[PATCH v3 0/3] soc: add NPCM BPC driver support

[PATCH v3 0/3] soc: add NPCM BPC driver support

[Tomer Maimon]

This patch set adds BIOS Post code (BPC) support for the Nuvoton 
NPCM Baseboard Management Controller (BMC).

Nuvoton BMC NPCM BIOS Post Code (BPC) monitoring two configurable 
I/O addresses written by the host on the bus, the capture data 
stored in 128-word FIFO.

NPCM BPC can support capture double words.

The NPCM BPC driver tested on NPCM750 Olympus board.

Addressed comments from:
 - Krzysztof Kozlowski : https://www.spinics.net/lists/kernel/msg5035188.html
 - Conor Dooley : https://www.spinics.net/lists/kernel/msg5034239.html
 - kernel test robot : https://www.spinics.net/lists/kernel/msg5034970.html

Changes since version 2:
 - Modify compatible bindings.
 - Add more details to nuvoton,bpc-en-dwcapture parameter. 
 - Using _is_visible() function to support NPCM8XX.
 - add __poll_t custom.

Changes since version 1:
 - Remove LPC present from the BPC driver.
 - Modify dt-bindings message header.
 - Add vendor to the file name.
 - Modify incorrect spelling.
 
Tomer Maimon (3):
  dt-bindings: soc: nuvoton: Add NPCM BPC
  soc: nuvoton: add configuration menu
  soc: nuvoton: add NPCM BPC driver

 .../soc/nuvoton/nuvoton,npcm-bpc.yaml         |  65 +++
 drivers/soc/nuvoton/Kconfig                   |  16 +-
 drivers/soc/nuvoton/Makefile                  |   1 +
 drivers/soc/nuvoton/npcm-bpc.c                | 387 ++++++++++++++++++
 4 files changed, 468 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
 create mode 100644 drivers/soc/nuvoton/npcm-bpc.c

-- 
2.34.1

[PATCH v3 1/3] dt-bindings: soc: nuvoton: Add NPCM BPC

[Tomer Maimon]

Added device tree binding documentation for Nuvoton BMC NPCM BIOS Post
Code (BPC).

The NPCM BPC monitoring two configurable I/O addresses written by the
host on the bus.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
 .../soc/nuvoton/nuvoton,npcm-bpc.yaml         | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml

diff --git a/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
new file mode 100644
index 000000000000..c04302a1d52b
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/nuvoton/nuvoton,npcm-bpc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton BMC NPCM BIOS Post Code (BPC) controller
+
+maintainers:
+  - Tomer Maimon <tmaimon77@gmail.com>
+
+description:
+  Nuvoton BMC NPCM BIOS Post Code (BPC) monitoring two configurable I/O
+  addresses written by the host on the bus, the capture data stored in
+  128-word FIFO.
+
+  NPCM BPC supports capture double words, when using capture
+  double word only I/O address 1 is monitored.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - nuvoton,npcm845-bpc
+          - nuvoton,npcm750-bpc
+      - const: nuvoton,npcm-bpc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  nuvoton,monitor-ports:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+      Contain monitor I/O addresses on the bus, at least one monitor I/O
+      address required.
+
+  nuvoton,bpc-en-dwcapture:
+    description:
+      Set DWCAPTURE bit in BPCFEN register that enable double words capture
+      according to the first address setting.
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - nuvoton,monitor-ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    bpc: bpc@f0007040 {
+        compatible = "nuvoton,npcm750-bpc", "nuvoton,npcm-bpc";
+        reg = <0xf0007040 0x20>;
+        interrupts = <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>;
+        nuvoton,monitor-ports = <0x80>;
+    };
+...
-- 
2.34.1

[PATCH v3 2/3] soc: nuvoton: add configuration menu

[Tomer Maimon]

Add menu configuration to Nuvoton SoC drivers.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
 drivers/soc/nuvoton/Kconfig | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
index df46182088ec..d5102f5f0c28 100644
--- a/drivers/soc/nuvoton/Kconfig
+++ b/drivers/soc/nuvoton/Kconfig
@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
-menuconfig WPCM450_SOC
+
+menu "NUVOTON SoC drivers"
+
+config WPCM450_SOC
 	tristate "Nuvoton WPCM450 SoC driver"
 	default y if ARCH_WPCM450
 	select SOC_BUS
@@ -9,3 +12,5 @@ menuconfig WPCM450_SOC
 
 	  This driver provides information such as the SoC model and
 	  revision.
+
+endmenu
-- 
2.34.1

[PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Tomer Maimon]

Add Nuvoton BMC NPCM BIOS post code (BPC) driver.

The NPCM BPC monitoring two configurable I/O address written by the host
on the bus.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
 drivers/soc/nuvoton/Kconfig    |   9 +
 drivers/soc/nuvoton/Makefile   |   1 +
 drivers/soc/nuvoton/npcm-bpc.c | 387 +++++++++++++++++++++++++++++++++
 3 files changed, 397 insertions(+)
 create mode 100644 drivers/soc/nuvoton/npcm-bpc.c

diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
index d5102f5f0c28..ebd162633942 100644
--- a/drivers/soc/nuvoton/Kconfig
+++ b/drivers/soc/nuvoton/Kconfig
@@ -2,6 +2,15 @@
 
 menu "NUVOTON SoC drivers"
 
