well, there is no real need to use readl/writel with their memory barriers.
I'll push new series replacing them with their _relaxed() counterparts.

The same applies to other patches as well.

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