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path: root/drivers/misc/mctp-lpc.c
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Diffstat (limited to 'drivers/misc/mctp-lpc.c')
-rw-r--r--drivers/misc/mctp-lpc.c443
1 files changed, 0 insertions, 443 deletions
diff --git a/drivers/misc/mctp-lpc.c b/drivers/misc/mctp-lpc.c
deleted file mode 100644
index 0228f6bbf1a7..000000000000
--- a/drivers/misc/mctp-lpc.c
+++ /dev/null
@@ -1,443 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Copyright (c) 2019, IBM Corp.
- */
-
-#include <linux/errno.h>
-#include <linux/fs.h>
-#include <linux/interrupt.h>
-#include <linux/io.h>
-#include <linux/mfd/syscon.h>
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/platform_device.h>
-#include <linux/poll.h>
-#include <linux/regmap.h>
-#include <linux/sched/signal.h>
-#include <linux/uaccess.h>
-#include <linux/wait.h>
-
-#define LPC_HICRB 0x100
-#define LPC_HICRB_IBFIF4 BIT(1)
-#define LPC_HICRB_LPC4E BIT(0)
-#define LPC_HICRC 0x104
-#define LPC_KCS4_IRQSEL_MASK GENMASK(7, 4)
-#define LPC_KCS4_IRQSEL_SHIFT 4
-#define LPC_KCS4_IRQTYPE_MASK GENMASK(3, 2)
-#define LPC_KCS4_IRQTYPE_SHIFT 2
-#define LPC_KCS4_IRQTYPE_LOW 0b00
-#define LPC_KCS4_IRQTYPE_HIGH 0b01
-#define LPC_KCS4_IRQTYPE_RSVD 0b10
-#define LPC_KCS4_IRQTYPE_RISING 0b11
-#define LPC_KCS4_OBF4_AUTO_CLR BIT(1)
-#define LPC_KCS4_IRQ_HOST BIT(0)
-#define LPC_LADR4 0x110
-#define LPC_IDR4 0x114
-#define LPC_ODR4 0x118
-#define LPC_STR4 0x11C
-#define STR4_IBF (1 << 1)
-#define STR4_OBF (1 << 0)
-
-#define HOST_ODR 0xca2
-#define HOST_STR 0xca3
-#define HOST_SERIRQ_ID 11
-#define HOST_SERIRQ_TYPE LPC_KCS4_IRQTYPE_LOW
-
-#define RX_BUF_SIZE 1024
-
-struct mctp_lpc {
- struct miscdevice miscdev;
- struct regmap *map;
-
- wait_queue_head_t rx;
- bool pending;
- u8 idr;
-};
-
-static irqreturn_t mctp_lpc_irq(int irq, void *data)
-{
- struct mctp_lpc *priv = data;
- unsigned long flags;
- unsigned int hicrb;
- struct device *dev;
- unsigned int str;
- irqreturn_t ret;
-
- dev = priv->miscdev.this_device;
-
- spin_lock_irqsave(&priv->rx.lock, flags);
-
- regmap_read(priv->map, LPC_STR4, &str);
- regmap_read(priv->map, LPC_HICRB, &hicrb);
-
- if ((str & STR4_IBF) && (hicrb & LPC_HICRB_IBFIF4)) {
- unsigned int val;
-
- if (priv->pending)
- dev_err(dev, "Storm brewing!");
-
- /* Mask the IRQ / Enter polling mode */
- dev_dbg(dev, "Received IRQ %d, disabling to provide back-pressure\n",
- irq);
- regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_IBFIF4, 0);
-
- /*
- * Extract the IDR4 value to ack the IRQ. Reading IDR clears
- * IBF and allows the host to write another value, however as
- * we have disabled IRQs the back-pressure is still applied
- * until userspace starts servicing the interface.
- */
- regmap_read(priv->map, LPC_IDR4, &val);
- priv->idr = val & 0xff;
- priv->pending = true;
-
- dev_dbg(dev, "Set pending, waking waiters\n");
- wake_up_locked(&priv->rx);
- ret = IRQ_HANDLED;
- } else {
- dev_dbg(dev, "LPC IRQ triggered, but not for us (str=0x%x, hicrb=0x%x)\n",
- str, hicrb);
- ret = IRQ_NONE;
- }
-
- spin_unlock_irqrestore(&priv->rx.lock, flags);
-
- return ret;
-}
-
-static inline struct mctp_lpc *to_mctp_lpc(struct file *filp)
-{
- return container_of(filp->private_data, struct mctp_lpc, miscdev);
-}
-
-static ssize_t mctp_lpc_read(struct file *filp, char __user *buf,
- size_t count, loff_t *ppos)
-{
- struct mctp_lpc *priv;
- struct device *dev;
- size_t remaining;
- ssize_t rc;
-
- priv = to_mctp_lpc(filp);
- dev = priv->miscdev.this_device;
-
- if (!count)
- return 0;
-
- if (count > 2 || *ppos > 1)
- return -EINVAL;
-
- remaining = count;
-
- spin_lock_irq(&priv->rx.lock);
- if (*ppos == 0) {
- unsigned int val;
- u8 str;
-
- /* YOLO blocking, non-block not supported */
- dev_dbg(dev, "Waiting for IBF\n");
- regmap_read(priv->map, LPC_STR4, &val);
- str = val & 0xff;
- rc = wait_event_interruptible_locked(priv->rx, (priv->pending || str & STR4_IBF));
- if (rc < 0)
- goto out;
-
- if (signal_pending(current)) {
- dev_dbg(dev, "Interrupted waiting for IBF\n");
- rc = -EINTR;
- goto out;
- }
-
- /*
- * Re-enable IRQs prior to possible read of IDR (which clears
- * IBF) to ensure we receive interrupts for subsequent writes
- * to IDR. Writes to IDR by the host should not occur while IBF
- * is set.
