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Date: Sat, 23 May 2015 12:52:21 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: Roger Quadros <rogerq@...com>, <tony@...mide.com>
CC: <nm@...com>, <nsekhar@...com>, <balbi@...com>,
<grygorii.strashko@...com>, <linux-kernel@...r.kernel.org>,
<linux-omap@...r.kernel.org>
Subject: Re: [PATCH 2/3] phy: ti-pipe3: i783 workaround for SATA lockup after
dpll unlock/relock
Roger,
On Friday 22 May 2015 07:28 PM, Roger Quadros wrote:
> Kishon,
>
> On 22/05/15 14:34, Kishon Vijay Abraham I wrote:
>> Roger,
>>
>> On Wednesday 20 May 2015 07:17 PM, Roger Quadros wrote:
>>> Kishon,
>>>
>>> On 20/05/15 16:19, Kishon Vijay Abraham I wrote:
>>>> Hi Roger,
>>>>
>>>> On Tuesday 12 May 2015 09:37 PM, Roger Quadros wrote:
>>>>> SATA_PLL_SOFT_RESET bit of CTRL_CORE_SMA_SW_0 must be toggled
>>>>> between a SATA DPLL unlock and re-lock to prevent SATA lockup.
>>>>>
>>>>> Introduce a new DT parameter 'syscon-pllreset' to provide the syscon
>>>>> regmap access to this register which sits in the control module.
>>>>>
>>>>> If the register is not provided we fallback to the old behaviour
>>>>> i.e. SATA DPLL refclk will not be disabled and we prevent SoC low
>>>>> power states.
>>>>>
>>>>> Signed-off-by: Roger Quadros <rogerq@...com>
>>>>> ---
>>>>> Documentation/devicetree/bindings/phy/ti-phy.txt | 16 ++++++
>>>>> drivers/phy/phy-ti-pipe3.c | 67
>>>>> ++++++++++++++++++++----
>>>>> 2 files changed, 74 insertions(+), 9 deletions(-)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/phy/ti-phy.txt
>>>>> b/Documentation/devicetree/bindings/phy/ti-phy.txt
>>>>> index 305e3df..f0f5537 100644
>>>>> --- a/Documentation/devicetree/bindings/phy/ti-phy.txt
>>>>> +++ b/Documentation/devicetree/bindings/phy/ti-phy.txt
>>>>> @@ -82,6 +82,9 @@ Optional properties:
>>>>> - id: If there are multiple instance of the same type, in order to
>>>>> differentiate between each instance "id" can be used (e.g.,
>>>>> multi-lane PCIe
>>>>> PHY). If "id" is not provided, it is set to default value of '1'.
>>>>> + - syscon-pllreset: Handle to system control region that contains the
>>>>> + CTRL_CORE_SMA_SW_0 register and register offset to the
>>>>> CTRL_CORE_SMA_SW_0
>>>>> + register that contains the SATA_PLL_SOFT_RESET bit. Only valid for
>>>>> sata_phy.
>>>>>
>>>>> This is usually a subnode of ocp2scp to which it is connected.
