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SubjectRe: [PATCH 3/3] phy: ti: Add a new SERDES driver for TI's AM654x SoC
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Date
Hi Kishon,

On 21/01/19 08:48, Kishon Vijay Abraham I wrote:
> Add a new SERDES driver for TI's AM654x SoC which configures
> the SERDES only for PCIe. Support fo USB3 will be added later.
>
> SERDES in am654x has three input clocks (left input, externel reference
> clock and right input) and two output clocks (left output and right
> output) in addition to a PLL mux clock which the SERDES uses for Clock
> Multiplier Unit (CMU refclock).
>
> The PLL mux clock can select from one of the three input clocks.
> The right output can select between left input and external reference
> clock while the left output can select between the right input and
> external reference clock.
>
> The driver has support to select PLL mux and left/right output mux as
> specified in device tree.
>
> [rogerq@ti.com: Fix boot lockup caused by accessing a structure member
> (hw->init) allocated in stack of probe() and accessed in get_parent]
> [rogerq@ti.com: Fix "Failed to find the parent" warnings]
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
> ---
> drivers/phy/ti/Kconfig | 11 +
> drivers/phy/ti/Makefile | 1 +
> drivers/phy/ti/phy-am654-serdes.c | 528 ++++++++++++++++++++++++++++++
> 3 files changed, 540 insertions(+)
> create mode 100644 drivers/phy/ti/phy-am654-serdes.c
>
> diff --git a/drivers/phy/ti/Kconfig b/drivers/phy/ti/Kconfig
> index f137e0107764..6357c32de115 100644
> --- a/drivers/phy/ti/Kconfig
> +++ b/drivers/phy/ti/Kconfig
> @@ -20,6 +20,17 @@ config PHY_DM816X_USB
> help
> Enable this for dm816x USB to work.
>
> +config PHY_AM654_SERDES
> + tristate "TI AM654 SERDES support"
> + depends on OF && ARCH_K3 || COMPILE_TEST
> + select GENERIC_PHY
> + select MULTIPLEXER
> + select REGMAP_MMIO
> + select MUX_MMIO
> + help
> + This option enables support for TI AM654 SerDes PHY used for
> + PCIe.
> +
> config OMAP_CONTROL_PHY
> tristate "OMAP CONTROL PHY Driver"
> depends on ARCH_OMAP2PLUS || COMPILE_TEST
> diff --git a/drivers/phy/ti/Makefile b/drivers/phy/ti/Makefile
> index bea8f25a137a..bff901eb0ecc 100644
> --- a/drivers/phy/ti/Makefile
> +++ b/drivers/phy/ti/Makefile
> @@ -6,4 +6,5 @@ obj-$(CONFIG_OMAP_USB2) += phy-omap-usb2.o
> obj-$(CONFIG_TI_PIPE3) += phy-ti-pipe3.o
> obj-$(CONFIG_PHY_TUSB1210) += phy-tusb1210.o
> obj-$(CONFIG_TWL4030_USB) += phy-twl4030-usb.o
> +obj-$(CONFIG_PHY_AM654_SERDES) += phy-am654-serdes.o
> obj-$(CONFIG_PHY_TI_GMII_SEL) += phy-gmii-sel.o
> diff --git a/drivers/phy/ti/phy-am654-serdes.c b/drivers/phy/ti/phy-am654-serdes.c
> new file mode 100644
> index 000000000000..fcc0a98fbbd3
> --- /dev/null
> +++ b/drivers/phy/ti/phy-am654-serdes.c
> @@ -0,0 +1,528 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * PCIe SERDES driver for AM654x SoC
> + *
> + * Copyright (C) 2018 Texas Instruments
> + * Author: Kishon Vijay Abraham I <kishon@ti.com>
> + */
> +
> +#include <dt-bindings/phy/phy.h>
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mux/consumer.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +
> +#define CMU_R07C 0x7c
> +#define CMU_MASTER_CDN_O BIT(24)
> +
> +#define COMLANE_R138 0xb38
> +#define CONFIG_VERSION_REG_MASK GENMASK(23, 16)
> +#define CONFIG_VERSION_REG_SHIFT 16
> +#define VERSION 0x70
> +
> +#define COMLANE_R190 0xb90
> +#define L1_MASTER_CDN_O BIT(9)
> +
> +#define COMLANE_R194 0xb94
> +#define CMU_OK_I_0 BIT(19)
> +
> +#define SERDES_CTRL 0x1fd0
> +#define POR_EN BIT(29)
> +
> +#define WIZ_LANEXCTL_STS 0x1fe0
> +#define TX0_ENABLE_OVL BIT(31)
> +#define TX0_ENABLE_MASK GENMASK(30, 29)
> +#define TX0_ENABLE_SHIFT 29
> +#define TX0_DISABLE_STATE 0x0
> +#define TX0_SLEEP_STATE 0x1
> +#define TX0_SNOOZE_STATE 0x2
> +#define TX0_ENABLE_STATE 0x3
> +#define RX0_ENABLE_OVL BIT(15)
> +#define RX0_ENABLE_MASK GENMASK(14, 13)
> +#define RX0_ENABLE_SHIFT 13
> +#define RX0_DISABLE_STATE 0x0
> +#define RX0_SLEEP_STATE 0x1
> +#define RX0_SNOOZE_STATE 0x2
> +#define RX0_ENABLE_STATE 0x3
> +
> +#define WIZ_PLL_CTRL 0x1ff4
> +#define PLL_ENABLE_OVL BIT(31)
> +#define PLL_ENABLE_MASK GENMASK(30, 29)
> +#define PLL_ENABLE_SHIFT 29
> +#define PLL_DISABLE_STATE 0x0
> +#define PLL_SLEEP_STATE 0x1
> +#define PLL_SNOOZE_STATE 0x2
> +#define PLL_ENABLE_STATE 0x3
> +#define PLL_OK BIT(28)
> +
> +#define PLL_LOCK_TIME 100000 /* in microseconds */
> +#define SLEEP_TIME 100 /* in microseconds */
> +
> +#define LANE_USB3 0x0
> +#define LANE_PCIE0_LANE0 0x1
> +
> +#define LANE_PCIE1_LANE0 0x0
> +#define LANE_PCIE0_LANE1 0x1
> +
> +#define SERDES_NUM_CLOCKS 3
> +
> +struct serdes_am654_clk_mux {
> + struct clk_hw hw;
> + struct regmap *regmap;
> + unsigned int reg;
> + int *table;
> + u32 mask;
> + u8 shift;
> + struct clk_init_data clk_data;
> +};
> +
> +#define to_serdes_am654_clk_mux(_hw) \
> + container_of(_hw, struct serdes_am654_clk_mux, hw)
> +
> +static struct regmap_config serdes_am654_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + .fast_io = true,
> +};
> +
> +struct serdes_am654 {
> + struct regmap *regmap;
> + struct device *dev;
> + struct mux_control *control;
> + bool busy;
> + u32 type;
> + struct device_node *of_node;
> + struct clk_onecell_data clk_data;
> + struct clk *clks[SERDES_NUM_CLOCKS];
> +};
> +
> +static int serdes_am654_enable_pll(struct serdes_am654 *phy)
> +{
> + u32 mask = PLL_ENABLE_OVL | PLL_ENABLE_MASK;
> + u32 val = PLL_ENABLE_OVL | (PLL_ENABLE_STATE << PLL_ENABLE_SHIFT);
> +
> + regmap_update_bits(phy->regmap, WIZ_PLL_CTRL, mask, val);
> +
> + return regmap_read_poll_timeout(phy->regmap, WIZ_PLL_CTRL, val,
> + val & PLL_OK, 1000, PLL_LOCK_TIME);
> +}
> +
> +static void serdes_am654_disable_pll(struct serdes_am654 *phy)
> +{
> + u32 mask = PLL_ENABLE_OVL | PLL_ENABLE_MASK;
> +
> + regmap_update_bits(phy->regmap, WIZ_PLL_CTRL, mask, 0);

