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Message-ID: <f8f0ffb4-0d13-cd2a-f993-3b83adeb1375@nvidia.com>
Date: Tue, 16 Apr 2019 23:44:18 +0530
From: Vidya Sagar <vidyas@...dia.com>
To: Thierry Reding <thierry.reding@...il.com>
CC: <bhelgaas@...gle.com>, <robh+dt@...nel.org>,
<mark.rutland@....com>, <jonathanh@...dia.com>, <kishon@...com>,
<catalin.marinas@....com>, <will.deacon@....com>,
<lorenzo.pieralisi@....com>, <jingoohan1@...il.com>,
<gustavo.pimentel@...opsys.com>, <mperttunen@...dia.com>,
<linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <kthota@...dia.com>,
<mmaddireddy@...dia.com>, <sagar.tv@...il.com>
Subject: Re: [PATCH V2 14/16] phy: tegra: Add PCIe PIPE2UPHY support
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@...dia.com>
>> ---
>> 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@...dia.com>
>> + */
>> +
>> +#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@...dia.com>");
>> +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
>>
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