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[RFC,5/5] ipmi:bt-bmc: Add Microwatt

Message ID 20211006021205.2579057-5-anton@ozlabs.org (mailing list archive)
State Handled Elsewhere, archived
Headers show
Series [RFC,1/5] ipmi:bt-bmc: Separate out ASPEED specific bits | expand

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Commit Message

Anton Blanchard Oct. 6, 2021, 2:12 a.m. UTC
This adds the Microwatt specific bits, including interrupt support.

Signed-off-by: Anton Blanchard <anton@ozlabs.org>
---
 .../devicetree/bindings/ipmi/ibt-bmc.txt      |  1 +
 drivers/char/ipmi/Kconfig                     |  8 ++-
 drivers/char/ipmi/bt-bmc.c                    | 69 +++++++++++++++++++
 3 files changed, 75 insertions(+), 3 deletions(-)

Comments

Joel Stanley Oct. 6, 2021, 2:35 a.m. UTC | #1
Hi Anton,

On Wed, 6 Oct 2021 at 02:12, Anton Blanchard <anton@ozlabs.org> wrote:
>
> This adds the Microwatt specific bits, including interrupt support.

The series looks good.

I've got a couple of patches on the ipmi list that this will conflict with:

 https://sourceforge.net/p/openipmi/mailman/message/37345391/
 https://lore.kernel.org/all/20210903015314.177987-1-joel@jms.id.au/

If there's no feedback from others I suggest basing your series on top
of those, and sending them to Corey on the ipmi list to merge.

