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

[Vidya Sagar <vidyas@nvidia.com>]

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@nvidia.com>
>> ---
>>   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@nvidia.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>
>> +
>> +#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
>