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Message-ID: <6aada109-0320-3c9b-7ded-9095ddaed90c@nvidia.com>
Date: Fri, 4 Sep 2020 17:10:49 +0800
From: JC Kuo <jckuo@...dia.com>
To: Thierry Reding <thierry.reding@...il.com>
CC: <gregkh@...uxfoundation.org>, <robh@...nel.org>,
<jonathanh@...dia.com>, <kishon@...com>,
<linux-tegra@...r.kernel.org>, <linux-usb@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<nkristam@...dia.com>
Subject: Re: [PATCH v2 03/12] phy: tegra: xusb: t210: rearrange UPHY init
Hi Thierry,
Thanks for review.
On 8/31/20 7:42 PM, Thierry Reding wrote:
> Please start commit subjects with a capital letter after the prefix.
> Also, please avoid t210 as abbreviation and use tegra210 instead.
>
> The above should be something like:
>
> phy: tegra: xusb: tegra210: Rearrange UPHY init
>
> Or perhaps:
>
> phy: tegra: xusb: Rearrange UPHY init on Tegra210
I will take this one. Thanks.
>
> On Mon, Aug 31, 2020 at 12:40:34PM +0800, JC Kuo wrote:
>> This commit is a preparation for enabling XUSB SC7 support.
>> It rearranges Tegra210 XUSB PADCTL UPHY initialization sequence,
>> for the following reasons:
>>
>> 1. PLLE hardware power sequencer has to be enabled only after both
>> PEX UPHY PLL and SATA UPHY PLL are initialized.
>> tegra210_uphy_init() -> tegra210_pex_uphy_enable()
>> -> tegra210_sata_uphy_enable()
>> -> tegra210_plle_hw_sequence_start()
>> -> tegra210_aux_mux_lp0_clamp_disable()
>>
>> 2. Once UPHY PLL hardware power sequencer is enabled, do not assert
>> reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be
>> broken.
>> reset_control_assert(pcie->rst) and reset_control_assert(sata->rst)
>> are removed from PEX/SATA UPHY disable procedure.
>>
>> 3. At cold boot and SC7 exit, the following bits must be cleared after
>> PEX/SATA lanes are out of IDDQ (IDDQ_DISABLE=1).
>> a. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN,
>> b. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN_EARLY
>> c. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_VCORE_DOWN
>>
>> tegra210_pex_uphy_enable() and tegra210_sata_uphy_enable() are in
>> charge of bringing lanes out of IDDQ, and then AUX_MUX_LP0_* bits
>> will be cleared by tegra210_aux_mux_lp0_clamp_disable().
>>
>> 4. The programming sequence in tegra210_usb3_port_enable() is required
>> for both cold boot and SC7 exit, and must be performed only after
>> PEX/SATA UPHY is initialized. Therefore, this commit moves the
>> programming sequence to .power_on() stub which is invoked after
>> .init(). PEX/SATA UPHY is initialzied in .init().
>>
>> Signed-off-by: JC Kuo <jckuo@...dia.com>
>> ---
>> drivers/phy/tegra/xusb-tegra210.c | 495 ++++++++++++++++--------------
>> drivers/phy/tegra/xusb.c | 2 +-
>> drivers/phy/tegra/xusb.h | 6 +-
>> 3 files changed, 270 insertions(+), 233 deletions(-)
>
> You've listed 4 logically separate changes in the commit message, so I'm
> wondering if it's possible to split this patch into 4 different ones. It
> might not be worth doing that if they all basically fix the sequence in
> one go, but it's pretty difficult to review this as-is.
I found #1 and #3 are not possible to be split. I will submit #2 and #4 as
separate changes.