Cheers,

Joel

>
> Signed-off-by: Anton Blanchard <anton@ozlabs.org>
> ---
>  .../devicetree/bindings/ipmi/ibt-bmc.txt      |  1 +
>  drivers/char/ipmi/Kconfig                     |  8 ++-
>  drivers/char/ipmi/bt-bmc.c                    | 69 +++++++++++++++++++
>  3 files changed, 75 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> index 78ee716a950e..1b661daf0193 100644
> --- a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> +++ b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> @@ -9,6 +9,7 @@ Required properties:
>  - compatible : should be one of
>         "aspeed,ast2400-ibt-bmc"
>         "aspeed,ast2500-ibt-bmc"
> +       "ibm,microwatt-ibt-bmc"
>  - reg: physical address and size of the registers
>
>  Optional properties:
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index 8b2f0f675e5f..079302f4eef2 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -152,13 +152,15 @@ config IPMI_KCS_BMC_SERIO
>           called kcs_bmc_serio.
>
>  config BT_IPMI_BMC
> -       depends on ARCH_ASPEED || COMPILE_TEST
> +       depends on ARCH_ASPEED || PPC_MICROWATT || COMPILE_TEST
>         depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
>         tristate "BT IPMI bmc driver"
>         help
>           Provides a driver for the BT (Block Transfer) IPMI interface
> -         found on Aspeed SOCs (AST2400 and AST2500). The driver
> -         implements the BMC side of the BT interface.
> +         found on Aspeed SOCs (AST2400 and AST2500) as well as the OpenPOWER
> +         LPC peripheral macro at
> +         <https://github.com/OpenPOWERFoundation/lpcperipheral>
> +         The driver implements the BMC side of the BT interface.
>
>  config IPMB_DEVICE_INTERFACE
>         tristate 'IPMB Interface handler'
> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> index b48e04405ac4..24327b57c60b 100644
> --- a/drivers/char/ipmi/bt-bmc.c
> +++ b/drivers/char/ipmi/bt-bmc.c
> @@ -41,6 +41,11 @@
>  #define   BT_CR2_IRQ_HBUSY     0x40
>  #define ASPEED_BT_CR3  0xc
>
> +#define MICROWATT_IRQ_MASK     0x0
> +#define MICROWATT_IRQ_STATUS   0x4
> +#define   IRQ_HOST_TO_BMC_ATTN 0x1
> +#define   IRQ_HOST_NOT_BUSY    0x2
> +
>  #define BT_CTRL                0x10
>  #define   BT_CTRL_B_BUSY               0x80
>  #define   BT_CTRL_H_BUSY               0x40
> @@ -395,6 +400,27 @@ static irqreturn_t aspeed_bt_bmc_irq(int irq, void *arg)
>         return IRQ_HANDLED;
>  }
>
> +static irqreturn_t microwatt_bt_bmc_irq(int irq, void *arg)
> +{
> +       struct bt_bmc *bt_bmc = arg;
> +       u32 reg;
> +       int rc;
> +
> +       rc = regmap_read(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, &reg);
> +       if (rc)
> +               return IRQ_NONE;
> +
> +       /* Interrupt wasn't something we knew about */
> +       if (!(reg & (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY)))
> +               return IRQ_NONE;
> +
> +       /* ack all pending IRQs */
> +       regmap_write(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, 0);
> +
> +       wake_up(&bt_bmc->queue);
> +       return IRQ_HANDLED;
> +}
> +
>  static int aspeed_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
>                              struct platform_device *pdev)
>  {
> @@ -446,6 +472,48 @@ static const struct bt_bmc_ops aspeed_bt_bmc_ops = {
>         .enable_bt = aspeed_enable_bt,
>  };
>
> +static int microwatt_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> +                            struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       int rc;
> +
> +       bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> +       if (bt_bmc->irq < 0)
> +               return bt_bmc->irq;
> +
> +       rc = devm_request_irq(dev, bt_bmc->irq, microwatt_bt_bmc_irq, IRQF_SHARED,
> +                             DEVICE_NAME, bt_bmc);
> +       if (rc < 0) {
> +               dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
> +               bt_bmc->irq = rc;
> +               return rc;
> +       }
> +
> +       /*
> +        * Configure the hardware to give us an interrupt whenever the H2B
> +        * bit is set or the HBUSY bit is cleared.
> +        *
> +        * H2B will be asserted when the bmc has data for us; HBUSY
> +        * will be cleared (along with B2H) when we can write the next
> +        * message to the BT buffer
> +        */
> +       rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_MASK,
> +                               (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY),
> +                               (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY));
> +
> +       return rc;
> +}
> +
> +static void microwatt_enable_bt(struct bt_bmc *bt_bmc)
> +{
> +}
> +
> +static const struct bt_bmc_ops microwatt_bt_bmc_ops = {
> +       .config_irq = microwatt_bt_bmc_config_irq,
> +       .enable_bt = microwatt_enable_bt,
> +};
> +
>  static int bt_bmc_probe(struct platform_device *pdev)
>  {
>         struct bt_bmc *bt_bmc;
> @@ -530,6 +598,7 @@ static int bt_bmc_remove(struct platform_device *pdev)
>  static const struct of_device_id bt_bmc_match[] = {
>         { .compatible = "aspeed,ast2400-ibt-bmc", .data = &aspeed_bt_bmc_ops },
>         { .compatible = "aspeed,ast2500-ibt-bmc", .data = &aspeed_bt_bmc_ops },
> +       { .compatible = "ibm,microwatt-ibt-bmc", .data = &microwatt_bt_bmc_ops },
>         { },
>  };
>
> --
> 2.31.1
>
Anton Blanchard Oct. 6, 2021, 3:06 a.m. UTC | #2
Hi Joel,

> The series looks good.
> 
> I've got a couple of patches on the ipmi list that this will conflict
> with:
> 
>  https://sourceforge.net/p/openipmi/mailman/message/37345391/
>  https://lore.kernel.org/all/20210903015314.177987-1-joel@jms.id.au/
> 
> If there's no feedback from others I suggest basing your series on top
> of those, and sending them to Corey on the ipmi list to merge.

Looks good, will do.

