Re: [PATCH v1 2/2] misc: npcm: add NPCM LPC BPC driver

Guenter Roeck
2019-04-15T13:21:10Z

On 4/15/19 5:12 AM, Tomer Maimon wrote:
> Add Nuvoton BMC NPCM BIOS post code (BPC) driver.
>
> The NPCM BPC monitoring two I/O address written by
> the host on the Low Pin Count (LPC) bus, the capure
> data stored in 128-word FIFO.
>
> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> ---
> drivers/misc/Kconfig | 8 +
> drivers/misc/Makefile | 1 +
> drivers/misc/npcm-lpc-bpc-snoop.c | 393 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 402 insertions(+)
> create mode 100644 drivers/misc/npcm-lpc-bpc-snoop.c
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 42ab8ec92a04..320a1d0083d2 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -532,6 +532,14 @@ config PVPANIC
> a paravirtualized device provided by QEMU; it lets a virtual machine
> (guest) communicate panic events to the host.
>
> +config NPCM_LPC_BPC_SNOOP
> + tristate "NPCM LPC BIOS Post Code snoop support"
> + depends on (ARCH_NPCM || COMPILE_TEST)
> + help
> + Provides a NPCM BMC driver to control the LPC BIOS Post Code
> + interface which allows the BMC to monitoring and save
> + the data written by the host to an arbitrary LPC I/O port.
> +
> source "drivers/misc/c2port/Kconfig"
> source "drivers/misc/eeprom/Kconfig"
> source "drivers/misc/cb710/Kconfig"
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index d5b7d3404dc7..5dd0bff75b60 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -59,5 +59,6 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
> obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o
> obj-$(CONFIG_OCXL) += ocxl/
> obj-y += cardreader/
> +obj-$(CONFIG_NPCM_LPC_BPC_SNOOP) += npcm-lpc-bpc-snoop.o
> obj-$(CONFIG_PVPANIC) += pvpanic.o
> obj-$(CONFIG_HABANA_AI) += habanalabs/
> diff --git a/drivers/misc/npcm-lpc-bpc-snoop.c b/drivers/misc/npcm-lpc-bpc-snoop.c
> new file mode 100644
> index 000000000000..851994184076
> --- /dev/null
> +++ b/drivers/misc/npcm-lpc-bpc-snoop.c
> @@ -0,0 +1,393 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2014-2018 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-lpc-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 regiser data*/
> +#define FIFO_IOADDR1_ENABLE 0x80
> +#define FIFO_IOADDR2_ENABLE 0x40
> +
> +/* BPC interface package and structure definition */
> +#define BPC_KFIFO_SIZE 0x400
> +
> +/*BPC regiser 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;
> + 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 *lpc_bpc = chan->data;
> + unsigned int copied;
> + int ret = 0;
> + int cond_size = 1;
> +
> + if (lpc_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 |= POLLIN;
> +
> + if (chan->host_reset) {
> + mask |= 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 *lpc_bpc = arg;
> + u8 fifo_st;
> + u8 host_st;
> + u8 addr_index = 0;
> + u8 Data;
> + u8 padzero[3] = {0};
> + u8 last_addr_bit = 0;
> + bool isr_flag = false;
> +
> + fifo_st = ioread8(lpc_bpc->base + NPCM_BPCFSTAT_REG);
> + while (FIFO_DATA_VALID & fifo_st) {
> + /* If dwcapture enabled only channel 0 (FIFO 0) used */
> + if (!lpc_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(lpc_bpc->base + NPCM_BPCFDATA_REG);
> + if (kfifo_is_full(&lpc_bpc->ch[addr_index].fifo))
> + kfifo_skip(&lpc_bpc->ch[addr_index].fifo);
> + kfifo_put(&lpc_bpc->ch[addr_index].fifo, Data);
> + if (fifo_st & FIFO_OVERFLOW)
> + pr_info("BIOS Post Codes FIFO Overflow!!!\n");
> +
> + fifo_st = ioread8(lpc_bpc->base + NPCM_BPCFSTAT_REG);
> + if (lpc_bpc->en_dwcap && last_addr_bit) {
> + if ((fifo_st & FIFO_ADDR_DECODE) ||
> + ((FIFO_DATA_VALID & fifo_st) == 0)) {
> + while (kfifo_avail(&lpc_bpc->ch[addr_index].fifo) < DW_PAD_SIZE)
> + kfifo_skip(&lpc_bpc->ch[addr_index].fifo);
> + kfifo_in(&lpc_bpc->ch[addr_index].fifo,
> + padzero, DW_PAD_SIZE);
> + }
> + }