>
>>
>> diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c
>> index 66bd4613835b..3a2d9797fb9f 100644
>> --- a/drivers/phy/tegra/xusb-tegra210.c
>> +++ b/drivers/phy/tegra/xusb-tegra210.c
>> @@ -256,23 +256,52 @@ to_tegra210_xusb_padctl(struct tegra_xusb_padctl *padctl)
>> return container_of(padctl, struct tegra210_xusb_padctl, base);
>> }
>>
>> +static const struct tegra_xusb_lane_map tegra210_usb3_map[] = {
>> + { 0, "pcie", 6 },
>> + { 1, "pcie", 5 },
>> + { 2, "pcie", 0 },
>> + { 2, "pcie", 3 },
>> + { 3, "pcie", 4 },
>> + { 3, "pcie", 4 },
>> + { 0, NULL, 0 }
>> +};
>> +
>> +static int tegra210_usb3_lane_map(struct tegra_xusb_lane *lane)
>> +{
>> + const struct tegra_xusb_lane_map *map;
>> +
>> + for (map = tegra210_usb3_map; map->type; map++) {
>> + if (map->index == lane->index &&
>> + strcmp(map->type, lane->pad->soc->name) == 0) {
>> + dev_dbg(lane->pad->padctl->dev,
>> + "lane = %s map to port = usb3-%d\n",
>
> "mapped to port"?
Yes, each PEX/SATA lane maps to an USB3 (super-speed) port.
>
>> + lane->pad->soc->lanes[lane->index].name,
>> + map->port);
>> + return map->port;
>> + }
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> /* must be called under padctl->lock */
>> static int tegra210_pex_uphy_enable(struct tegra_xusb_padctl *padctl)
>> {
>> struct tegra_xusb_pcie_pad *pcie = to_pcie_pad(padctl->pcie);
>> unsigned long timeout;
>> u32 value;
>> - int err;
>> + int err, i;
>
> i should be unsigned to match the type of padctl->pcie->soc->num_lanes.
I will fix this. Thanks.
>
>>
>> - if (pcie->enable > 0) {
>> - pcie->enable++;
>> + if (pcie->enable)
>> return 0;
>> - }
>>
>> err = clk_prepare_enable(pcie->pll);
>> if (err < 0)
>> return err;
>>
>> + if (tegra210_plle_hw_sequence_is_enabled())
>> + goto skip_pll_init;
>> +
>> err = reset_control_deassert(pcie->rst);
>
> Is it guaranteed that the reset is asserted if the PLLE HW sequencer is
> enabled? I suppose with the change to not enable the sequencer by
> default in one of the earlier patches this may indeed be a valid
> assumption.
Yes, reset is de-asserted before PLLE initialization happens.
>
>> if (err < 0)
>> goto disable;
>> @@ -455,7 +484,14 @@ static int tegra210_pex_uphy_enable(struct tegra_xusb_padctl *padctl)
>>
>> tegra210_xusb_pll_hw_sequence_start();
>>
>> - pcie->enable++;
>> +skip_pll_init:
>> + pcie->enable = true;
>> +
>> + for (i = 0; i < padctl->pcie->soc->num_lanes; i++) {
>> + value = padctl_readl(padctl, XUSB_PADCTL_USB3_PAD_MUX);
>> + value |= XUSB_PADCTL_USB3_PAD_MUX_PCIE_IDDQ_DISABLE(i);
>> + padctl_writel(padctl, value, XUSB_PADCTL_USB3_PAD_MUX);
>> + }
>>
>> return 0;
>>
>> @@ -469,34 +505,42 @@ static int tegra210_pex_uphy_enable(struct tegra_xusb_padctl *padctl)
>> static void tegra210_pex_uphy_disable(struct tegra_xusb_padctl *padctl)
>> {
>> struct tegra_xusb_pcie_pad *pcie = to_pcie_pad(padctl->pcie);
>> + u32 value;
>> + int i;
>
> Same as above.
I will fix this. Thanks.
