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References: <20210319062752.145730-1-andrew@aj.id.au>
 <20210319062752.145730-14-andrew@aj.id.au> <YG/Z/eZCES65fXQi@packtop>
Date:   Fri, 09 Apr 2021 16:09:09 +0930
From:   "Andrew Jeffery" <andrew@aj.id.au>
To:     "Zev Weiss" <zweiss@equinix.com>
Cc:     "openipmi-developer@lists.sourceforge.net" 
        <openipmi-developer@lists.sourceforge.net>,
        "openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>,
        "Corey Minyard" <minyard@acm.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "Ryan Chen" <ryan_chen@aspeedtech.com>,
        "Tomer Maimon" <tmaimon77@gmail.com>,
        "linux-aspeed@lists.ozlabs.org" <linux-aspeed@lists.ozlabs.org>,
        "Avi Fishman" <avifishman70@gmail.com>,
        "Patrick Venture" <venture@google.com>,
        "Linus Walleij" <linus.walleij@linaro.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Tali Perry" <tali.perry1@gmail.com>,
        "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
        "Rob Herring" <robh+dt@kernel.org>,
        "Lee Jones" <lee.jones@linaro.org>,
        "Chia-Wei, Wang" <chiawei_wang@aspeedtech.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "Benjamin Fair" <benjaminfair@google.com>
Subject: =?UTF-8?Q?Re:_[PATCH_v2_14/21]_ipmi:_kcs=5Fbmc:_Allow_clients_to_control?=
 =?UTF-8?Q?_KCS_IRQ_state?=
Content-Type: text/plain
Precedence: bulk


On Fri, 9 Apr 2021, at 14:07, Zev Weiss wrote:
> On Fri, Mar 19, 2021 at 01:27:45AM CDT, Andrew Jeffery wrote:
> >Add a mechanism for controlling whether the client associated with a
> >KCS device will receive Input Buffer Full (IBF) and Output Buffer Empty
> >(OBE) events. This enables an abstract implementation of poll() for KCS
> >devices.
> >
> >A wart in the implementation is that the ASPEED KCS devices don't
> >support an OBE interrupt for the BMC. Instead we pretend it has one by
> >polling the status register waiting for the Output Buffer Full (OBF) bit
> >to clear, and generating an event when OBE is observed.
> >
> >Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> >---
> > drivers/char/ipmi/kcs_bmc.c         |   6 ++
> > drivers/char/ipmi/kcs_bmc.h         |   3 +
> > drivers/char/ipmi/kcs_bmc_aspeed.c  | 150 ++++++++++++++++++----------
> > drivers/char/ipmi/kcs_bmc_client.h  |   2 +
> > drivers/char/ipmi/kcs_bmc_device.h  |   1 +
> > drivers/char/ipmi/kcs_bmc_npcm7xx.c |  25 ++++-
> > 6 files changed, 130 insertions(+), 57 deletions(-)
> >
> >diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
> >index 694db6ee2a92..05bbb72418b2 100644
> >--- a/drivers/char/ipmi/kcs_bmc.c
> >+++ b/drivers/char/ipmi/kcs_bmc.c
> >@@ -184,6 +184,12 @@ int kcs_bmc_unregister_cdev(struct kcs_bmc_cdev *cdev)
> > }
> > EXPORT_SYMBOL(kcs_bmc_unregister_cdev);
> >
> >+void kcs_bmc_update_event_mask(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 events)
> >+{
> >+	kcs_bmc->ops->irq_mask_update(kcs_bmc, mask, events);
> >+}
> >+EXPORT_SYMBOL(kcs_bmc_update_event_mask);
> >+
> > MODULE_LICENSE("GPL v2");
> > MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");
> > MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
> >diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
> >index 5deb9a0b8e60..11fff935218c 100644