>>>>>
>>>>> @@ -100,3 +103,16 @@ usb3phy@...84400 {
>>>>> "sysclk",
>>>>> "refclk";
>>>>> };
>>>>> +
>>>>> +sata_phy: phy@...96000 {
>>>>> + compatible = "ti,phy-pipe3-sata";
>>>>> + reg = <0x4A096000 0x80>, /* phy_rx */
>>>>> + <0x4A096400 0x64>, /* phy_tx */
>>>>> + <0x4A096800 0x40>; /* pll_ctrl */
>>>>> + reg-names = "phy_rx", "phy_tx", "pll_ctrl";
>>>>> + ctrl-module = <&omap_control_sata>;
>>>>> + clocks = <&sys_clkin1>, <&sata_ref_clk>;
>>>>> + clock-names = "sysclk", "refclk";
>>>>> + syscon-pllreset = <&dra7_ctrl_core 0x3fc>;
>>>>> + #phy-cells = <0>;
>>>>> +};
>>>>> diff --git a/drivers/phy/phy-ti-pipe3.c b/drivers/phy/phy-ti-pipe3.c
>>>>> index e13a306..d730142 100644
>>>>> --- a/drivers/phy/phy-ti-pipe3.c
>>>>> +++ b/drivers/phy/phy-ti-pipe3.c
>>>>> @@ -28,6 +28,8 @@
>>>>> #include <linux/delay.h>
>>>>> #include <linux/phy/omap_control_phy.h>
>>>>> #include <linux/of_platform.h>
>>>>> +#include <linux/mfd/syscon.h>
>>>>> +#include <linux/regmap.h>
>>>>>
>>>>> #define PLL_STATUS 0x00000004
>>>>> #define PLL_GO 0x00000008
>>>>> @@ -52,6 +54,8 @@
>>>>> #define PLL_LOCK 0x2
>>>>> #define PLL_IDLE 0x1
>>>>>
>>>>> +#define SATA_PLL_SOFT_RESET BIT(18)
>>>>> +
>>>>> /*
>>>>> * This is an Empirical value that works, need to confirm the actual
>>>>> * value required for the PIPE3PHY_PLL_CONFIGURATION2.PLL_IDLE status
>>>>> @@ -82,6 +86,9 @@ struct ti_pipe3 {
>>>>> struct clk *refclk;
>>>>> struct clk *div_clk;
>>>>> struct pipe3_dpll_map *dpll_map;
>>>>> + struct regmap *dpll_reset_syscon; /* ctrl. reg. acces */
>>>>> + unsigned int dpll_reset_reg; /* reg. index within syscon */
>>>>> + bool sata_refclk_enabled;
>>>>> };
>>>>>
>>>>> static struct pipe3_dpll_map dpll_map_usb[] = {
>>>>> @@ -249,11 +256,15 @@ static int ti_pipe3_exit(struct phy *x)
>>>>> u32 val;
>>>>> unsigned long timeout;
>>>>>
>>>>> - /* SATA DPLL can't be powered down due to Errata i783 and PCIe
>>>>> - * does not have internal DPLL
>>>>> + /* If dpll_reset_syscon is not present we wont power down SATA DPLL
>>>>> + * due to Errata i783
>>>>> */
>>>>> - if (of_device_is_compatible(phy->dev->of_node,
>>>>> "ti,phy-pipe3-sata") ||
>>>>> - of_device_is_compatible(phy->dev->of_node, "ti,phy-pipe3-pcie"))
>>>>> + if (of_device_is_compatible(phy->dev->of_node,
>>>>> "ti,phy-pipe3-sata") &&
>>>>> + !phy->dpll_reset_syscon)
>>>>> + return 0;
>>>>> +
>>>>> + /* PCIe doesn't have DPLL. FIXME: need to disable clocks though */
>>>>
>>>> I think it's better to fix it in this patch itself.. to disable clocks
>>>> for PCIe.