- */
- dev_dbg(dev, "Woken by IBF, enabling IRQ\n");
- regmap_update_bits(priv->map, LPC_HICRB, LPC_HICRB_IBFIF4,
- LPC_HICRB_IBFIF4);
-
- /* Read data out of IDR into internal storage if necessary */
- if (!priv->pending) {
- WARN(!(str & STR4_IBF), "Unknown reason for wakeup!");
-
- /* Extract the IDR4 value to ack the IRQ */
- regmap_read(priv->map, LPC_IDR4, &val);
- priv->idr = val & 0xff;
- }
-
- /* Copy data from internal storage to userspace */
- if (copy_to_user(buf, &priv->idr, sizeof(priv->idr))) {
- rc = -EFAULT;
- goto out;
- }
-
- /* We're done consuming the internally stored value */
- priv->pending = false;
-
- remaining--;
- buf++;
- }
-
- if (remaining) {
- /* Either:
- *
- * 1. (count == 1 && *ppos == 1)
- * 2. (count == 2 && *ppos == 0)
- */
- unsigned int val;
- u8 str;
-
- regmap_read(priv->map, LPC_STR4, &val);
- str = val & 0xff;
- if (*ppos == 0 || priv->pending)
- /*
- * If we got this far with `*ppos == 0` then we've read
- * data out of IDR, so set IBF when reporting back to
- * userspace so userspace knows the IDR value is valid.
- */
- str |= STR4_IBF;
-
- dev_dbg(dev, "Read status 0x%x\n", str);
- if (copy_to_user(buf, &str, sizeof(str))) {
- rc = -EFAULT;
- goto out;
- }
-
- remaining--;
- }
-
- WARN_ON(remaining);
-
- rc = count;
-
-out:
- spin_unlock_irq(&priv->rx.lock);
-
- return rc;
-}
-
-static ssize_t mctp_lpc_write(struct file *filp, const char __user *buf,
- size_t count, loff_t *ppos)
-{
- uint8_t _data[2], *data = &_data[0];
- struct mctp_lpc *priv;
- struct device *dev;
- size_t remaining;
- unsigned int str;
-
- priv = to_mctp_lpc(filp);
- dev = priv->miscdev.this_device;
-
- if (!count)
- return count;
-
- if (count > 2)
- return -EINVAL;
-
- if (*ppos >= 2)
- return -EINVAL;
-
- if (*ppos + count > 2)
- return -EINVAL;
-
- if (copy_from_user(data, buf, count))
- return -EFAULT;
-
- remaining = count;
-
- if (*ppos == 0) {
- /* Wait until OBF is clear - we don't get an IRQ */
- dev_dbg(dev, "Waiting for OBF to clear\n");
- for (;;) {
- if (signal_pending(current))
- return -EINTR;
-
- regmap_read(priv->map, LPC_STR4, &str);
- if (!(str & STR4_OBF))
- break;
-
- msleep(1);
- }
-
- dev_dbg(dev, "Writing 0x%x to ODR\n", *data);
- regmap_write(priv->map, LPC_ODR4, *data);
- remaining--;
- data++;
- }
-
- if (remaining) {
- if (!(*data & STR4_OBF))
- dev_err(dev, "Clearing OBF with status write: 0x%x\n",
- *data);
- dev_dbg(dev, "Writing status 0x%x\n", *data);
- regmap_write(priv->map, LPC_STR4, *data);
- remaining--;
- }
-
- WARN_ON(remaining);
-
- regmap_read(priv->map, LPC_STR4, &str);
- dev_dbg(dev, "Triggering SerIRQ (current str=0x%x)\n", str);
-
- /*
- * Trigger Host IRQ on ODR write. Do this after any STR write in case
- * we need to write ODR to indicate an STR update (which we do).
