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

Tomer Maimon
2019-04-15T12:13:26Z

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);
+ 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");
--
2.14.1