Thanks,
Anton

> Cheers,
> 
> Joel
> 
> >
> > Signed-off-by: Anton Blanchard <anton@ozlabs.org>
> > ---
> >  .../devicetree/bindings/ipmi/ibt-bmc.txt      |  1 +
> >  drivers/char/ipmi/Kconfig                     |  8 ++-
> >  drivers/char/ipmi/bt-bmc.c                    | 69
> > +++++++++++++++++++ 3 files changed, 75 insertions(+), 3
> > deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> > b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt index
> > 78ee716a950e..1b661daf0193 100644 ---
> > a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt +++
> > b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt @@ -9,6 +9,7
> > @@ Required properties:
> >  - compatible : should be one of
> >         "aspeed,ast2400-ibt-bmc"
> >         "aspeed,ast2500-ibt-bmc"
> > +       "ibm,microwatt-ibt-bmc"
> >  - reg: physical address and size of the registers
> >
> >  Optional properties:
> > diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> > index 8b2f0f675e5f..079302f4eef2 100644
> > --- a/drivers/char/ipmi/Kconfig
> > +++ b/drivers/char/ipmi/Kconfig
> > @@ -152,13 +152,15 @@ config IPMI_KCS_BMC_SERIO
> >           called kcs_bmc_serio.
> >
> >  config BT_IPMI_BMC
> > -       depends on ARCH_ASPEED || COMPILE_TEST
> > +       depends on ARCH_ASPEED || PPC_MICROWATT || COMPILE_TEST
> >         depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
> >         tristate "BT IPMI bmc driver"
> >         help
> >           Provides a driver for the BT (Block Transfer) IPMI
> > interface
> > -         found on Aspeed SOCs (AST2400 and AST2500). The driver
> > -         implements the BMC side of the BT interface.
> > +         found on Aspeed SOCs (AST2400 and AST2500) as well as the
> > OpenPOWER
> > +         LPC peripheral macro at
> > +         <https://github.com/OpenPOWERFoundation/lpcperipheral>
> > +         The driver implements the BMC side of the BT interface.
> >
> >  config IPMB_DEVICE_INTERFACE
> >         tristate 'IPMB Interface handler'
> > diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> > index b48e04405ac4..24327b57c60b 100644
> > --- a/drivers/char/ipmi/bt-bmc.c
> > +++ b/drivers/char/ipmi/bt-bmc.c
> > @@ -41,6 +41,11 @@
> >  #define   BT_CR2_IRQ_HBUSY     0x40
> >  #define ASPEED_BT_CR3  0xc
> >
> > +#define MICROWATT_IRQ_MASK     0x0
> > +#define MICROWATT_IRQ_STATUS   0x4
> > +#define   IRQ_HOST_TO_BMC_ATTN 0x1
> > +#define   IRQ_HOST_NOT_BUSY    0x2
> > +
> >  #define BT_CTRL                0x10
> >  #define   BT_CTRL_B_BUSY               0x80
> >  #define   BT_CTRL_H_BUSY               0x40
> > @@ -395,6 +400,27 @@ static irqreturn_t aspeed_bt_bmc_irq(int irq,
> > void *arg) return IRQ_HANDLED;
> >  }
> >
> > +static irqreturn_t microwatt_bt_bmc_irq(int irq, void *arg)
> > +{
> > +       struct bt_bmc *bt_bmc = arg;
> > +       u32 reg;
> > +       int rc;
> > +
> > +       rc = regmap_read(bt_bmc->map, bt_bmc->offset +
> > MICROWATT_IRQ_STATUS, &reg);
> > +       if (rc)
> > +               return IRQ_NONE;
> > +
> > +       /* Interrupt wasn't something we knew about */
> > +       if (!(reg & (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY)))
> > +               return IRQ_NONE;
> > +
> > +       /* ack all pending IRQs */
> > +       regmap_write(bt_bmc->map, bt_bmc->offset +
> > MICROWATT_IRQ_STATUS, 0); +
> > +       wake_up(&bt_bmc->queue);
> > +       return IRQ_HANDLED;
> > +}
> > +
> >  static int aspeed_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> >                              struct platform_device *pdev)
> >  {
> > @@ -446,6 +472,48 @@ static const struct bt_bmc_ops
> > aspeed_bt_bmc_ops = { .enable_bt = aspeed_enable_bt,
> >  };
> >
> > +static int microwatt_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> > +                            struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       int rc;
> > +
> > +       bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> > +       if (bt_bmc->irq < 0)
> > +               return bt_bmc->irq;
> > +
> > +       rc = devm_request_irq(dev, bt_bmc->irq,
> > microwatt_bt_bmc_irq, IRQF_SHARED,
> > +                             DEVICE_NAME, bt_bmc);
> > +       if (rc < 0) {
> > +               dev_warn(dev, "Unable to request IRQ %d\n",
> > bt_bmc->irq);
> > +               bt_bmc->irq = rc;
> > +               return rc;
> > +       }
> > +
> > +       /*
> > +        * Configure the hardware to give us an interrupt whenever
> > the H2B
> > +        * bit is set or the HBUSY bit is cleared.
> > +        *
> > +        * H2B will be asserted when the bmc has data for us; HBUSY
> > +        * will be cleared (along with B2H) when we can write the
> > next
> > +        * message to the BT buffer
> > +        */
> > +       rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset +
> > MICROWATT_IRQ_MASK,
> > +                               (IRQ_HOST_TO_BMC_ATTN |
> > IRQ_HOST_NOT_BUSY),
> > +                               (IRQ_HOST_TO_BMC_ATTN |
> > IRQ_HOST_NOT_BUSY)); +
> > +       return rc;
> > +}
> > +