> >--- a/drivers/char/ipmi/kcs_bmc.h
> >+++ b/drivers/char/ipmi/kcs_bmc.h
> >@@ -11,6 +11,9 @@
> > #define KCS_BMC_EVENT_NONE	0
> > #define KCS_BMC_EVENT_HANDLED	1
> >
> >+#define KCS_BMC_EVENT_TYPE_OBE	BIT(0)
> >+#define KCS_BMC_EVENT_TYPE_IBF	BIT(1)
> >+
> > #define KCS_BMC_STR_OBF		BIT(0)
> > #define KCS_BMC_STR_IBF		BIT(1)
> > #define KCS_BMC_STR_CMD_DAT	BIT(3)
> >diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c
> >index 6f26e7366c0b..5f26471c038c 100644
> >--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
> >+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
> >@@ -60,10 +60,18 @@
> > #define LPC_ODR4             0x118
> > #define LPC_STR4             0x11C
> >
> >+#define OBE_POLL_PERIOD	     (HZ / 2)
> >+
> > struct aspeed_kcs_bmc {
> > 	struct kcs_bmc_device kcs_bmc;
> >
> > 	struct regmap *map;
> >+
> >+	struct {
> >+		spinlock_t lock;
> >+		bool remove;
> >+		struct timer_list timer;
> >+	} obe;
> > };
> >
> > struct aspeed_kcs_of_ops {
> >@@ -159,68 +167,89 @@ static void aspeed_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enabl
> >
> > 	switch (kcs_bmc->channel) {
> > 	case 1:
> >-		if (enable) {
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF1, LPC_HICR2_IBFIF1);
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC1E, LPC_HICR0_LPC1E);
> >-		} else {
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC1E, 0);
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF1, 0);
> >-		}
> >-		break;
> >-
> >+		regmap_update_bits(priv->map, LPC_HICR0, LPC_HICR0_LPC1E, enable * LPC_HICR0_LPC1E);
> >+		return;
> > 	case 2:
> >-		if (enable) {
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF2, LPC_HICR2_IBFIF2);
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC2E, LPC_HICR0_LPC2E);
> >-		} else {
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC2E, 0);
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF2, 0);
> >-		}
> >-		break;
> >-
> >+		regmap_update_bits(priv->map, LPC_HICR0, LPC_HICR0_LPC2E, enable * LPC_HICR0_LPC2E);
> >+		return;
> > 	case 3:
> >-		if (enable) {
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF3, LPC_HICR2_IBFIF3);
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC3E, LPC_HICR0_LPC3E);
> >-			regmap_update_bits(priv->map, LPC_HICR4,
> >-					LPC_HICR4_KCSENBL, LPC_HICR4_KCSENBL);
> >-		} else {
> >-			regmap_update_bits(priv->map, LPC_HICR0,
> >-					LPC_HICR0_LPC3E, 0);
> >-			regmap_update_bits(priv->map, LPC_HICR4,
> >-					LPC_HICR4_KCSENBL, 0);
> >-			regmap_update_bits(priv->map, LPC_HICR2,
> >-					LPC_HICR2_IBFIF3, 0);
> >-		}
> >-		break;
> >-
> >+		regmap_update_bits(priv->map, LPC_HICR0, LPC_HICR0_LPC3E, enable * LPC_HICR0_LPC3E);
> >+		regmap_update_bits(priv->map, LPC_HICR4,
> >+				   LPC_HICR4_KCSENBL, enable * LPC_HICR4_KCSENBL);
> >+		return;
> > 	case 4:
> >-		if (enable)
> >-			regmap_update_bits(priv->map, LPC_HICRB,
> >-					LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
> >-					LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E);
> >+		regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_LPC4E, enable * LPC_HICRB_LPC4E);
> >+		return;
> >+	default:
> >+		pr_warn("%s: Unsupported channel: %d", __func__, kcs_bmc->channel);
> >+		return;
> >+	}
> >+}
> >+