Shouldn't PLL_ENABLE_OVL be left set otherwise override mechanism won't work?

So,

regmap_update_bits(phy->regmap, WIZ_PLL_CTRL, mask, PLL_ENABLE_OVL);

> +}
> +
> +static int serdes_am654_enable_txrx(struct serdes_am654 *phy)
> +{
> + u32 mask;
> + u32 val;
> +
> + /* Enable TX */
> + mask = TX0_ENABLE_OVL | TX0_ENABLE_MASK;
> + val = TX0_ENABLE_OVL | (TX0_ENABLE_STATE << TX0_ENABLE_SHIFT);
> + regmap_update_bits(phy->regmap, WIZ_LANEXCTL_STS, mask, val);
> +
> + /* Enable RX */
> + mask = RX0_ENABLE_OVL | RX0_ENABLE_MASK;
> + val = RX0_ENABLE_OVL | (RX0_ENABLE_STATE << RX0_ENABLE_SHIFT);
> + regmap_update_bits(phy->regmap, WIZ_LANEXCTL_STS, mask, val);
> +
> + return 0;
> +}
> +
> +static int serdes_am654_disable_txrx(struct serdes_am654 *phy)
> +{
> + u32 mask;
> +
> + /* Disable TX */
> + mask = TX0_ENABLE_OVL | TX0_ENABLE_MASK;
> + regmap_update_bits(phy->regmap, WIZ_LANEXCTL_STS, mask, 0);