+config NPCM_BPC
+	tristate "NPCM BIOS Post Code support"
+	depends on (ARCH_NPCM || COMPILE_TEST)
+	help
+	  Provides NPCM driver to control the BIOS Post Code
+	  interface which allows the BMC to monitor and save
+	  the data written by the host to an arbitrary I/O port,
+	  the BPC is connected to the host thourgh LPC or eSPI bus.
+
 config WPCM450_SOC
 	tristate "Nuvoton WPCM450 SoC driver"
 	default y if ARCH_WPCM450
diff --git a/drivers/soc/nuvoton/Makefile b/drivers/soc/nuvoton/Makefile
index e30317b4e829..c6c96079c6e9 100644
--- a/drivers/soc/nuvoton/Makefile
+++ b/drivers/soc/nuvoton/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_NPCM_BPC)		+= npcm-bpc.o
 obj-$(CONFIG_WPCM450_SOC)	+= wpcm450-soc.o
diff --git a/drivers/soc/nuvoton/npcm-bpc.c b/drivers/soc/nuvoton/npcm-bpc.c
new file mode 100644
index 000000000000..cb5e5a11d6d8
--- /dev/null
+++ b/drivers/soc/nuvoton/npcm-bpc.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Nuvoton Technology corporation.
+
+#include <linux/fs.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/kfifo.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+
+#define DEVICE_NAME	"npcm-bpc"
+
+#define NUM_BPC_CHANNELS	2
+#define DW_PAD_SIZE		3
+
+/* BIOS POST Code FIFO Registers */
+#define NPCM_BPCFA2L_REG	0x2 //BIOS POST Code FIFO Address 2 LSB
+#define NPCM_BPCFA2M_REG	0x4 //BIOS POST Code FIFO Address 2 MSB
+#define NPCM_BPCFEN_REG		0x6 //BIOS POST Code FIFO Enable
+#define NPCM_BPCFSTAT_REG	0x8 //BIOS POST Code FIFO Status
+#define NPCM_BPCFDATA_REG	0xA //BIOS POST Code FIFO Data
+#define NPCM_BPCFMSTAT_REG	0xC //BIOS POST Code FIFO Miscellaneous Status
+#define NPCM_BPCFA1L_REG	0x10 //BIOS POST Code FIFO Address 1 LSB
+#define NPCM_BPCFA1M_REG	0x12 //BIOS POST Code FIFO Address 1 MSB
+
+/* BIOS register data */
+#define FIFO_IOADDR1_ENABLE	0x80
+#define FIFO_IOADDR2_ENABLE	0x40
+
+/* BPC interface package and structure definition */
+#define BPC_KFIFO_SIZE		0x400
+
+/* BPC register data */
+#define FIFO_DATA_VALID		0x80
+#define FIFO_OVERFLOW		0x20
+#define FIFO_READY_INT_ENABLE	0x8
+#define FIFO_DWCAPTURE		0x4
+#define FIFO_ADDR_DECODE	0x1
+
+/* Host Reset */
+#define HOST_RESET_INT_ENABLE	0x10
+#define HOST_RESET_CHANGED	0x40
+
+struct npcm_bpc_channel {
+	struct npcm_bpc	*data;
+	struct kfifo		fifo;
+	wait_queue_head_t	wq;
+	bool			host_reset;
+	struct miscdevice	miscdev;
+};
+
+struct npcm_bpc {
+	void __iomem		*base;
+	struct device		*dev;
+	int			irq;
+	bool			en_dwcap;
+	struct npcm_bpc_channel	ch[NUM_BPC_CHANNELS];
+};
+
+static struct npcm_bpc_channel *npcm_file_to_ch(struct file *file)
+{
+	return container_of(file->private_data, struct npcm_bpc_channel,
+			    miscdev);
+}
+
+static ssize_t npcm_bpc_read(struct file *file, char __user *buffer,
+			     size_t count, loff_t *ppos)
+{
+	struct npcm_bpc_channel *chan = npcm_file_to_ch(file);
+	struct npcm_bpc *bpc = chan->data;
+	unsigned int copied;
+	int cond_size = 1;
+	int ret = 0;
+
+	if (bpc->en_dwcap)
+		cond_size = 3;
+
+	if (kfifo_len(&chan->fifo) < cond_size) {
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		ret = wait_event_interruptible
+			(chan->wq, kfifo_len(&chan->fifo) > cond_size);
+		if (ret == -ERESTARTSYS)
+			return -EINTR;
+	}
+
+	ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
+
+	return ret ? ret : copied;
+}
+
+static __poll_t npcm_bpc_poll(struct file *file, struct poll_table_struct *pt)
+{
+	struct npcm_bpc_channel *chan = npcm_file_to_ch(file);
+	__poll_t mask = 0;
+
+	poll_wait(file, &chan->wq, pt);
+	if (!kfifo_is_empty(&chan->fifo))
+		mask = (__poll_t)POLLIN;
+
+	if (chan->host_reset) {
+		mask |= (__poll_t)POLLHUP;
+		chan->host_reset = false;
+	}
+
+	return mask;
+}
+
+static const struct file_operations npcm_bpc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= npcm_bpc_read,
+	.poll		= npcm_bpc_poll,
+	.llseek		= noop_llseek,
+};
+
+static irqreturn_t npcm_bpc_irq(int irq, void *arg)
+{
+	struct npcm_bpc *bpc = arg;
+	u8 fifo_st, host_st, data;
+	bool isr_flag = false;
+	u8 last_addr_bit = 0;
+	u8 padzero[3] = {0};
+	u8 addr_index = 0;
+
+	fifo_st = ioread8(bpc->base + NPCM_BPCFSTAT_REG);
+	while (FIFO_DATA_VALID & fifo_st) {
+		 /* If dwcapture enabled only channel 0 (FIFO 0) used */
+		if (!bpc->en_dwcap)
+			addr_index = fifo_st & FIFO_ADDR_DECODE;
+		else
+			last_addr_bit = fifo_st & FIFO_ADDR_DECODE;
+
+		/* Read data from FIFO to clear interrupt */
+		data = ioread8(bpc->base + NPCM_BPCFDATA_REG);
+		if (kfifo_is_full(&bpc->ch[addr_index].fifo))
+			kfifo_skip(&bpc->ch[addr_index].fifo);
+		kfifo_put(&bpc->ch[addr_index].fifo, data);
+		if (fifo_st & FIFO_OVERFLOW)
+			dev_warn(bpc->dev, "BIOS Post Codes FIFO Overflow\n");
+
+		fifo_st = ioread8(bpc->base + NPCM_BPCFSTAT_REG);
+		if (bpc->en_dwcap && last_addr_bit) {
+			if ((fifo_st & FIFO_ADDR_DECODE) ||
+			    ((FIFO_DATA_VALID & fifo_st) == 0)) {
+				while (kfifo_avail(&bpc->ch[addr_index].fifo) < DW_PAD_SIZE)
+					kfifo_skip(&bpc->ch[addr_index].fifo);
+				kfifo_in(&bpc->ch[addr_index].fifo,
+					 padzero, DW_PAD_SIZE);
+			}
+		}
+		isr_flag = true;
+	}
+
+	host_st = ioread8(bpc->base + NPCM_BPCFMSTAT_REG);
+	if (host_st & HOST_RESET_CHANGED) {
+		iowrite8(HOST_RESET_CHANGED,
+			 bpc->base + NPCM_BPCFMSTAT_REG);
+		bpc->ch[addr_index].host_reset = true;
+		isr_flag = true;
+	}
+
+	if (isr_flag) {
+		wake_up_interruptible(&bpc->ch[addr_index].wq);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int npcm_bpc_config_irq(struct npcm_bpc *bpc,
+			       struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int rc;
+
+	bpc->irq = platform_get_irq(pdev, 0);
+	if (bpc->irq < 0) {
+		dev_err(dev, "get IRQ failed\n");
+		return bpc->irq;
+	}
+
+	rc = devm_request_irq(dev, bpc->irq,
+			      npcm_bpc_irq, IRQF_SHARED,
+			      DEVICE_NAME, bpc);
+	if (rc < 0) {
+		dev_warn(dev, "Unable to request IRQ %d\n", bpc->irq);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int npcm_enable_bpc(struct npcm_bpc *bpc, struct device *dev,
+			   int channel, u16 host_port)
+{
+	u8 addr_en, reg_en;
+	int err;
+
+	init_waitqueue_head(&bpc->ch[channel].wq);
+
+	err = kfifo_alloc(&bpc->ch[channel].fifo, BPC_KFIFO_SIZE,
+			  GFP_KERNEL);
+	if (err)
+		return err;
+
+	bpc->ch[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
+	bpc->ch[channel].miscdev.name =
+		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	bpc->ch[channel].miscdev.fops = &npcm_bpc_fops;
+	bpc->ch[channel].miscdev.parent = dev;
+	err = misc_register(&bpc->ch[channel].miscdev);
+	if (err)
+		return err;
+
+	bpc->ch[channel].data = bpc;
+	bpc->ch[channel].host_reset = false;
+
+	/* Enable host snoop channel at requested port */
+	switch (channel) {
+	case 0:
+		addr_en = FIFO_IOADDR1_ENABLE;
+		iowrite8((u8)host_port & 0xFF,
+			 bpc->base + NPCM_BPCFA1L_REG);
+		iowrite8((u8)(host_port >> 8),
+			 bpc->base + NPCM_BPCFA1M_REG);
+		break;
+	case 1:
+		addr_en = FIFO_IOADDR2_ENABLE;
+		iowrite8((u8)host_port & 0xFF,
+			 bpc->base + NPCM_BPCFA2L_REG);
+		iowrite8((u8)(host_port >> 8),
+			 bpc->base + NPCM_BPCFA2M_REG);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (bpc->en_dwcap)
+		addr_en = FIFO_DWCAPTURE;
+
+	/*
+	 * Enable FIFO Ready Interrupt, FIFO Capture of I/O addr,
+	 * and Host Reset
+	 */
+	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+	iowrite8(reg_en | addr_en | FIFO_READY_INT_ENABLE |
+		 HOST_RESET_INT_ENABLE, bpc->base + NPCM_BPCFEN_REG);
+
+	return 0;
+}
+
+static void npcm_disable_bpc(struct npcm_bpc *bpc, int channel)
+{
+	u8 reg_en;
+
+	switch (channel) {
+	case 0:
+		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+		if (bpc->en_dwcap)
+			iowrite8(reg_en & ~FIFO_DWCAPTURE,
+				 bpc->base + NPCM_BPCFEN_REG);
+		else
+			iowrite8(reg_en & ~FIFO_IOADDR1_ENABLE,
+				 bpc->base + NPCM_BPCFEN_REG);
+		break;
+	case 1:
+		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+		iowrite8(reg_en & ~FIFO_IOADDR2_ENABLE,
+			 bpc->base + NPCM_BPCFEN_REG);
+		break;
+	default:
+		return;
+	}
+
+	if (!(reg_en & (FIFO_IOADDR1_ENABLE | FIFO_IOADDR2_ENABLE)))
+		iowrite8(reg_en &
+			 ~(FIFO_READY_INT_ENABLE | HOST_RESET_INT_ENABLE),
+			 bpc->base + NPCM_BPCFEN_REG);
+
+	kfifo_free(&bpc->ch[channel].fifo);
+	misc_deregister(&bpc->ch[channel].miscdev);
+}
+
+static int npcm_bpc_probe(struct platform_device *pdev)
+{
+	struct npcm_bpc *bpc;
+	struct device *dev;
+	u32 port;
+	int err;
+
+	dev = &pdev->dev;
+
+	bpc = devm_kzalloc(dev, sizeof(*bpc), GFP_KERNEL);
+	if (!bpc)
+		return -ENOMEM;
+
+	bpc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(bpc->base))
+		return PTR_ERR(bpc->base);
+
+	dev_set_drvdata(&pdev->dev, bpc);
+
+	err = of_property_read_u32_index(dev->of_node, "nuvoton,monitor-ports",
+					 0, &port);
+	if (err) {
+		dev_err(dev, "no monitor ports configured\n");
+		return -ENODEV;
+	}
+
+	bpc->en_dwcap =
+		of_property_read_bool(dev->of_node, "nuvoton,bpc-en-dwcapture");
+
+	bpc->dev = dev;
+
+	err = npcm_bpc_config_irq(bpc, pdev);
+	if (err)
+		return err;
+
+	err = npcm_enable_bpc(bpc, dev, 0, port);
+	if (err) {
+		dev_err(dev, "Enable BIOS post code I/O port 0 failed\n");
+		return err;
+	}
+
+	/*
+	 * Configuration of second BPC channel port is optional
+	 * Double-Word Capture ignoring address 2
+	 */
+	if (!bpc->en_dwcap) {
+		if (of_property_read_u32_index(dev->of_node,
+					       "nuvoton,monitor-ports", 1,
+					       &port) == 0) {
+			err = npcm_enable_bpc(bpc, dev, 1, port);
+			if (err) {
+				dev_err(dev, "Enable BIOS post code I/O port 1 failed, disable I/O port 0\n");
+				npcm_disable_bpc(bpc, 0);
+				return err;
+			}
+		}
+	}
+
+	pr_info("NPCM BIOS Post Code probe\n");
+
+	return err;
+}
+
+static int npcm_bpc_remove(struct platform_device *pdev)
+{
+	struct npcm_bpc *bpc = dev_get_drvdata(&pdev->dev);
+	u8 reg_en;
+
+	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+
+	if (reg_en & FIFO_IOADDR1_ENABLE)
+		npcm_disable_bpc(bpc, 0);
+	if (reg_en & FIFO_IOADDR2_ENABLE)
+		npcm_disable_bpc(bpc, 1);
+
+	return 0;
+}
+
+static const struct of_device_id npcm_bpc_match[] = {
+	{ .compatible = "nuvoton,npcm-bpc" },
+	{ },
+};
+
+static struct platform_driver npcm_bpc_driver = {
+	.driver = {
+		.name		= DEVICE_NAME,
+		.of_match_table = npcm_bpc_match,
+	},
+	.probe = npcm_bpc_probe,
+	.remove = npcm_bpc_remove,
+};
+
+module_platform_driver(npcm_bpc_driver);
+
+MODULE_DEVICE_TABLE(of, npcm_bpc_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_DESCRIPTION("NPCM BIOS post code monitoring device driver");
-- 
2.34.1