> >+static void aspeed_kcs_check_obe(struct timer_list *timer)
> >+{
> >+	struct aspeed_kcs_bmc *priv = container_of(timer, struct aspeed_kcs_bmc, obe.timer);
> >+	unsigned long flags;
> >+	u8 str;
> >+
> >+	spin_lock_irqsave(&priv->obe.lock, flags);
> >+	if (priv->obe.remove) {
> >+		spin_unlock_irqrestore(&priv->obe.lock, flags);
> >+		return;
> >+	}
> >+
> >+	str = aspeed_kcs_inb(&priv->kcs_bmc, priv->kcs_bmc.ioreg.str);
> >+	if (str & KCS_BMC_STR_OBF) {
> >+		mod_timer(timer, jiffies + OBE_POLL_PERIOD);
> >+		spin_unlock_irqrestore(&priv->obe.lock, flags);
> >+		return;
> >+	}
> >+	spin_unlock_irqrestore(&priv->obe.lock, flags);
> >+
> >+	kcs_bmc_handle_event(&priv->kcs_bmc);
> >+}
> >+
> >+static void aspeed_kcs_irq_mask_update(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 state)
> >+{
> >+	struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
> >+
> >+	/* We don't have an OBE IRQ, emulate it */
> >+	if (KCS_BMC_EVENT_TYPE_OBE & mask) {
> >+		if (KCS_BMC_EVENT_TYPE_OBE & state)
> >+			mod_timer(&priv->obe.timer, jiffies + OBE_POLL_PERIOD);
> > 		else
> >-			regmap_update_bits(priv->map, LPC_HICRB,
> >-					LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
> >-					0);
> >-		break;
> >+			del_timer(&priv->obe.timer);
> >+	}
> >
> >-	default:
> >-		break;
> >+	if (KCS_BMC_EVENT_TYPE_IBF & mask) {
> >+		const bool enable = !!(KCS_BMC_EVENT_TYPE_IBF & state);
> 
> Totally superficial nitpick: the operand ordering for the bitmask tests
> in this function seem a bit inconsistent with what I think is the usual
> style of 'variable & BITMASK_MACRO' (reminiscent of "yoda
> conditionals").

Haha, I'm not sure what possessed me here.

> 
> >+
> >+		switch (kcs_bmc->channel) {
> >+		case 1:
> >+			regmap_update_bits(priv->map, LPC_HICR2, LPC_HICR2_IBFIF1,
> >+					   enable * LPC_HICR2_IBFIF1);
> >+			return;
> >+		case 2:
> >+			regmap_update_bits(priv->map, LPC_HICR2, LPC_HICR2_IBFIF2,
> >+					   enable * LPC_HICR2_IBFIF2);
> >+			return;
> >+		case 3:
> >+			regmap_update_bits(priv->map, LPC_HICR2, LPC_HICR2_IBFIF3,
> >+					   enable * LPC_HICR2_IBFIF3);
> >+			return;
> >+		case 4:
> >+			regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_IBFIF4,
> >+					   enable * LPC_HICRB_IBFIF4);
> >+			return;
> >+		default:
> >+			pr_warn("%s: Unsupported channel: %d", __func__, kcs_bmc->channel);
> >+			return;
> >+		}
> > 	}
> > }
> >
> > static const struct kcs_bmc_device_ops aspeed_kcs_ops = {
> >+	.irq_mask_update = aspeed_kcs_irq_mask_update,
> > 	.io_inputb = aspeed_kcs_inb,
> > 	.io_outputb = aspeed_kcs_outb,
> > 	.io_updateb = aspeed_kcs_updateb,
> >@@ -378,6 +407,10 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> > 		return -ENODEV;
> > 	}
> >
> >+	spin_lock_init(&priv->obe.lock);
> >+	priv->obe.remove = false;
> >+	timer_setup(&priv->obe.timer, aspeed_kcs_check_obe, 0);
> >+
> > 	aspeed_kcs_set_address(kcs_bmc, addr);
> >
> > 	rc = aspeed_kcs_config_irq(kcs_bmc, pdev);
> >@@ -386,6 +419,8 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
> >
> > 	platform_set_drvdata(pdev, priv);
> >
> >+	aspeed_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE),
> >+				   KCS_BMC_EVENT_TYPE_IBF);
> > 	aspeed_kcs_enable_channel(kcs_bmc, true);
> >
> > 	rc = kcs_bmc_add_device(&priv->kcs_bmc);