Here too.
> +
> + /* Disable RX */
> + mask = RX0_ENABLE_OVL | RX0_ENABLE_MASK;
> + regmap_update_bits(phy->regmap, WIZ_LANEXCTL_STS, mask, 0);

Here as well.

> +
> + return 0;
> +}
> +
> +static int serdes_am654_power_on(struct phy *x)
> +{
> + struct serdes_am654 *phy = phy_get_drvdata(x);
> + struct device *dev = phy->dev;
> + int ret;
> + u32 val;
> +
> + ret = serdes_am654_enable_pll(phy);
> + if (ret) {
> + dev_err(dev, "Failed to enable PLL\n");
> + return ret;
> + }
> +
> + ret = serdes_am654_enable_txrx(phy);
> + if (ret) {
> + dev_err(dev, "Failed to enable TX RX\n");
> + return ret;
> + }
> +
> + return regmap_read_poll_timeout(phy->regmap, COMLANE_R194, val,
> + val & CMU_OK_I_0, SLEEP_TIME,
> + PLL_LOCK_TIME);
> +}
> +
> +static int serdes_am654_power_off(struct phy *x)
> +{
> + struct serdes_am654 *phy = phy_get_drvdata(x);
> +
> + serdes_am654_disable_txrx(phy);
> + serdes_am654_disable_pll(phy);
> +
> + return 0;
> +}
> +
> +static int serdes_am654_init(struct phy *x)
> +{
> + struct serdes_am654 *phy = phy_get_drvdata(x);
> + u32 mask;
> + u32 val;
> +
> + mask = CONFIG_VERSION_REG_MASK;
> + val = VERSION << CONFIG_VERSION_REG_SHIFT;
> + regmap_update_bits(phy->regmap, COMLANE_R138, mask, val);
> +
> + val = CMU_MASTER_CDN_O;
> + regmap_update_bits(phy->regmap, CMU_R07C, val, val);
> +
> + val = L1_MASTER_CDN_O;
> + regmap_update_bits(phy->regmap, COMLANE_R190, val, val);
> +
> + return 0;
> +}
> +
> +static int serdes_am654_reset(struct phy *x)
> +{
> + struct serdes_am654 *phy = phy_get_drvdata(x);
> + u32 val;
> +
> + val = POR_EN;
> + regmap_update_bits(phy->regmap, SERDES_CTRL, val, val);
> + mdelay(1);
> + regmap_update_bits(phy->regmap, SERDES_CTRL, val, 0);
> +
> + return 0;
> +}
> +
> +struct phy *serdes_am654_xlate(struct device *dev, struct of_phandle_args
> + *args)
> +{
> + struct serdes_am654 *am654_phy;
> + struct phy *phy;
> + int ret;
> +
> + phy = of_phy_simple_xlate(dev, args);
> + if (IS_ERR(phy))
> + return phy;
> +
> + am654_phy = phy_get_drvdata(phy);
> + if (am654_phy->type != args->args[0] && am654_phy->busy)
> + return ERR_PTR(-EBUSY);

You set the busy flag in this function but it is never cleared.
This means the second phy_get() will always fail. We might get into this
situation for example if the driver doing the phy_get() had to bail out
due to some reason (e.g. -EPROBE_DEFER), and gets probed again and does
a phy_get() a second time for the same PHY and lane.