Re: [PATCH v3 1/3] dt-bindings: soc: nuvoton: Add NPCM BPC

[Krzysztof Kozlowski]

On 13/12/2023 20:05, Tomer Maimon wrote:
> Added device tree binding documentation for Nuvoton BMC NPCM BIOS Post
> Code (BPC).
> 
> The NPCM BPC monitoring two configurable I/O addresses written by the
> host on the bus.
> 
> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> ---
>  .../soc/nuvoton/nuvoton,npcm-bpc.yaml         | 65 +++++++++++++++++++
>  1 file changed, 65 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> new file mode 100644
> index 000000000000..c04302a1d52b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> @@ -0,0 +1,65 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/soc/nuvoton/nuvoton,npcm-bpc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Nuvoton BMC NPCM BIOS Post Code (BPC) controller
> +
> +maintainers:
> +  - Tomer Maimon <tmaimon77@gmail.com>
> +
> +description:
> +  Nuvoton BMC NPCM BIOS Post Code (BPC) monitoring two configurable I/O
> +  addresses written by the host on the bus, the capture data stored in
> +  128-word FIFO.
> +
> +  NPCM BPC supports capture double words, when using capture
> +  double word only I/O address 1 is monitored.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - nuvoton,npcm845-bpc
> +          - nuvoton,npcm750-bpc
> +      - const: nuvoton,npcm-bpc

That's not what I suggested. I asked to make 845 compatible with 750.
This works, but I want to be sure you really, really understand the
consequences of this.

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  nuvoton,monitor-ports:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array

Missing constraints, like min/maxItems and maybe values.

> +    description:
> +      Contain monitor I/O addresses on the bus, at least one monitor I/O
> +      address required.
> +
> +  nuvoton,bpc-en-dwcapture:

nuvoton,double-word-capture?