> > +static void microwatt_enable_bt(struct bt_bmc *bt_bmc)
> > +{
> > +}
> > +
> > +static const struct bt_bmc_ops microwatt_bt_bmc_ops = {
> > +       .config_irq = microwatt_bt_bmc_config_irq,
> > +       .enable_bt = microwatt_enable_bt,
> > +};
> > +
> >  static int bt_bmc_probe(struct platform_device *pdev)
> >  {
> >         struct bt_bmc *bt_bmc;
> > @@ -530,6 +598,7 @@ static int bt_bmc_remove(struct platform_device
> > *pdev) static const struct of_device_id bt_bmc_match[] = {
> >         { .compatible = "aspeed,ast2400-ibt-bmc", .data =
> > &aspeed_bt_bmc_ops }, { .compatible = "aspeed,ast2500-ibt-bmc",
> > .data = &aspeed_bt_bmc_ops },
> > +       { .compatible = "ibm,microwatt-ibt-bmc", .data =
> > &microwatt_bt_bmc_ops }, { },
> >  };
> >
> > --
> > 2.31.1
> >  
>
Cédric Le Goater Oct. 6, 2021, 6 a.m. UTC | #3
On 10/6/21 04:12, Anton Blanchard wrote:
> This adds the Microwatt specific bits, including interrupt support.
> 
> Signed-off-by: Anton Blanchard <anton@ozlabs.org>
> ---
>   .../devicetree/bindings/ipmi/ibt-bmc.txt      |  1 +
>   drivers/char/ipmi/Kconfig                     |  8 ++-
>   drivers/char/ipmi/bt-bmc.c                    | 69 +++++++++++++++++++
>   3 files changed, 75 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> index 78ee716a950e..1b661daf0193 100644
> --- a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> +++ b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
> @@ -9,6 +9,7 @@ Required properties:
>   - compatible : should be one of
>   	"aspeed,ast2400-ibt-bmc"
>   	"aspeed,ast2500-ibt-bmc"
> +	"ibm,microwatt-ibt-bmc"
>   - reg: physical address and size of the registers
>   
>   Optional properties:
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index 8b2f0f675e5f..079302f4eef2 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -152,13 +152,15 @@ config IPMI_KCS_BMC_SERIO
>   	  called kcs_bmc_serio.
>   
>   config BT_IPMI_BMC
> -	depends on ARCH_ASPEED || COMPILE_TEST
> +	depends on ARCH_ASPEED || PPC_MICROWATT || COMPILE_TEST
>   	depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
>   	tristate "BT IPMI bmc driver"
>   	help
>   	  Provides a driver for the BT (Block Transfer) IPMI interface
> -	  found on Aspeed SOCs (AST2400 and AST2500). The driver
> -	  implements the BMC side of the BT interface.
> +	  found on Aspeed SOCs (AST2400 and AST2500) as well as the OpenPOWER
> +	  LPC peripheral macro at
> +	  <https://github.com/OpenPOWERFoundation/lpcperipheral>
> +	  The driver implements the BMC side of the BT interface.
>   
>   config IPMB_DEVICE_INTERFACE
>   	tristate 'IPMB Interface handler'
> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> index b48e04405ac4..24327b57c60b 100644
> --- a/drivers/char/ipmi/bt-bmc.c
> +++ b/drivers/char/ipmi/bt-bmc.c
> @@ -41,6 +41,11 @@
>   #define   BT_CR2_IRQ_HBUSY	0x40
>   #define ASPEED_BT_CR3	0xc
>   
> +#define MICROWATT_IRQ_MASK	0x0
> +#define MICROWATT_IRQ_STATUS	0x4
> +#define   IRQ_HOST_TO_BMC_ATTN	0x1
> +#define   IRQ_HOST_NOT_BUSY	0x2
> +
>   #define BT_CTRL		0x10
>   #define   BT_CTRL_B_BUSY		0x80
>   #define   BT_CTRL_H_BUSY		0x40
> @@ -395,6 +400,27 @@ static irqreturn_t aspeed_bt_bmc_irq(int irq, void *arg)
>   	return IRQ_HANDLED;
>   }
>   
> +static irqreturn_t microwatt_bt_bmc_irq(int irq, void *arg)
> +{
> +	struct bt_bmc *bt_bmc = arg;
> +	u32 reg;
> +	int rc;
> +
> +	rc = regmap_read(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, &reg);
> +	if (rc)
> +		return IRQ_NONE;
> +
> +	/* Interrupt wasn't something we knew about */
> +	if (!(reg & (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY)))
> +		return IRQ_NONE;
> +
> +	/* ack all pending IRQs */
> +	regmap_write(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, 0);
> +
> +	wake_up(&bt_bmc->queue);
> +	return IRQ_HANDLED;
> +}
> +
>   static int aspeed_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
>   			     struct platform_device *pdev)
>   {
> @@ -446,6 +472,48 @@ static const struct bt_bmc_ops aspeed_bt_bmc_ops = {
>   	.enable_bt = aspeed_enable_bt,
>   };
>   
> +static int microwatt_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> +			     struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int rc;
> +
> +	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
> +	if (bt_bmc->irq < 0)
> +		return bt_bmc->irq;
> +
> +	rc = devm_request_irq(dev, bt_bmc->irq, microwatt_bt_bmc_irq, IRQF_SHARED,
> +			      DEVICE_NAME, bt_bmc);
> +	if (rc < 0) {
> +		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
> +		bt_bmc->irq = rc;
> +		return rc;
> +	}
> +
> +	/*
> +	 * Configure the hardware to give us an interrupt whenever the H2B
> +	 * bit is set or the HBUSY bit is cleared.
> +	 *
> +	 * H2B will be asserted when the bmc has data for us; HBUSY
> +	 * will be cleared (along with B2H) when we can write the next
> +	 * message to the BT buffer
> +	 */
> +	rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_MASK,
> +				(IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY),
> +				(IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY));