- */
- if (*ppos == 0)
- regmap_update_bits(priv->map, LPC_HICRC, LPC_KCS4_IRQ_HOST,
- LPC_KCS4_IRQ_HOST);
-
- return count;
-}
-
-static __poll_t mctp_lpc_poll(struct file *filp, poll_table *wait)
-{
- struct mctp_lpc *priv;
- struct device *dev;
- unsigned int val;
- bool ibf;
-
- priv = to_mctp_lpc(filp);
- dev = priv->miscdev.this_device;
-
- regmap_read(priv->map, LPC_STR4, &val);
-
- spin_lock_irq(&priv->rx.lock);
-
- ibf = priv->pending || val & STR4_IBF;
-
- if (!ibf) {
- dev_dbg(dev, "Polling on IBF\n");
-
- spin_unlock_irq(&priv->rx.lock);
-
- poll_wait(filp, &priv->rx, wait);
- if (signal_pending(current)) {
- dev_dbg(dev, "Polling IBF was interrupted\n");
- goto out;
- }
-
- spin_lock_irq(&priv->rx.lock);
-
- regmap_read(priv->map, LPC_STR4, &val);
-
- ibf = priv->pending || val & STR4_IBF;
- }
-
- spin_unlock_irq(&priv->rx.lock);
-
-out:
- dev_dbg(dev, "Polled IBF state: %s\n", ibf ? "set" : "clear");
-
- return ibf ? EPOLLIN : 0;
-}
-
-static const struct file_operations mctp_lpc_fops = {
- .owner = THIS_MODULE,
- .llseek = no_seek_end_llseek,
- .read = mctp_lpc_read,
- .write = mctp_lpc_write,
- .poll = mctp_lpc_poll,
-};
-
-static int mctp_lpc_probe(struct platform_device *pdev)
-{
- struct device *dev = &pdev->dev;
- unsigned int mask, val;
- struct mctp_lpc *priv;
- int irq;
- int rc;
-
- priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
-
- priv->map = syscon_node_to_regmap(dev->parent->of_node);
- if (IS_ERR(priv->map)) {
- dev_err(dev, "Couldn't get regmap\n");
- return -ENODEV;
- }
-
- /*
- * Set the LPC address. Simultaneously, test our MMIO regmap works. All
- * subsequent accesses are assumed to work
- */
- rc = regmap_write(priv->map, LPC_LADR4, ((HOST_STR) << 16) | HOST_ODR);
- if (rc < 0)
- return rc;
-
- /* Set up the SerIRQ */
- mask = LPC_KCS4_IRQSEL_MASK
- | LPC_KCS4_IRQTYPE_MASK
- | LPC_KCS4_OBF4_AUTO_CLR;
- val = (HOST_SERIRQ_ID << LPC_KCS4_IRQSEL_SHIFT)
- | (HOST_SERIRQ_TYPE << LPC_KCS4_IRQTYPE_SHIFT);
- val &= ~LPC_KCS4_OBF4_AUTO_CLR; /* Unnecessary, just documentation */
- regmap_update_bits(priv->map, LPC_HICRC, mask, val);
-
- /* Trigger waiters from IRQ */
- init_waitqueue_head(&priv->rx);
-
- dev_set_drvdata(dev, priv);
-
- /* Set up the miscdevice */
- priv->miscdev.minor = MISC_DYNAMIC_MINOR;
- priv->miscdev.name = "mctp0";
- priv->miscdev.fops = &mctp_lpc_fops;
-
- /* Configure the IRQ handler */
- irq = platform_get_irq(pdev, 0);
- if (irq < 0)
- return irq;
-
- rc = devm_request_irq(dev, irq, mctp_lpc_irq, IRQF_SHARED,
- dev_name(dev), priv);
- if (rc < 0)
- return rc;
-
- /* Register the device */
- rc = misc_register(&priv->miscdev);
- if (rc) {
- dev_err(dev, "Unable to register device\n");
- return rc;
- }
-
- /* Enable the channel */
- regmap_update_bits(priv->map, LPC_HICRB,
- LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E,
- LPC_HICRB_IBFIF4 | LPC_HICRB_LPC4E);
-
- return 0;
-}
-
-static int mctp_lpc_remove(struct platform_device *pdev)
-{
- struct mctp_lpc *ctx = dev_get_drvdata(&pdev->dev);
-
- misc_deregister(&ctx->miscdev);
-
- return 0;
-}
-
-static const struct of_device_id mctp_lpc_match[] = {
- { .compatible = "openbmc,mctp-lpc" },
- { }
-};
-MODULE_DEVICE_TABLE(of, mctp_lpc_match);
-
-static struct platform_driver mctp_lpc = {
- .driver = {
- .name = "mctp-lpc",
- .of_match_table = mctp_lpc_match,
- },
- .probe = mctp_lpc_probe,
- .remove = mctp_lpc_remove,
-};
-module_platform_driver(mctp_lpc);
-
-MODULE_LICENSE("GPL v2+");
-MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
-MODULE_DESCRIPTION("OpenBMC MCTP LPC binding on ASPEED KCS");
generated by cgit v1.2.3 (git 2.39.0) at 2024-06-11 08:34:56 +0300