Re: [PATCH v2 14/21] ipmi: kcs_bmc: Allow clients to control KCS IRQ state

Zev Weiss
2021-04-09T04:38:19Z

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").

>+
>+ 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...

>+}
>+
> static irqreturn_t npcm7xx_kcs_irq(int irq, void *arg)
> {
> struct kcs_bmc_device *kcs_bmc = arg;
>@@ -151,6 +162,7 @@ static int npcm7xx_kcs_config_irq(struct kcs_bmc_device *kcs_bmc,
> }
>
> static const struct kcs_bmc_device_ops npcm7xx_kcs_ops = {
>+ .irq_mask_update = npcm7xx_kcs_irq_mask_update,
> .io_inputb = npcm7xx_kcs_inb,
> .io_outputb = npcm7xx_kcs_outb,
> .io_updateb = npcm7xx_kcs_updateb,
>@@ -191,11 +203,13 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, priv);
>
>- npcm7xx_kcs_enable_channel(kcs_bmc, true);
> rc = npcm7xx_kcs_config_irq(kcs_bmc, pdev);
> if (rc)
> return rc;
>
>+ npcm7xx_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE),
>+ KCS_BMC_EVENT_TYPE_IBF);
>+ npcm7xx_kcs_enable_channel(kcs_bmc, true);
>
> pr_info("channel=%u idr=0x%x odr=0x%x str=0x%x\n",
> chan,
>@@ -211,6 +225,9 @@ static int npcm7xx_kcs_remove(struct platform_device *pdev)
>
> kcs_bmc_remove_device(kcs_bmc);
>
>+ npcm7xx_kcs_enable_channel(kcs_bmc, false);
>+ npcm7xx_kcs_irq_mask_update(kcs_bmc, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE), 0);
>+
> return 0;
> }
>
>--
>2.27.0
>