>>>>> + if (of_device_is_compatible(phy->dev->of_node, "ti,phy-pipe3-pcie"))
>>>>> return 0;
>>>>>
>>>>> /* Put DPLL in IDLE mode */
>>>>> @@ -276,6 +287,14 @@ static int ti_pipe3_exit(struct phy *x)
>>>>> return -EBUSY;
>>>>> }
>>>>>
>>>>> + /* i783: SATA needs control bit toggle after PLL unlock */
>>>>> + if (of_device_is_compatible(phy->dev->of_node,
>>>>> "ti,phy-pipe3-sata")) {
>>>>> + regmap_update_bits(phy->dpll_reset_syscon, phy->dpll_reset_reg,
>>>>> + SATA_PLL_SOFT_RESET, SATA_PLL_SOFT_RESET);
>>>>> + regmap_update_bits(phy->dpll_reset_syscon, phy->dpll_reset_reg,
>>>>> + SATA_PLL_SOFT_RESET, 0);
>>>>> + }
>>>>> +
>>>>> ti_pipe3_disable_clocks(phy);
>>>>>
>>>>> return 0;
>>>>> @@ -350,6 +369,21 @@ static int ti_pipe3_probe(struct platform_device
>>>>> *pdev)
>>>>> }
>>>>> } else {
>>>>> phy->wkupclk = ERR_PTR(-ENODEV);
>>>>> + phy->dpll_reset_syscon = syscon_regmap_lookup_by_phandle(node,
>>>>> + "syscon-pllreset");
>>>>> + if (IS_ERR(phy->dpll_reset_syscon)) {
>>>>> + dev_info(&pdev->dev,
>>>>> + "can't get syscon-pllreset, sata dpll won't idle\n");
>>>>> + phy->dpll_reset_syscon = NULL;
>>>>> + } else {
>>>>> + if (of_property_read_u32_index(node,
>>>>> + "syscon-pllreset", 1,
>>>>> + &phy->dpll_reset_reg)) {
>>>>> + dev_err(&pdev->dev,
>>>>> + "couldn't get pllreset reg. offset\n");
>>>>> + return -EINVAL;
>>>>> + }
>>>>> + }
>>>>> }
>>>>>
>>>>> if (of_device_is_compatible(node, "ti,phy-pipe3-pcie")) {
>>>>> @@ -402,9 +436,16 @@ static int ti_pipe3_probe(struct platform_device
>>>>> *pdev)
>>>>>
>>>>> platform_set_drvdata(pdev, phy);
>>>>> pm_runtime_enable(phy->dev);
>>>>> - /* Prevent auto-disable of refclk for SATA PHY due to Errata i783 */
>>>>> - if (of_device_is_compatible(node, "ti,phy-pipe3-sata"))
>>>>> - clk_prepare_enable(phy->refclk);
>>>>> +
>>>>> + /*
>>>>> + * Prevent auto-disable of refclk for SATA PHY due to Errata i783
>>>>> + */
>>>>> + if (of_device_is_compatible(node, "ti,phy-pipe3-sata")) {
>>>>> + if (!IS_ERR(phy->refclk)) {
>>>>> + clk_prepare_enable(phy->refclk);
>>>>> + phy->sata_refclk_enabled = true;
>>>>> + }
>>>>> + }
>>>>>
>>>>> generic_phy = devm_phy_create(phy->dev, NULL, &ops);
>>>>> if (IS_ERR(generic_phy))
>>>>> @@ -443,8 +484,17 @@ static int ti_pipe3_enable_refclk(struct ti_pipe3
>>>>> *phy)
>>>>>
>>>>> static void ti_pipe3_disable_refclk(struct ti_pipe3 *phy)
>>>>> {
>>>>> - if (!IS_ERR(phy->refclk))
>>>>> + if (!IS_ERR(phy->refclk)) {
>>>>> clk_disable_unprepare(phy->refclk);
>>>>> + /*
>>>>> + * SATA refclk needs an additional disable as we left it
>>>>> + * on in probe to avoid Errata i783
>>>>
>>>> not sure I get this. Why don't we remove it in probe?
>>>
>>> Because if we remove it from probe and if AHCI_PLATFORM is built as a
>>> module then phy_init won't be called before kernel starts autodisabling
>>> unused clocks and so SATA refclk gets disabled causing i783 and
>>> breaking SATA.
>>
>> Just to be clear, this entire thing won't be required if uboot does SATA_PLL_SOFT_RESET no?
>>
>
> Yes that is right. We don't yet have the u-boot fix and there is no guarantee all users move
> to the u-boot with the fix, so this is important.
Okay. Just thinking if we can do SATA_PLL_SOFT_RESET in probe to begin with.
That way we don't have to do this additional clk_enable().
Thanks
Kishon
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