Can we clear the busy flag and call mux_control_deselect() on phy_put()?

cheers,
-roger

> +
> + ret = mux_control_select(am654_phy->control, args->args[1]);
> + if (ret) {
> + dev_err(dev, "Failed to select SERDES Lane Function\n");
> + return ERR_PTR(ret);
> + }
> +
> + am654_phy->busy = true;
> + am654_phy->type = args->args[0];
> +
> + return phy;
> +}
> +
> +static const struct phy_ops ops = {
> + .reset = serdes_am654_reset,
> + .init = serdes_am654_init,
> + .power_on = serdes_am654_power_on,
> + .power_off = serdes_am654_power_off,
> + .owner = THIS_MODULE,
> +};
> +
> +static u8 serdes_am654_clk_mux_get_parent(struct clk_hw *hw)
> +{
> + struct serdes_am654_clk_mux *mux = to_serdes_am654_clk_mux(hw);
> + unsigned int num_parents = clk_hw_get_num_parents(hw);
> + struct regmap *regmap = mux->regmap;
> + unsigned int reg = mux->reg;
> + unsigned int val;
> + int i;
> +
> + regmap_read(regmap, reg, &val);
> + val >>= mux->shift;
> + val &= mux->mask;
> +
> + for (i = 0; i < num_parents; i++)
> + if (mux->table[i] == val)
> + return i;
> +
> + /*
> + * No parent? This should never happen!
> + * Verify if we set a valid parent in serdes_am654_clk_register()
> + */
> + WARN(1, "Failed to find the parent of %s clock\n", hw->init->name);
> +
> + /* Make the parent lookup to fail */
> + return num_parents;
> +}
> +
> +static int serdes_am654_clk_mux_set_parent(struct clk_hw *hw, u8 index)
> +{
> + struct serdes_am654_clk_mux *mux = to_serdes_am654_clk_mux(hw);
> + struct regmap *regmap = mux->regmap;
> + unsigned int reg = mux->reg;
> + int val;
> + int ret;
> +
> + val = mux->table[index];
> +
> + if (val == -1)
> + return -EINVAL;
> +
> + val <<= mux->shift;
> + ret = regmap_update_bits(regmap, reg, mux->mask << mux->shift, val);
> +
> + return ret;
> +}
> +
> +static const struct clk_ops serdes_am654_clk_mux_ops = {
> + .set_parent = serdes_am654_clk_mux_set_parent,
> + .get_parent = serdes_am654_clk_mux_get_parent,
> +};
> +
> +static int mux_table[SERDES_NUM_CLOCKS][3] = {
> + /*
> + * The entries represent values for selecting between
> + * {left input, external reference clock, right input}
> + * Only one of Left Output or Right Output should be used since
> + * both left and right output clock uses the same bits and modifying
> + * one clock will impact the other.
> + */
> + { BIT(2), 0, BIT(0) }, /* Mux of CMU refclk */
> + { -1, BIT(3), BIT(1) }, /* Mux of Left Output */
> + { BIT(1), BIT(3) | BIT(1), -1 }, /* Mux of Right Output */
> +};
> +
> +static int mux_mask[SERDES_NUM_CLOCKS] = { 0x5, 0xa, 0xa };
> +
> +static int serdes_am654_clk_register(struct serdes_am654 *am654_phy,
> + const char *clock_name, int clock_num)
> +{
> + struct device_node *node = am654_phy->of_node;
> + struct device *dev = am654_phy->dev;
> + struct serdes_am654_clk_mux *mux;
> + struct device_node *regmap_node;
> + const char **parent_names;
> + struct clk_init_data *init;
> + unsigned int num_parents;
> + struct regmap *regmap;
> + const __be32 *addr;
> + unsigned int reg;
> + struct clk *clk;
> +
> + mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
> + if (!mux)
> + return -ENOMEM;
> +
> + init = &mux->clk_data;
> +
> + regmap_node = of_parse_phandle(node, "ti,serdes-clk", 0);
> + of_node_put(regmap_node);
> + if (!regmap_node) {
> + dev_err(dev, "Fail to get serdes-clk node\n");
> + return -ENODEV;
> + }
> +
> + regmap = syscon_node_to_regmap(regmap_node->parent);
> + if (IS_ERR(regmap)) {
> + dev_err(dev, "Fail to get Syscon regmap\n");
> + return PTR_ERR(regmap);
> + }
> +
> + num_parents = of_clk_get_parent_count(node);
> + if (num_parents < 3) {
> + dev_err(dev, "SERDES clock must have parents\n");
> + return -EINVAL;
> + }
> +
> + parent_names = devm_kzalloc(dev, (sizeof(char *) * num_parents),
> + GFP_KERNEL);
> + if (!parent_names)
> + return -ENOMEM;
> +
> + of_clk_parent_fill(node, parent_names, num_parents);
> +
> + addr = of_get_address(regmap_node, 0, NULL, NULL);
> + if (!addr)