> +    description:
> +      Set DWCAPTURE bit in BPCFEN register that enable double words capture
> +      according to the first address setting.
> +    type: boolean
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - nuvoton,monitor-ports

Best regards,
Krzysztof

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Krzysztof Kozlowski]

On 13/12/2023 20:05, Tomer Maimon wrote:
> Add Nuvoton BMC NPCM BIOS post code (BPC) driver.
> 
> The NPCM BPC monitoring two configurable I/O address written by the host
> on the bus.
> 
> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> ---
>  drivers/soc/nuvoton/Kconfig    |   9 +
>  drivers/soc/nuvoton/Makefile   |   1 +
>  drivers/soc/nuvoton/npcm-bpc.c | 387 +++++++++++++++++++++++++++++++++
>  3 files changed, 397 insertions(+)
>  create mode 100644 drivers/soc/nuvoton/npcm-bpc.c
> 
> diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
> index d5102f5f0c28..ebd162633942 100644
> --- a/drivers/soc/nuvoton/Kconfig
> +++ b/drivers/soc/nuvoton/Kconfig
> @@ -2,6 +2,15 @@
>  
>  menu "NUVOTON SoC drivers"

...

> +
> +static int npcm_bpc_config_irq(struct npcm_bpc *bpc,
> +			       struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int rc;
> +
> +	bpc->irq = platform_get_irq(pdev, 0);
> +	if (bpc->irq < 0) {
> +		dev_err(dev, "get IRQ failed\n");
> +		return bpc->irq;

return dev_err_probe

> +	}
> +
> +	rc = devm_request_irq(dev, bpc->irq,
> +			      npcm_bpc_irq, IRQF_SHARED,
> +			      DEVICE_NAME, bpc);
> +	if (rc < 0) {
> +		dev_warn(dev, "Unable to request IRQ %d\n", bpc->irq);

return dev_err_probe

> +		return rc;
> +	}
> +
> +	return 0;
> +}
> +
> +static int npcm_enable_bpc(struct npcm_bpc *bpc, struct device *dev,
> +			   int channel, u16 host_port)
> +{
> +	u8 addr_en, reg_en;
> +	int err;
> +
> +	init_waitqueue_head(&bpc->ch[channel].wq);
> +
> +	err = kfifo_alloc(&bpc->ch[channel].fifo, BPC_KFIFO_SIZE,
> +			  GFP_KERNEL);
> +	if (err)
> +		return err;
> +
> +	bpc->ch[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
> +	bpc->ch[channel].miscdev.name =
> +		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
> +	bpc->ch[channel].miscdev.fops = &npcm_bpc_fops;
> +	bpc->ch[channel].miscdev.parent = dev;
> +	err = misc_register(&bpc->ch[channel].miscdev);
> +	if (err)
> +		return err;
> +
> +	bpc->ch[channel].data = bpc;
> +	bpc->ch[channel].host_reset = false;
> +
> +	/* Enable host snoop channel at requested port */
> +	switch (channel) {
> +	case 0:
> +		addr_en = FIFO_IOADDR1_ENABLE;
> +		iowrite8((u8)host_port & 0xFF,
> +			 bpc->base + NPCM_BPCFA1L_REG);
> +		iowrite8((u8)(host_port >> 8),
> +			 bpc->base + NPCM_BPCFA1M_REG);
> +		break;
> +	case 1:
> +		addr_en = FIFO_IOADDR2_ENABLE;
> +		iowrite8((u8)host_port & 0xFF,
> +			 bpc->base + NPCM_BPCFA2L_REG);
> +		iowrite8((u8)(host_port >> 8),
> +			 bpc->base + NPCM_BPCFA2M_REG);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (bpc->en_dwcap)
> +		addr_en = FIFO_DWCAPTURE;
> +
> +	/*
> +	 * Enable FIFO Ready Interrupt, FIFO Capture of I/O addr,
> +	 * and Host Reset
> +	 */
> +	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
> +	iowrite8(reg_en | addr_en | FIFO_READY_INT_ENABLE |
> +		 HOST_RESET_INT_ENABLE, bpc->base + NPCM_BPCFEN_REG);
> +
> +	return 0;
> +}
> +
> +static void npcm_disable_bpc(struct npcm_bpc *bpc, int channel)
> +{
> +	u8 reg_en;
> +
> +	switch (channel) {
> +	case 0:
> +		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
> +		if (bpc->en_dwcap)
> +			iowrite8(reg_en & ~FIFO_DWCAPTURE,
> +				 bpc->base + NPCM_BPCFEN_REG);
> +		else
> +			iowrite8(reg_en & ~FIFO_IOADDR1_ENABLE,
> +				 bpc->base + NPCM_BPCFEN_REG);
> +		break;
> +	case 1:
> +		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
> +		iowrite8(reg_en & ~FIFO_IOADDR2_ENABLE,
> +			 bpc->base + NPCM_BPCFEN_REG);
> +		break;
> +	default:
> +		return;
> +	}
> +
> +	if (!(reg_en & (FIFO_IOADDR1_ENABLE | FIFO_IOADDR2_ENABLE)))
> +		iowrite8(reg_en &
> +			 ~(FIFO_READY_INT_ENABLE | HOST_RESET_INT_ENABLE),
> +			 bpc->base + NPCM_BPCFEN_REG);
> +
> +	kfifo_free(&bpc->ch[channel].fifo);
> +	misc_deregister(&bpc->ch[channel].miscdev);
> +}
> +
> +static int npcm_bpc_probe(struct platform_device *pdev)
> +{
> +	struct npcm_bpc *bpc;
> +	struct device *dev;
> +	u32 port;
> +	int err;
> +
> +	dev = &pdev->dev;
> +
> +	bpc = devm_kzalloc(dev, sizeof(*bpc), GFP_KERNEL);
> +	if (!bpc)
> +		return -ENOMEM;
> +
> +	bpc->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(bpc->base))
> +		return PTR_ERR(bpc->base);
> +
> +	dev_set_drvdata(&pdev->dev, bpc);

Why do you use pdev again? Look earlier, you have local variable for this.

> +
> +	err = of_property_read_u32_index(dev->of_node, "nuvoton,monitor-ports",
> +					 0, &port);
> +	if (err) {
> +		dev_err(dev, "no monitor ports configured\n");
> +		return -ENODEV;
> +	}
> +
> +	bpc->en_dwcap =
> +		of_property_read_bool(dev->of_node, "nuvoton,bpc-en-dwcapture");
> +
> +	bpc->dev = dev;
> +
> +	err = npcm_bpc_config_irq(bpc, pdev);
> +	if (err)
> +		return err;
> +
> +	err = npcm_enable_bpc(bpc, dev, 0, port);
> +	if (err) {
> +		dev_err(dev, "Enable BIOS post code I/O port 0 failed\n");
> +		return err;
> +	}
> +
> +	/*
> +	 * Configuration of second BPC channel port is optional
> +	 * Double-Word Capture ignoring address 2
> +	 */
> +	if (!bpc->en_dwcap) {
> +		if (of_property_read_u32_index(dev->of_node,
> +					       "nuvoton,monitor-ports", 1,
> +					       &port) == 0) {
> +			err = npcm_enable_bpc(bpc, dev, 1, port);
> +			if (err) {
> +				dev_err(dev, "Enable BIOS post code I/O port 1 failed, disable I/O port 0\n");
> +				npcm_disable_bpc(bpc, 0);
> +				return err;
> +			}
> +		}
> +	}
> +
> +	pr_info("NPCM BIOS Post Code probe\n");