> >@@ -404,6 +439,15 @@ static int aspeed_kcs_remove(struct platform_device *pdev)
> >
> > 	kcs_bmc_remove_device(kcs_bmc);
> >
> >+	aspeed_kcs_enable_channel(kcs_bmc, false);
> >+	aspeed_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE), 0);
> >+
> >+	/* Make sure it's proper dead */
> >+	spin_lock_irq(&priv->obe.lock);
> >+	priv->obe.remove = true;
> >+	spin_unlock_irq(&priv->obe.lock);
> >+	del_timer_sync(&priv->obe.timer);
> >+
> > 	return 0;
> > }
> >
> >diff --git a/drivers/char/ipmi/kcs_bmc_client.h b/drivers/char/ipmi/kcs_bmc_client.h
> >index d0a7404ff584..456796da33de 100644
> >--- a/drivers/char/ipmi/kcs_bmc_client.h
> >+++ b/drivers/char/ipmi/kcs_bmc_client.h
> >@@ -37,6 +37,8 @@ int kcs_bmc_unregister_cdev(struct kcs_bmc_cdev *cdev);
> > int kcs_bmc_enable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client);
> > void kcs_bmc_disable_device(struct kcs_bmc_device *kcs_bmc, struct kcs_bmc_client *client);
> >
> >+void kcs_bmc_update_event_mask(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 events);
> >+
> > u8 kcs_bmc_read_data(struct kcs_bmc_device *kcs_bmc);
> > void kcs_bmc_write_data(struct kcs_bmc_device *kcs_bmc, u8 data);
> > u8 kcs_bmc_read_status(struct kcs_bmc_device *kcs_bmc);
> >diff --git a/drivers/char/ipmi/kcs_bmc_device.h b/drivers/char/ipmi/kcs_bmc_device.h
> >index 57b7174b2bac..f1ca8912496a 100644
> >--- a/drivers/char/ipmi/kcs_bmc_device.h
> >+++ b/drivers/char/ipmi/kcs_bmc_device.h
> >@@ -7,6 +7,7 @@
> > #include "kcs_bmc.h"
> >
> > struct kcs_bmc_device_ops {
> >+	void (*irq_mask_update)(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 enable);
> > 	u8 (*io_inputb)(struct kcs_bmc_device *kcs_bmc, u32 reg);
> > 	void (*io_outputb)(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 b);
> > 	void (*io_updateb)(struct kcs_bmc_device *kcs_bmc, u32 reg, u8 mask, u8 b);
> >diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >index dce93ec895fc..c2032728a03d 100644
> >--- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >+++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
> >@@ -38,6 +38,7 @@
> > #define KCS2CTL		0x2A
> > #define KCS3CTL		0x3C
> > #define    KCS_CTL_IBFIE	BIT(0)
> >+#define    KCS_CTL_OBEIE	BIT(0)
> >
> > #define KCS1IE		0x1C
> > #define KCS2IE		0x2E
> >@@ -117,13 +118,23 @@ static void npcm7xx_kcs_enable_channel(struct kcs_bmc_device *kcs_bmc, bool enab
> > {
> > 	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> >
> >-	regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
> >-			   enable ? KCS_CTL_IBFIE : 0);
> >-
> > 	regmap_update_bits(priv->map, priv->reg->ie, KCS_IE_IRQE | KCS_IE_HIRQE,
> > 			   enable ? KCS_IE_IRQE | KCS_IE_HIRQE : 0);
> > }
> >
> >+static void npcm7xx_kcs_irq_mask_update(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 state)
> >+{
> >+	struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
> >+
> >+	if (KCS_BMC_EVENT_TYPE_OBE & mask)
> >+		regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_OBEIE,
> >+				   !!(KCS_BMC_EVENT_TYPE_OBE & state) * KCS_CTL_OBEIE);
> >+
> >+	if (KCS_BMC_EVENT_TYPE_IBF & mask)
> >+		regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
> >+				   !!(KCS_BMC_EVENT_TYPE_IBF & state) * KCS_CTL_IBFIE);
> 
> Same operand ordering thing here...

Ack.

Andrew