>
>>
>> - mutex_lock(&padctl->lock);
>> -
>> - if (WARN_ON(pcie->enable == 0))
>> - goto unlock;
>> + if (WARN_ON(!pcie->enable))
>> + return;
>>
>> - if (--pcie->enable > 0)
>> - goto unlock;
>> + pcie->enable = false;
>>
>> - reset_control_assert(pcie->rst);
>> + for (i = 0; i < padctl->pcie->soc->num_lanes; i++) {
>> + value = padctl_readl(padctl, XUSB_PADCTL_USB3_PAD_MUX);
>> + value &= ~XUSB_PADCTL_USB3_PAD_MUX_PCIE_IDDQ_DISABLE(i);
>> + padctl_writel(padctl, value, XUSB_PADCTL_USB3_PAD_MUX);
>> + }
>> clk_disable_unprepare(pcie->pll);
>
> Please leave a blank line after a block for better readability.
I will fix this. Thanks.
>
>> -
>> -unlock:
>> - mutex_unlock(&padctl->lock);
>> }
>>
>> /* must be called under padctl->lock */
>> -static int tegra210_sata_uphy_enable(struct tegra_xusb_padctl *padctl, bool usb)
>> +static int tegra210_sata_uphy_enable(struct tegra_xusb_padctl *padctl)
>> {
>> struct tegra_xusb_sata_pad *sata = to_sata_pad(padctl->sata);
>> + struct tegra_xusb_lane *lane = tegra_xusb_find_lane(padctl, "sata", 0);
>> unsigned long timeout;
>> u32 value;
>> - int err;
>> + int err, i;
>
> Same comment as above for "i".
I will fix this. Thanks.
>
>> + bool usb;
>>
>> - if (sata->enable > 0) {
>> - sata->enable++;
>> + if (sata->enable)
>
> Do we want a WARN_ON() here for symmetry with the implementation of
> tegra210_sata_uphy_disable() below?
Yes, I can add this.
>
>> return 0;
>> - }
>> +
>> + if (!lane)
>> + return 0;
>> +
>> + if (tegra210_plle_hw_sequence_is_enabled())
>> + goto skip_pll_init;
>> +
>> + usb = tegra_xusb_lane_check(lane, "usb3-ss");
>>
>> err = clk_prepare_enable(sata->pll);
>> if (err < 0)
>> @@ -697,7 +741,14 @@ static int tegra210_sata_uphy_enable(struct tegra_xusb_padctl *padctl, bool usb)
>>
>> tegra210_sata_pll_hw_sequence_start();
>>
>> - sata->enable++;
>> +skip_pll_init:
>> + sata->enable = true;
>> +
>> + for (i = 0; i < padctl->sata->soc->num_lanes; i++) {
>> + value = padctl_readl(padctl, XUSB_PADCTL_USB3_PAD_MUX);
>> + value |= XUSB_PADCTL_USB3_PAD_MUX_SATA_IDDQ_DISABLE(i);
>> + padctl_writel(padctl, value, XUSB_PADCTL_USB3_PAD_MUX);
>> + }
>>
>> return 0;
>>
>> @@ -711,31 +762,26 @@ static int tegra210_sata_uphy_enable(struct tegra_xusb_padctl *padctl, bool usb)
>> static void tegra210_sata_uphy_disable(struct tegra_xusb_padctl *padctl)
>> {
>> struct tegra_xusb_sata_pad *sata = to_sata_pad(padctl->sata);
>> + u32 value;
>> + int i;
>
> unsigned int, please.
I will fix this. Thanks.