Drop

> +
> +	return err;
> +}
> +
> +static int npcm_bpc_remove(struct platform_device *pdev)
> +{
> +	struct npcm_bpc *bpc = dev_get_drvdata(&pdev->dev);
> +	u8 reg_en;
> +
> +	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
> +
> +	if (reg_en & FIFO_IOADDR1_ENABLE)
> +		npcm_disable_bpc(bpc, 0);
> +	if (reg_en & FIFO_IOADDR2_ENABLE)
> +		npcm_disable_bpc(bpc, 1);
> +

Best regards,
Krzysztof

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Arnd Bergmann]

On Wed, Dec 13, 2023, at 20:05, Tomer Maimon wrote:
> Add Nuvoton BMC NPCM BIOS post code (BPC) driver.
>
> The NPCM BPC monitoring two configurable I/O address written by the host
> on the bus.
>
> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> ---
>  drivers/soc/nuvoton/Kconfig    |   9 +
>  drivers/soc/nuvoton/Makefile   |   1 +
>  drivers/soc/nuvoton/npcm-bpc.c | 387 +++++++++++++++++++++++++++++++++
>  3 files changed, 397 insertions(+)
>  create mode 100644 drivers/soc/nuvoton/npcm-bpc.c

I try hard to avoid having user interfaces in drivers/soc/, that
subsystem should primarily be used for things that don't have an
existing subsystem in the kernel and are used by other in-kernel
drivers but don't export hteir own misc device.

> diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
> index d5102f5f0c28..ebd162633942 100644
> --- a/drivers/soc/nuvoton/Kconfig
> +++ b/drivers/soc/nuvoton/Kconfig
> @@ -2,6 +2,15 @@
> 
>  menu "NUVOTON SoC drivers"
> 
> +config NPCM_BPC
> +	tristate "NPCM BIOS Post Code support"
> +	depends on (ARCH_NPCM || COMPILE_TEST)
> +	help
> +	  Provides NPCM driver to control the BIOS Post Code
> +	  interface which allows the BMC to monitor and save
> +	  the data written by the host to an arbitrary I/O port,
> +	  the BPC is connected to the host thourgh LPC or eSPI bus.
> +

This one in particular looks like this might be implemented
by more than one BMC type, it's a fairly generic functionality.

Have you talked to the other maintainers of SoCs used in
OpenBMC about coming up with a common interface?

> +#define DEVICE_NAME	"npcm-bpc"

[nitpicking] No need for macros like this one, open-coding the
string is usually more readable.

    Arnd

Re: [PATCH v3 1/3] dt-bindings: soc: nuvoton: Add NPCM BPC

[Tomer Maimon]

Hi Krzysztof,

Thanks for your comments.

On Thu, 14 Dec 2023 at 09:56, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 13/12/2023 20:05, Tomer Maimon wrote:
> > Added device tree binding documentation for Nuvoton BMC NPCM BIOS Post
> > Code (BPC).
> >
> > The NPCM BPC monitoring two configurable I/O addresses written by the
> > host on the bus.
> >
> > Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> > ---
> >  .../soc/nuvoton/nuvoton,npcm-bpc.yaml         | 65 +++++++++++++++++++
> >  1 file changed, 65 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> > new file mode 100644
> > index 000000000000..c04302a1d52b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/soc/nuvoton/nuvoton,npcm-bpc.yaml
> > @@ -0,0 +1,65 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/soc/nuvoton/nuvoton,npcm-bpc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Nuvoton BMC NPCM BIOS Post Code (BPC) controller
> > +
> > +maintainers:
> > +  - Tomer Maimon <tmaimon77@gmail.com>
> > +
> > +description:
> > +  Nuvoton BMC NPCM BIOS Post Code (BPC) monitoring two configurable I/O
> > +  addresses written by the host on the bus, the capture data stored in
> > +  128-word FIFO.
> > +
> > +  NPCM BPC supports capture double words, when using capture
> > +  double word only I/O address 1 is monitored.
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - nuvoton,npcm845-bpc
> > +          - nuvoton,npcm750-bpc
> > +      - const: nuvoton,npcm-bpc
>
> That's not what I suggested. I asked to make 845 compatible with 750.
> This works, but I want to be sure you really, really understand the
> consequences of this.
Did you mean to do the compatible as follows?
properties:
  compatible:
    items:
      - enum:
          - nuvoton,npcm845-bpc
      - const: nuvoton,npcm750-bpc

Appreciate it if you could explain what is the difference between the
compatibility suggested in V3?
>
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  nuvoton,monitor-ports:
> > +    $ref: /schemas/types.yaml#/definitions/uint32-array
>
> Missing constraints, like min/maxItems and maybe values.
O.K.
>
> > +    description:
> > +      Contain monitor I/O addresses on the bus, at least one monitor I/O
> > +      address required.
> > +
> > +  nuvoton,bpc-en-dwcapture:
>
> nuvoton,double-word-capture?
Modify in V4
>
> > +    description:
> > +      Set DWCAPTURE bit in BPCFEN register that enables double word capture
> > +      according to the first address setting.
> > +    type: boolean
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - nuvoton,monitor-ports
>
> Best regards,
> Krzysztof
>

Thanks,

Tomer

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Tomer Maimon]

Hi Arnd,

Thanks for your comments.

On Thu, 14 Dec 2023 at 14:44, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Wed, Dec 13, 2023, at 20:05, Tomer Maimon wrote:
> > Add Nuvoton BMC NPCM BIOS post code (BPC) driver.
> >
> > The NPCM BPC monitoring two configurable I/O address written by the host
> > on the bus.
> >
> > Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> > ---
> >  drivers/soc/nuvoton/Kconfig    |   9 +
> >  drivers/soc/nuvoton/Makefile   |   1 +
> >  drivers/soc/nuvoton/npcm-bpc.c | 387 +++++++++++++++++++++++++++++++++
> >  3 files changed, 397 insertions(+)
> >  create mode 100644 drivers/soc/nuvoton/npcm-bpc.c
>
> I try hard to avoid having user interfaces in drivers/soc/, that
> subsystem should primarily be used for things that don't have an
> existing subsystem in the kernel and are used by other in-kernel
> drivers but don't export hteir own misc device.
>
> > diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
> > index d5102f5f0c28..ebd162633942 100644
> > --- a/drivers/soc/nuvoton/Kconfig
> > +++ b/drivers/soc/nuvoton/Kconfig
> > @@ -2,6 +2,15 @@
> >
> >  menu "NUVOTON SoC drivers"
> >
> > +config NPCM_BPC
> > +     tristate "NPCM BIOS Post Code support"
> > +     depends on (ARCH_NPCM || COMPILE_TEST)
> > +     help
> > +       Provides NPCM driver to control the BIOS Post Code
> > +       interface which allows the BMC to monitor and save
> > +       the data written by the host to an arbitrary I/O port,
> > +       the BPC is connected to the host thourgh LPC or eSPI bus.
> > +
>
> This one in particular looks like this might be implemented
> by more than one BMC type, it's a fairly generic functionality.
>
> Have you talked to the other maintainers of SoCs used in
> OpenBMC about coming up with a common interface?
Yes, Both Nuvoton and Aspeed use the same user-facing code to manage
the host snooping.
https://github.com/openbmc/phosphor-host-postd
>
> > +#define DEVICE_NAME  "npcm-bpc"
Will do.
>
> [nitpicking] No need for macros like this one, open-coding the
> string is usually more readable.
>
>     Arnd