This is the only difference. May be we could introduce a ->config_irq_hw()
handler to keep a larger part common. No big deal.

Reviewed-by: Cédric Le Goater <clg@kaod.org>

C.


> +	return rc;
> +}
> +
> +static void microwatt_enable_bt(struct bt_bmc *bt_bmc)
> +{
> +}
> +
> +static const struct bt_bmc_ops microwatt_bt_bmc_ops = {
> +	.config_irq = microwatt_bt_bmc_config_irq,
> +	.enable_bt = microwatt_enable_bt,
> +};
> +
>   static int bt_bmc_probe(struct platform_device *pdev)
>   {
>   	struct bt_bmc *bt_bmc;
> @@ -530,6 +598,7 @@ static int bt_bmc_remove(struct platform_device *pdev)
>   static const struct of_device_id bt_bmc_match[] = {
>   	{ .compatible = "aspeed,ast2400-ibt-bmc", .data = &aspeed_bt_bmc_ops },
>   	{ .compatible = "aspeed,ast2500-ibt-bmc", .data = &aspeed_bt_bmc_ops },
> +	{ .compatible = "ibm,microwatt-ibt-bmc", .data = &microwatt_bt_bmc_ops },
>   	{ },
>   };
>   
>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
index 78ee716a950e..1b661daf0193 100644
--- a/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
+++ b/Documentation/devicetree/bindings/ipmi/ibt-bmc.txt
@@ -9,6 +9,7 @@  Required properties:
 - compatible : should be one of
 	"aspeed,ast2400-ibt-bmc"
 	"aspeed,ast2500-ibt-bmc"
+	"ibm,microwatt-ibt-bmc"
 - reg: physical address and size of the registers
 
 Optional properties:
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
index 8b2f0f675e5f..079302f4eef2 100644
--- a/drivers/char/ipmi/Kconfig
+++ b/drivers/char/ipmi/Kconfig
@@ -152,13 +152,15 @@  config IPMI_KCS_BMC_SERIO
 	  called kcs_bmc_serio.
 