>
>>
>> - mutex_lock(&padctl->lock);
>> -
>> - if (WARN_ON(sata->enable == 0))
>> - goto unlock;
>> + if (WARN_ON(!sata->enable))
>> + return;
>>
>> - if (--sata->enable > 0)
>> - goto unlock;
>> + sata->enable = false;
>>
>> - reset_control_assert(sata->rst);
>> + for (i = 0; i < padctl->sata->soc->num_lanes; i++) {
>> + value = padctl_readl(padctl, XUSB_PADCTL_USB3_PAD_MUX);
>> + value &= ~XUSB_PADCTL_USB3_PAD_MUX_SATA_IDDQ_DISABLE(i);
>> + padctl_writel(padctl, value, XUSB_PADCTL_USB3_PAD_MUX);
>> + }
>> clk_disable_unprepare(sata->pll);
>> -
>> -unlock:
>> - mutex_unlock(&padctl->lock);
>> }
>>
>> -static int tegra210_xusb_padctl_enable(struct tegra_xusb_padctl *padctl)
>> +static void tegra210_aux_mux_lp0_clamp_disable(struct tegra_xusb_padctl *padctl)
>> {
>> u32 value;
>>
>> - mutex_lock(&padctl->lock);
>> -
>> - if (padctl->enable++ > 0)
>> - goto out;
>> -
>> value = padctl_readl(padctl, XUSB_PADCTL_ELPG_PROGRAM1);
>> value &= ~XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN;
>> padctl_writel(padctl, value, XUSB_PADCTL_ELPG_PROGRAM1);
>> @@ -751,24 +797,12 @@ static int tegra210_xusb_padctl_enable(struct tegra_xusb_padctl *padctl)
>> value = padctl_readl(padctl, XUSB_PADCTL_ELPG_PROGRAM1);
>> value &= ~XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_VCORE_DOWN;
>> padctl_writel(padctl, value, XUSB_PADCTL_ELPG_PROGRAM1);
>> -
>> -out:
>> - mutex_unlock(&padctl->lock);
>> - return 0;
>> }
>>
>> -static int tegra210_xusb_padctl_disable(struct tegra_xusb_padctl *padctl)
>> +static void tegra210_aux_mux_lp0_clamp_enable(struct tegra_xusb_padctl *padctl)
>> {
>> u32 value;
>>
>> - mutex_lock(&padctl->lock);
>> -
>> - if (WARN_ON(padctl->enable == 0))
>> - goto out;
>> -
>> - if (--padctl->enable > 0)
>> - goto out;
>> -
>> value = padctl_readl(padctl, XUSB_PADCTL_ELPG_PROGRAM1);
>> value |= XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_VCORE_DOWN;
>> padctl_writel(padctl, value, XUSB_PADCTL_ELPG_PROGRAM1);
>> @@ -784,12 +818,36 @@ static int tegra210_xusb_padctl_disable(struct tegra_xusb_padctl *padctl)
>> value = padctl_readl(padctl, XUSB_PADCTL_ELPG_PROGRAM1);
>> value |= XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN;
>> padctl_writel(padctl, value, XUSB_PADCTL_ELPG_PROGRAM1);
>> +}
>> +
>> +static int tegra210_uphy_init(struct tegra_xusb_padctl *padctl)
>> +{
>> + if (padctl->pcie)
>> + tegra210_pex_uphy_enable(padctl);
>> + if (padctl->sata)
>> + tegra210_sata_uphy_enable(padctl);
>> +
>> + if (!tegra210_plle_hw_sequence_is_enabled())
>> + tegra210_plle_hw_sequence_start();
>> + else
>> + dev_dbg(padctl->dev, "PLLE is already in HW control\n");
>> +
>> + tegra210_aux_mux_lp0_clamp_disable(padctl);
>>
>> -out:
>> - mutex_unlock(&padctl->lock);
>> return 0;
>> }
>>
>> +static void __maybe_unused
>> +tegra210_uphy_deinit(struct tegra_xusb_padctl *padctl)
>> +{
>> + tegra210_aux_mux_lp0_clamp_enable(padctl);
>
> Do we need tegra210_plle_hw_sequence_stop() here?
>
PLLE hardware power sequencer must remain enabled at SC7 entry.
>> +
>> + if (padctl->pcie)
>> + tegra210_pex_uphy_disable(padctl);
>> + if (padctl->sata)
>> + tegra210_sata_uphy_disable(padctl);
>
> Maybe reverse the order of these two so that they are symmetrical with
> tegra210_uphy_init()? Also, single blank lines between the two blocks
> make this easier to read, in my opinion.
I can do this. Thanks.
>
> Thierry
>
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