Thanks,

Tomer

Re: [PATCH v3 1/3] dt-bindings: soc: nuvoton: Add NPCM BPC

[Krzysztof Kozlowski]

On 14/12/2023 14:34, Tomer Maimon wrote:
>>> +properties:
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - nuvoton,npcm845-bpc
>>> +          - nuvoton,npcm750-bpc
>>> +      - const: nuvoton,npcm-bpc
>>
>> That's not what I suggested. I asked to make 845 compatible with 750.
>> This works, but I want to be sure you really, really understand the
>> consequences of this.
> Did you mean to do the compatible as follows?
> properties:
>   compatible:
>     items:
>       - enum:
>           - nuvoton,npcm845-bpc
>       - const: nuvoton,npcm750-bpc
> 
> Appreciate it if you could explain what is the difference between the
> compatibility suggested in V3?

Your v3 says there is a generic, common to all current and future SoCs,
interface to BPC.


Best regards,
Krzysztof

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Arnd Bergmann]

On Thu, Dec 14, 2023, at 14:09, Tomer Maimon wrote:
> On Thu, 14 Dec 2023 at 14:44, Arnd Bergmann <arnd@arndb.de> wrote:
>> >
>> > +config NPCM_BPC
>> > +     tristate "NPCM BIOS Post Code support"
>> > +     depends on (ARCH_NPCM || COMPILE_TEST)
>> > +     help
>> > +       Provides NPCM driver to control the BIOS Post Code
>> > +       interface which allows the BMC to monitor and save
>> > +       the data written by the host to an arbitrary I/O port,
>> > +       the BPC is connected to the host thourgh LPC or eSPI bus.
>> > +
>>
>> This one in particular looks like this might be implemented
>> by more than one BMC type, it's a fairly generic functionality.
>>
>> Have you talked to the other maintainers of SoCs used in
>> OpenBMC about coming up with a common interface?
> Yes, Both Nuvoton and Aspeed use the same user-facing code to manage
> the host snooping.
> https://github.com/openbmc/phosphor-host-postd

Ok, that's good. I found the driver in drivers/soc/aspeed/aspeed-lpc-snoop.c
now and see that the implementation looks very similar. 

I think we should do two things here:

 - split out the common code into a shared module that exports the
   symbols to be used by either one

 - find a better place for both drivers outside of drivers/soc.
   I would suggest drivers/misc/bmc/ but am open to other suggestions.

      Arnd

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Tomer Maimon]

Hi Arnd,

Thanks for your suggestion.

Appreciate it if Joel, OpenBMC Linux kernel maintainer,  could share
his thoughts about it.


On Thu, 14 Dec 2023 at 17:49, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Thu, Dec 14, 2023, at 14:09, Tomer Maimon wrote:
> > On Thu, 14 Dec 2023 at 14:44, Arnd Bergmann <arnd@arndb.de> wrote:
> >> >
> >> > +config NPCM_BP
> >> > +     tristate "NPCM BIOS Post Code support"
> >> > +     depends on (ARCH_NPCM || COMPILE_TEST)
> >> > +     help
> >> > +       Provides NPCM driver to control the BIOS Post Code
> >> > +       interface which allows the BMC to monitor and save
> >> > +       the data written by the host to an arbitrary I/O port,
> >> > +       the BPC is connected to the host thourgh LPC or eSPI bus.
> >> > +
> >>
> >> This one in particular looks like this might be implemented
> >> by more than one BMC type, it's a fairly generic functionality.
> >>
> >> Have you talked to the other maintainers of SoCs used in
> >> OpenBMC about coming up with a common interface?
> > Yes, Both Nuvoton and Aspeed use the same user-facing code to manage
> > the host snooping.
> > https://github.com/openbmc/phosphor-host-postd
>
> Ok, that's good. I found the driver in drivers/soc/aspeed/aspeed-lpc-snoop.c
> now and see that the implementation looks very similar.
>
> I think we should do two things here:
>
>  - split out the common code into a shared module that exports the
>    symbols to be used by either one
>
>  - find a better place for both drivers outside of drivers/soc.
>    I would suggest drivers/misc/bmc/ but am open to other suggestions.
>
>       Arnd

Best regards,

Tomer

Re: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[kernel test robot]

Hi Tomer,

kernel test robot noticed the following build warnings:

[auto build test WARNING on soc/for-next]
[also build test WARNING on robh/for-next linus/master v6.7-rc5 next-20231214]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Tomer-Maimon/dt-bindings-soc-nuvoton-Add-NPCM-BPC/20231214-030714
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
patch link:    https://lore.kernel.org/r/20231213190528.3751583-4-tmaimon77%40gmail.com
patch subject: [PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver
config: arm64-randconfig-r123-20231215 (https://download.01.org/0day-ci/archive/20231215/202312150632.EzPYbn6l-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20231215/202312150632.EzPYbn6l-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312150632.EzPYbn6l-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/soc/nuvoton/npcm-bpc.c:105:25: sparse: sparse: cast to restricted __poll_t
   drivers/soc/nuvoton/npcm-bpc.c:108:26: sparse: sparse: cast to restricted __poll_t

vim +105 drivers/soc/nuvoton/npcm-bpc.c

    97	
    98	static __poll_t npcm_bpc_poll(struct file *file, struct poll_table_struct *pt)
    99	{
   100		struct npcm_bpc_channel *chan = npcm_file_to_ch(file);
   101		__poll_t mask = 0;
   102	
   103		poll_wait(file, &chan->wq, pt);
   104		if (!kfifo_is_empty(&chan->fifo))
 > 105			mask = (__poll_t)POLLIN;
   106	
   107		if (chan->host_reset) {
   108			mask |= (__poll_t)POLLHUP;
   109			chan->host_reset = false;
   110		}
   111	
   112		return mask;
   113	}
   114	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v3 3/3] soc: nuvoton: add NPCM BPC driver

[Tomer Maimon]

Add Nuvoton BMC NPCM BIOS post code (BPC) driver.