 config BT_IPMI_BMC
-	depends on ARCH_ASPEED || COMPILE_TEST
+	depends on ARCH_ASPEED || PPC_MICROWATT || COMPILE_TEST
 	depends on REGMAP && REGMAP_MMIO && MFD_SYSCON
 	tristate "BT IPMI bmc driver"
 	help
 	  Provides a driver for the BT (Block Transfer) IPMI interface
-	  found on Aspeed SOCs (AST2400 and AST2500). The driver
-	  implements the BMC side of the BT interface.
+	  found on Aspeed SOCs (AST2400 and AST2500) as well as the OpenPOWER
+	  LPC peripheral macro at
+	  <https://github.com/OpenPOWERFoundation/lpcperipheral>
+	  The driver implements the BMC side of the BT interface.
 
 config IPMB_DEVICE_INTERFACE
 	tristate 'IPMB Interface handler'
diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
index b48e04405ac4..24327b57c60b 100644
--- a/drivers/char/ipmi/bt-bmc.c
+++ b/drivers/char/ipmi/bt-bmc.c
@@ -41,6 +41,11 @@ 
 #define   BT_CR2_IRQ_HBUSY	0x40
 #define ASPEED_BT_CR3	0xc
 
+#define MICROWATT_IRQ_MASK	0x0
+#define MICROWATT_IRQ_STATUS	0x4
+#define   IRQ_HOST_TO_BMC_ATTN	0x1
+#define   IRQ_HOST_NOT_BUSY	0x2
+
 #define BT_CTRL		0x10
 #define   BT_CTRL_B_BUSY		0x80
 #define   BT_CTRL_H_BUSY		0x40
@@ -395,6 +400,27 @@  static irqreturn_t aspeed_bt_bmc_irq(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t microwatt_bt_bmc_irq(int irq, void *arg)
+{
+	struct bt_bmc *bt_bmc = arg;
+	u32 reg;
+	int rc;
+
+	rc = regmap_read(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, &reg);
+	if (rc)
+		return IRQ_NONE;
+
+	/* Interrupt wasn't something we knew about */
+	if (!(reg & (IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY)))
+		return IRQ_NONE;
+
+	/* ack all pending IRQs */
+	regmap_write(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_STATUS, 0);
+
+	wake_up(&bt_bmc->queue);
+	return IRQ_HANDLED;
+}
+
 static int aspeed_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
 			     struct platform_device *pdev)
 {
@@ -446,6 +472,48 @@  static const struct bt_bmc_ops aspeed_bt_bmc_ops = {
 	.enable_bt = aspeed_enable_bt,
 };
 
+static int microwatt_bt_bmc_config_irq(struct bt_bmc *bt_bmc,
+			     struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int rc;
+
+	bt_bmc->irq = platform_get_irq_optional(pdev, 0);
+	if (bt_bmc->irq < 0)
+		return bt_bmc->irq;
+
+	rc = devm_request_irq(dev, bt_bmc->irq, microwatt_bt_bmc_irq, IRQF_SHARED,
+			      DEVICE_NAME, bt_bmc);
+	if (rc < 0) {
+		dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
+		bt_bmc->irq = rc;
+		return rc;
+	}
+
+	/*
+	 * Configure the hardware to give us an interrupt whenever the H2B
+	 * bit is set or the HBUSY bit is cleared.
+	 *
+	 * H2B will be asserted when the bmc has data for us; HBUSY
+	 * will be cleared (along with B2H) when we can write the next
+	 * message to the BT buffer
+	 */
+	rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + MICROWATT_IRQ_MASK,
+				(IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY),
+				(IRQ_HOST_TO_BMC_ATTN | IRQ_HOST_NOT_BUSY));
+
+	return rc;
+}
+
+static void microwatt_enable_bt(struct bt_bmc *bt_bmc)
+{
+}
+
+static const struct bt_bmc_ops microwatt_bt_bmc_ops = {
+	.config_irq = microwatt_bt_bmc_config_irq,
+	.enable_bt = microwatt_enable_bt,
+};
+
 static int bt_bmc_probe(struct platform_device *pdev)
 {
 	struct bt_bmc *bt_bmc;
@@ -530,6 +598,7 @@  static int bt_bmc_remove(struct platform_device *pdev)
 static const struct of_device_id bt_bmc_match[] = {
 	{ .compatible = "aspeed,ast2400-ibt-bmc", .data = &aspeed_bt_bmc_ops },
 	{ .compatible = "aspeed,ast2500-ibt-bmc", .data = &aspeed_bt_bmc_ops },
+	{ .compatible = "ibm,microwatt-ibt-bmc", .data = &microwatt_bt_bmc_ops },
 	{ },
 };