> + isr_flag = true;
> + }
> +
> + host_st = ioread8(lpc_bpc->base + NPCM_BPCFMSTAT_REG);
> + if (host_st & HOST_RESET_CHANGED) {
> + iowrite8(HOST_RESET_CHANGED,
> + lpc_bpc->base + NPCM_BPCFMSTAT_REG);
> + lpc_bpc->ch[addr_index].host_reset = true;
> + isr_flag = true;
> + }
> +
> + if (isr_flag) {
> + wake_up_interruptible(&lpc_bpc->ch[addr_index].wq);
> + return IRQ_HANDLED;
> + }
> +
> + return IRQ_NONE;
> +}
> +
> +static int npcm_bpc_config_irq(struct npcm_bpc *lpc_bpc,
> + struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + int rc;
> +
> + lpc_bpc->irq = platform_get_irq(pdev, 0);
> + if (lpc_bpc->irq < 0) {
> + dev_err(dev, "get IRQ failed\n");
> + return lpc_bpc->irq;
> + }
> +
> + rc = devm_request_irq(dev, lpc_bpc->irq,
> + npcm_bpc_irq, IRQF_SHARED,
> + DEVICE_NAME, lpc_bpc);
> + if (rc < 0) {
> + dev_warn(dev, "Unable to request IRQ %d\n", lpc_bpc->irq);
> + return rc;
> + }
> +
> + return 0;
> +}
> +
> +static int npcm_enable_bpc(struct npcm_bpc *lpc_bpc, struct device *dev,
> + int channel, u16 lpc_port)
> +{
> + int rc;
> + u8 addr_en, reg_en;
> +
> + init_waitqueue_head(&lpc_bpc->ch[channel].wq);
> +
> + rc = kfifo_alloc(&lpc_bpc->ch[channel].fifo,
> + BPC_KFIFO_SIZE, GFP_KERNEL);
> + if (rc)
> + return rc;
> +
> + lpc_bpc->ch[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
> + lpc_bpc->ch[channel].miscdev.name =
> + devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
> + lpc_bpc->ch[channel].miscdev.fops = &npcm_bpc_fops;
> + lpc_bpc->ch[channel].miscdev.parent = dev;
> + rc = misc_register(&lpc_bpc->ch[channel].miscdev);
> + if (rc)
> + return rc;
> +
> + lpc_bpc->ch[channel].data = lpc_bpc;
> + lpc_bpc->ch[channel].host_reset = false;
> +
> + /* Enable LPC snoop channel at requested port */
> + switch (channel) {
> + case 0:
> + addr_en = FIFO_IOADDR1_ENABLE;
> + iowrite8((u8)lpc_port & 0xFF,
> + lpc_bpc->base + NPCM_BPCFA1L_REG);
> + iowrite8((u8)(lpc_port >> 8),
> + lpc_bpc->base + NPCM_BPCFA1M_REG);
> + break;
> + case 1:
> + addr_en = FIFO_IOADDR2_ENABLE;
> + iowrite8((u8)lpc_port & 0xFF,
> + lpc_bpc->base + NPCM_BPCFA2L_REG);
> + iowrite8((u8)(lpc_port >> 8),
> + lpc_bpc->base + NPCM_BPCFA2M_REG);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + if (lpc_bpc->en_dwcap)
> + addr_en = FIFO_DWCAPTURE;
> +
> + /*
> + * Enable FIFO Ready Interrupt, FIFO Capture of I/O addr,
> + * and Host Reset
> + */
> + reg_en = ioread8(lpc_bpc->base + NPCM_BPCFEN_REG);
> + iowrite8(reg_en | addr_en | FIFO_READY_INT_ENABLE |
> + HOST_RESET_INT_ENABLE, lpc_bpc->base + NPCM_BPCFEN_REG);
> +
> + return 0;
> +}
> +
> +static void npcm_disable_bpc(struct npcm_bpc *lpc_bpc, int channel)
> +{
> + u8 reg_en;
> +
> + switch (channel) {
> + case 0:
> + reg_en = ioread8(lpc_bpc->base + NPCM_BPCFEN_REG);
> + if (lpc_bpc->en_dwcap)
> + iowrite8(reg_en & ~FIFO_DWCAPTURE,
> + lpc_bpc->base + NPCM_BPCFEN_REG);
> + else
> + iowrite8(reg_en & ~FIFO_IOADDR1_ENABLE,
> + lpc_bpc->base + NPCM_BPCFEN_REG);
> + break;
> + case 1:
> + reg_en = ioread8(lpc_bpc->base + NPCM_BPCFEN_REG);
> + iowrite8(reg_en & ~FIFO_IOADDR2_ENABLE,
> + lpc_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),
> + lpc_bpc->base + NPCM_BPCFEN_REG);
> +
> + kfifo_free(&lpc_bpc->ch[channel].fifo);
> + misc_deregister(&lpc_bpc->ch[channel].miscdev);
> +}
> +
> +static int npcm_bpc_probe(struct platform_device *pdev)
> +{
> + struct npcm_bpc *lpc_bpc;
> + struct resource *res;
> + struct device *dev;
> + u32 port;
> + int rc;
> +
> + dev = &pdev->dev;
> +
> + lpc_bpc = devm_kzalloc(dev, sizeof(*lpc_bpc), GFP_KERNEL);
> + if (!lpc_bpc)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(dev, "BIOS post code reg resource not found\n");
> + return -ENODEV;
> + }
> +
> + dev_dbg(dev, "BIOS post code base resource is %pR\n", res);
> + lpc_bpc->base = devm_ioremap_resource(dev, res);