The NPCM BPC monitoring two configurable I/O address written by the host
on the bus.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
 drivers/soc/nuvoton/Kconfig    |   9 +
 drivers/soc/nuvoton/Makefile   |   1 +
 drivers/soc/nuvoton/npcm-bpc.c | 387 +++++++++++++++++++++++++++++++++
 3 files changed, 397 insertions(+)
 create mode 100644 drivers/soc/nuvoton/npcm-bpc.c

diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
index d5102f5f0c28..ebd162633942 100644
--- a/drivers/soc/nuvoton/Kconfig
+++ b/drivers/soc/nuvoton/Kconfig
@@ -2,6 +2,15 @@
 
 menu "NUVOTON SoC drivers"
 
+config NPCM_BPC
+	tristate "NPCM BIOS Post Code support"
+	depends on (ARCH_NPCM || COMPILE_TEST)
+	help
+	  Provides NPCM driver to control the BIOS Post Code
+	  interface which allows the BMC to monitor and save
+	  the data written by the host to an arbitrary I/O port,
+	  the BPC is connected to the host thourgh LPC or eSPI bus.
+
 config WPCM450_SOC
 	tristate "Nuvoton WPCM450 SoC driver"
 	default y if ARCH_WPCM450
diff --git a/drivers/soc/nuvoton/Makefile b/drivers/soc/nuvoton/Makefile
index e30317b4e829..c6c96079c6e9 100644
--- a/drivers/soc/nuvoton/Makefile
+++ b/drivers/soc/nuvoton/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_NPCM_BPC)		+= npcm-bpc.o
 obj-$(CONFIG_WPCM450_SOC)	+= wpcm450-soc.o
diff --git a/drivers/soc/nuvoton/npcm-bpc.c b/drivers/soc/nuvoton/npcm-bpc.c
new file mode 100644
index 000000000000..cb5e5a11d6d8
--- /dev/null
+++ b/drivers/soc/nuvoton/npcm-bpc.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Nuvoton Technology corporation.
+
+#include <linux/fs.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/kfifo.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+
+#define DEVICE_NAME	"npcm-bpc"
+
+#define NUM_BPC_CHANNELS	2
+#define DW_PAD_SIZE		3
+
+/* BIOS POST Code FIFO Registers */
+#define NPCM_BPCFA2L_REG	0x2 //BIOS POST Code FIFO Address 2 LSB
+#define NPCM_BPCFA2M_REG	0x4 //BIOS POST Code FIFO Address 2 MSB
+#define NPCM_BPCFEN_REG		0x6 //BIOS POST Code FIFO Enable
+#define NPCM_BPCFSTAT_REG	0x8 //BIOS POST Code FIFO Status
+#define NPCM_BPCFDATA_REG	0xA //BIOS POST Code FIFO Data
+#define NPCM_BPCFMSTAT_REG	0xC //BIOS POST Code FIFO Miscellaneous Status
+#define NPCM_BPCFA1L_REG	0x10 //BIOS POST Code FIFO Address 1 LSB
+#define NPCM_BPCFA1M_REG	0x12 //BIOS POST Code FIFO Address 1 MSB
+
+/* BIOS register data */
+#define FIFO_IOADDR1_ENABLE	0x80
+#define FIFO_IOADDR2_ENABLE	0x40
+
+/* BPC interface package and structure definition */
+#define BPC_KFIFO_SIZE		0x400
+
+/* BPC register data */
+#define FIFO_DATA_VALID		0x80
+#define FIFO_OVERFLOW		0x20
+#define FIFO_READY_INT_ENABLE	0x8
+#define FIFO_DWCAPTURE		0x4
+#define FIFO_ADDR_DECODE	0x1
+
+/* Host Reset */
+#define HOST_RESET_INT_ENABLE	0x10
+#define HOST_RESET_CHANGED	0x40
+
+struct npcm_bpc_channel {
+	struct npcm_bpc	*data;
+	struct kfifo		fifo;
+	wait_queue_head_t	wq;
+	bool			host_reset;
+	struct miscdevice	miscdev;
+};
+
+struct npcm_bpc {
+	void __iomem		*base;
+	struct device		*dev;
+	int			irq;
+	bool			en_dwcap;
+	struct npcm_bpc_channel	ch[NUM_BPC_CHANNELS];
+};
+
+static struct npcm_bpc_channel *npcm_file_to_ch(struct file *file)
+{
+	return container_of(file->private_data, struct npcm_bpc_channel,
+			    miscdev);
+}
+
+static ssize_t npcm_bpc_read(struct file *file, char __user *buffer,
+			     size_t count, loff_t *ppos)
+{
+	struct npcm_bpc_channel *chan = npcm_file_to_ch(file);
+	struct npcm_bpc *bpc = chan->data;
+	unsigned int copied;
+	int cond_size = 1;
+	int ret = 0;
+
+	if (bpc->en_dwcap)
+		cond_size = 3;
+
+	if (kfifo_len(&chan->fifo) < cond_size) {
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		ret = wait_event_interruptible
+			(chan->wq, kfifo_len(&chan->fifo) > cond_size);
+		if (ret == -ERESTARTSYS)
+			return -EINTR;
+	}
+
+	ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
+
+	return ret ? ret : copied;
+}
+
+static __poll_t npcm_bpc_poll(struct file *file, struct poll_table_struct *pt)
+{
+	struct npcm_bpc_channel *chan = npcm_file_to_ch(file);
+	__poll_t mask = 0;
+
+	poll_wait(file, &chan->wq, pt);
+	if (!kfifo_is_empty(&chan->fifo))
+		mask = (__poll_t)POLLIN;
+
+	if (chan->host_reset) {
+		mask |= (__poll_t)POLLHUP;
+		chan->host_reset = false;
+	}
+
+	return mask;
+}
+
+static const struct file_operations npcm_bpc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= npcm_bpc_read,
+	.poll		= npcm_bpc_poll,
+	.llseek		= noop_llseek,
+};
+
+static irqreturn_t npcm_bpc_irq(int irq, void *arg)
+{
+	struct npcm_bpc *bpc = arg;
+	u8 fifo_st, host_st, data;
+	bool isr_flag = false;
+	u8 last_addr_bit = 0;
+	u8 padzero[3] = {0};
+	u8 addr_index = 0;
+
+	fifo_st = ioread8(bpc->base + NPCM_BPCFSTAT_REG);
+	while (FIFO_DATA_VALID & fifo_st) {
+		 /* If dwcapture enabled only channel 0 (FIFO 0) used */
+		if (!bpc->en_dwcap)
+			addr_index = fifo_st & FIFO_ADDR_DECODE;
+		else
+			last_addr_bit = fifo_st & FIFO_ADDR_DECODE;
+
+		/* Read data from FIFO to clear interrupt */
+		data = ioread8(bpc->base + NPCM_BPCFDATA_REG);
+		if (kfifo_is_full(&bpc->ch[addr_index].fifo))
+			kfifo_skip(&bpc->ch[addr_index].fifo);
+		kfifo_put(&bpc->ch[addr_index].fifo, data);
+		if (fifo_st & FIFO_OVERFLOW)
+			dev_warn(bpc->dev, "BIOS Post Codes FIFO Overflow\n");
+
+		fifo_st = ioread8(bpc->base + NPCM_BPCFSTAT_REG);
+		if (bpc->en_dwcap && last_addr_bit) {
+			if ((fifo_st & FIFO_ADDR_DECODE) ||
+			    ((FIFO_DATA_VALID & fifo_st) == 0)) {
+				while (kfifo_avail(&bpc->ch[addr_index].fifo) < DW_PAD_SIZE)