> + return -EINVAL;
> +
> + reg = be32_to_cpu(*addr);
> +
> + init->ops = &serdes_am654_clk_mux_ops;
> + init->flags = CLK_SET_RATE_NO_REPARENT;
> + init->parent_names = parent_names;
> + init->num_parents = num_parents;
> + init->name = clock_name;
> +
> + mux->table = mux_table[clock_num];
> + mux->regmap = regmap;
> + mux->reg = reg;
> + mux->shift = 4;
> + mux->mask = mux_mask[clock_num];
> + mux->hw.init = init;
> +
> + /*
> + * setup a sane default so get_parent() call evaluates
> + * to a valid parent. Index 1 is the safest choice as
> + * the default as it is valid value for all of serdes's
> + * output clocks.
> + */
> + serdes_am654_clk_mux_set_parent(&mux->hw, 1);
> + clk = devm_clk_register(dev, &mux->hw);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + am654_phy->clks[clock_num] = clk;
> +
> + return 0;
> +}
> +
> +static const struct of_device_id serdes_am654_id_table[] = {
> + {
> + .compatible = "ti,phy-am654-serdes",
> + },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, serdes_am654_id_table);
> +
> +static int serdes_am654_probe(struct platform_device *pdev)
> +{
> + struct phy_provider *phy_provider;
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct clk_onecell_data *clk_data;
> + struct serdes_am654 *am654_phy;
> + struct mux_control *control;
> + const char *clock_name;
> + struct regmap *regmap;
> + struct resource *res;
> + void __iomem *base;
> + struct phy *phy;
> + int ret;
> + int i;
> +
> + am654_phy = devm_kzalloc(dev, sizeof(*am654_phy), GFP_KERNEL);
> + if (!am654_phy)
> + return -ENOMEM;
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "serdes");
> + base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + regmap = devm_regmap_init_mmio(dev, base, &serdes_am654_regmap_config);
> + if (IS_ERR(regmap)) {
> + dev_err(dev, "Failed to initialize regmap\n");
> + return PTR_ERR(regmap);
> + }
> +
> + control = devm_mux_control_get(dev, NULL);
> + if (IS_ERR(control))
> + return PTR_ERR(control);
> +
> + am654_phy->dev = dev;
> + am654_phy->of_node = node;
> + am654_phy->regmap = regmap;
> + am654_phy->control = control;
> +
> + platform_set_drvdata(pdev, am654_phy);
> +
> + for (i = 0; i < SERDES_NUM_CLOCKS; i++) {
> + ret = of_property_read_string_index(node, "clock-output-names",
> + i, &clock_name);
> + if (ret) {
> + dev_err(dev, "Failed to get clock name\n");
> + return ret;
> + }
> +
> + ret = serdes_am654_clk_register(am654_phy, clock_name, i);
> + if (ret) {
> + dev_err(dev, "Failed to initialize clock %s\n",
> + clock_name);
> + return ret;
> + }
> + }
> +
> + clk_data = &am654_phy->clk_data;
> + clk_data->clks = am654_phy->clks;
> + clk_data->clk_num = SERDES_NUM_CLOCKS;
> + ret = of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
> + if (ret)
> + return ret;
> +
> + pm_runtime_enable(dev);
> +
> + phy = devm_phy_create(dev, NULL, &ops);
> + if (IS_ERR(phy))
> + return PTR_ERR(phy);
> +
> + phy_set_drvdata(phy, am654_phy);
> + phy_provider = devm_of_phy_provider_register(dev, serdes_am654_xlate);
> + if (IS_ERR(phy_provider)) {
> + ret = PTR_ERR(phy_provider);
> + goto clk_err;
> + }
> +
> + return 0;
> +
> +clk_err:
> + of_clk_del_provider(node);
> +
> + return ret;
> +}
> +
> +static int serdes_am654_remove(struct platform_device *pdev)
> +{
> + struct serdes_am654 *am654_phy = platform_get_drvdata(pdev);
> + struct device_node *node = am654_phy->of_node;
> +
> + pm_runtime_disable(&pdev->dev);
> + of_clk_del_provider(node);
> +
> + return 0;
> +}
> +
> +static struct platform_driver serdes_am654_driver = {
> + .probe = serdes_am654_probe,
> + .remove = serdes_am654_remove,
> + .driver = {
> + .name = "phy-am654",
> + .of_match_table = serdes_am654_id_table,
> + },
> +};
> +module_platform_driver(serdes_am654_driver);
> +
> +MODULE_ALIAS("platform:phy-am654");
> +MODULE_AUTHOR("Texas Instruments Inc.");
> +MODULE_DESCRIPTION("TI AM654x SERDES driver");
> +MODULE_LICENSE("GPL v2");
>

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