Re: [PATCH v2 03/12] phy: tegra: xusb: t210: rearrange UPHY init

From: Thierry Reding <hidden>
Date: 2020-08-31 11:42:20
Also in: linux-devicetree, linux-tegra, lkml

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

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@nvidia.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.

quoted hunk ↗ jump to hunk

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"?

+				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.

 
-	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.

quoted hunk ↗ jump to hunk

 	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.

 
-	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.

-
-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".

+	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?

quoted hunk ↗ jump to hunk

 		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.

quoted hunk ↗ jump to hunk

 
-	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?

+
+	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.

Thierry

Attachments

signature.asc [application/pgp-signature] 833 bytes

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help