Any reason for not using devm_platform_ioremap_resource() ?

Guenter

> + if (IS_ERR(lpc_bpc->base))
> + return PTR_ERR(lpc_bpc->base);
> +
> + dev_set_drvdata(&pdev->dev, lpc_bpc);
> +
> + rc = of_property_read_u32_index(dev->of_node, "snoop-ports", 0,
> + &port);
> + if (rc) {
> + dev_err(dev, "no snoop ports configured\n");
> + return -ENODEV;
> + }
> +
> + lpc_bpc->en_dwcap =
> + of_property_read_bool(dev->of_node, "nuvoton,lpc-en-dwcapture");
> +
> + rc = npcm_bpc_config_irq(lpc_bpc, pdev);
> + if (rc)
> + return rc;
> +
> + rc = npcm_enable_bpc(lpc_bpc, dev, 0, port);
> + if (rc) {
> + dev_err(dev, "Enable BIOS post code I/O port 0 failed\n");
> + return rc;
> + }
> +
> + /*
> + * Configuration of second BPC channel port is optional
> + * Double-Word Capture ignoring address 2
> + */
> + if (!lpc_bpc->en_dwcap) {
> + if (of_property_read_u32_index(dev->of_node, "snoop-ports",
> + 1, &port) == 0) {
> + rc = npcm_enable_bpc(lpc_bpc, dev, 1, port);
> + if (rc) {
> + dev_err(dev, "Enable BIOS post code I/O port 1 failed, disable I/O port 0\n");
> + npcm_disable_bpc(lpc_bpc, 0);
> + return rc;
> + }
> + }
> + }
> +
> + pr_info("NPCM BIOS post code probe\n");
> +
> + return rc;
> +}
> +
> +static int npcm_bpc_remove(struct platform_device *pdev)
> +{
> + struct npcm_bpc *lpc_bpc = dev_get_drvdata(&pdev->dev);
> + u8 reg_en;
> +
> + reg_en = ioread8(lpc_bpc->base + NPCM_BPCFEN_REG);
> +
> + if (reg_en & FIFO_IOADDR1_ENABLE)
> + npcm_disable_bpc(lpc_bpc, 0);
> + if (reg_en & FIFO_IOADDR2_ENABLE)
> + npcm_disable_bpc(lpc_bpc, 1);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id npcm_bpc_match[] = {
> + { .compatible = "nuvoton,npcm750-lpc-bpc-snoop" },
> + { },
> +};
> +
> +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("Linux driver to control NPCM LPC BIOS post code snooping");
>