+					kfifo_skip(&bpc->ch[addr_index].fifo);
+				kfifo_in(&bpc->ch[addr_index].fifo,
+					 padzero, DW_PAD_SIZE);
+			}
+		}
+		isr_flag = true;
+	}
+
+	host_st = ioread8(bpc->base + NPCM_BPCFMSTAT_REG);
+	if (host_st & HOST_RESET_CHANGED) {
+		iowrite8(HOST_RESET_CHANGED,
+			 bpc->base + NPCM_BPCFMSTAT_REG);
+		bpc->ch[addr_index].host_reset = true;
+		isr_flag = true;
+	}
+
+	if (isr_flag) {
+		wake_up_interruptible(&bpc->ch[addr_index].wq);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int npcm_bpc_config_irq(struct npcm_bpc *bpc,
+			       struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int rc;
+
+	bpc->irq = platform_get_irq(pdev, 0);
+	if (bpc->irq < 0) {
+		dev_err(dev, "get IRQ failed\n");
+		return bpc->irq;
+	}
+
+	rc = devm_request_irq(dev, bpc->irq,
+			      npcm_bpc_irq, IRQF_SHARED,
+			      DEVICE_NAME, bpc);
+	if (rc < 0) {
+		dev_warn(dev, "Unable to request IRQ %d\n", bpc->irq);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int npcm_enable_bpc(struct npcm_bpc *bpc, struct device *dev,
+			   int channel, u16 host_port)
+{
+	u8 addr_en, reg_en;
+	int err;
+
+	init_waitqueue_head(&bpc->ch[channel].wq);
+
+	err = kfifo_alloc(&bpc->ch[channel].fifo, BPC_KFIFO_SIZE,
+			  GFP_KERNEL);
+	if (err)
+		return err;
+
+	bpc->ch[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
+	bpc->ch[channel].miscdev.name =
+		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	bpc->ch[channel].miscdev.fops = &npcm_bpc_fops;
+	bpc->ch[channel].miscdev.parent = dev;
+	err = misc_register(&bpc->ch[channel].miscdev);
+	if (err)
+		return err;
+
+	bpc->ch[channel].data = bpc;
+	bpc->ch[channel].host_reset = false;
+
+	/* Enable host snoop channel at requested port */
+	switch (channel) {
+	case 0:
+		addr_en = FIFO_IOADDR1_ENABLE;
+		iowrite8((u8)host_port & 0xFF,
+			 bpc->base + NPCM_BPCFA1L_REG);
+		iowrite8((u8)(host_port >> 8),
+			 bpc->base + NPCM_BPCFA1M_REG);
+		break;
+	case 1:
+		addr_en = FIFO_IOADDR2_ENABLE;
+		iowrite8((u8)host_port & 0xFF,
+			 bpc->base + NPCM_BPCFA2L_REG);
+		iowrite8((u8)(host_port >> 8),
+			 bpc->base + NPCM_BPCFA2M_REG);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (bpc->en_dwcap)
+		addr_en = FIFO_DWCAPTURE;
+
+	/*
+	 * Enable FIFO Ready Interrupt, FIFO Capture of I/O addr,
+	 * and Host Reset
+	 */
+	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+	iowrite8(reg_en | addr_en | FIFO_READY_INT_ENABLE |
+		 HOST_RESET_INT_ENABLE, bpc->base + NPCM_BPCFEN_REG);
+
+	return 0;
+}
+
+static void npcm_disable_bpc(struct npcm_bpc *bpc, int channel)
+{
+	u8 reg_en;
+
+	switch (channel) {
+	case 0:
+		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+		if (bpc->en_dwcap)
+			iowrite8(reg_en & ~FIFO_DWCAPTURE,
+				 bpc->base + NPCM_BPCFEN_REG);
+		else
+			iowrite8(reg_en & ~FIFO_IOADDR1_ENABLE,
+				 bpc->base + NPCM_BPCFEN_REG);
+		break;
+	case 1:
+		reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+		iowrite8(reg_en & ~FIFO_IOADDR2_ENABLE,
+			 bpc->base + NPCM_BPCFEN_REG);
+		break;
+	default:
+		return;
+	}
+
+	if (!(reg_en & (FIFO_IOADDR1_ENABLE | FIFO_IOADDR2_ENABLE)))
+		iowrite8(reg_en &
+			 ~(FIFO_READY_INT_ENABLE | HOST_RESET_INT_ENABLE),
+			 bpc->base + NPCM_BPCFEN_REG);
+
+	kfifo_free(&bpc->ch[channel].fifo);
+	misc_deregister(&bpc->ch[channel].miscdev);
+}
+
+static int npcm_bpc_probe(struct platform_device *pdev)
+{
+	struct npcm_bpc *bpc;
+	struct device *dev;
+	u32 port;
+	int err;
+
+	dev = &pdev->dev;
+
+	bpc = devm_kzalloc(dev, sizeof(*bpc), GFP_KERNEL);
+	if (!bpc)
+		return -ENOMEM;
+
+	bpc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(bpc->base))
+		return PTR_ERR(bpc->base);
+
+	dev_set_drvdata(&pdev->dev, bpc);
+
+	err = of_property_read_u32_index(dev->of_node, "nuvoton,monitor-ports",
+					 0, &port);
+	if (err) {
+		dev_err(dev, "no monitor ports configured\n");
+		return -ENODEV;
+	}
+
+	bpc->en_dwcap =
+		of_property_read_bool(dev->of_node, "nuvoton,bpc-en-dwcapture");
+
+	bpc->dev = dev;
+
+	err = npcm_bpc_config_irq(bpc, pdev);
+	if (err)
+		return err;
+
+	err = npcm_enable_bpc(bpc, dev, 0, port);
+	if (err) {
+		dev_err(dev, "Enable BIOS post code I/O port 0 failed\n");
+		return err;
+	}
+
+	/*
+	 * Configuration of second BPC channel port is optional
+	 * Double-Word Capture ignoring address 2
+	 */
+	if (!bpc->en_dwcap) {
+		if (of_property_read_u32_index(dev->of_node,
+					       "nuvoton,monitor-ports", 1,
+					       &port) == 0) {
+			err = npcm_enable_bpc(bpc, dev, 1, port);
+			if (err) {
+				dev_err(dev, "Enable BIOS post code I/O port 1 failed, disable I/O port 0\n");
+				npcm_disable_bpc(bpc, 0);
+				return err;
+			}
+		}
+	}
+
+	pr_info("NPCM BIOS Post Code probe\n");
+
+	return err;
+}
+
+static int npcm_bpc_remove(struct platform_device *pdev)
+{
+	struct npcm_bpc *bpc = dev_get_drvdata(&pdev->dev);
+	u8 reg_en;
+
+	reg_en = ioread8(bpc->base + NPCM_BPCFEN_REG);
+
+	if (reg_en & FIFO_IOADDR1_ENABLE)
+		npcm_disable_bpc(bpc, 0);
+	if (reg_en & FIFO_IOADDR2_ENABLE)
+		npcm_disable_bpc(bpc, 1);
+
+	return 0;
+}
+
+static const struct of_device_id npcm_bpc_match[] = {
+	{ .compatible = "nuvoton,npcm-bpc" },
+	{ },
+};
+
+static struct platform_driver npcm_bpc_driver = {
+	.driver = {
+		.name		= DEVICE_NAME,
+		.of_match_table = npcm_bpc_match,
+	},
+	.probe = npcm_bpc_probe,
+	.remove = npcm_bpc_remove,
+};
+
+module_platform_driver(npcm_bpc_driver);
+
+MODULE_DEVICE_TABLE(of, npcm_bpc_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_DESCRIPTION("NPCM BIOS post code monitoring device driver");
-- 
2.34.1