diff options
Diffstat (limited to 'drivers/misc/aspeed-lpc-snoop.c')
| -rw-r--r-- | drivers/misc/aspeed-lpc-snoop.c | 349 |
1 files changed, 0 insertions, 349 deletions
diff --git a/drivers/misc/aspeed-lpc-snoop.c b/drivers/misc/aspeed-lpc-snoop.c deleted file mode 100644 index 2feb4347d67f..000000000000 --- a/drivers/misc/aspeed-lpc-snoop.c +++ /dev/null @@ -1,349 +0,0 @@ -/* - * Copyright 2017 Google Inc - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - * Provides a simple driver to control the ASPEED LPC snoop interface which - * allows the BMC to listen on and save the data written by - * the host to an arbitrary LPC I/O port. - * - * Typically used by the BMC to "watch" host boot progress via port - * 0x80 writes made by the BIOS during the boot process. - */ - -#include <linux/bitops.h> -#include <linux/interrupt.h> -#include <linux/fs.h> -#include <linux/kfifo.h> -#include <linux/mfd/syscon.h> -#include <linux/miscdevice.h> -#include <linux/module.h> -#include <linux/of.h> -#include <linux/of_device.h> -#include <linux/platform_device.h> -#include <linux/poll.h> -#include <linux/regmap.h> - -#define DEVICE_NAME "aspeed-lpc-snoop" - -#define NUM_SNOOP_CHANNELS 2 -#define SNOOP_FIFO_SIZE 2048 - -#define HICR5 0x0 -#define HICR5_EN_SNP0W BIT(0) -#define HICR5_ENINT_SNP0W BIT(1) -#define HICR5_EN_SNP1W BIT(2) -#define HICR5_ENINT_SNP1W BIT(3) - -#define HICR6 0x4 -#define HICR6_STR_SNP0W BIT(0) -#define HICR6_STR_SNP1W BIT(1) -#define SNPWADR 0x10 -#define SNPWADR_CH0_MASK GENMASK(15, 0) -#define SNPWADR_CH0_SHIFT 0 -#define SNPWADR_CH1_MASK GENMASK(31, 16) -#define SNPWADR_CH1_SHIFT 16 -#define SNPWDR 0x14 -#define SNPWDR_CH0_MASK GENMASK(7, 0) -#define SNPWDR_CH0_SHIFT 0 -#define SNPWDR_CH1_MASK GENMASK(15, 8) -#define SNPWDR_CH1_SHIFT 8 -#define HICRB 0x80 -#define HICRB_ENSNP0D BIT(14) -#define HICRB_ENSNP1D BIT(15) - -struct aspeed_lpc_snoop_model_data { - /* The ast2400 has bits 14 and 15 as reserved, whereas the ast2500 - * can use them. - */ - unsigned int has_hicrb_ensnp; -}; - -struct aspeed_lpc_snoop_channel { - struct kfifo fifo; - wait_queue_head_t wq; - struct miscdevice miscdev; -}; - -struct aspeed_lpc_snoop { - struct regmap *regmap; - int irq; - struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS]; -}; - -static struct aspeed_lpc_snoop_channel *snoop_file_to_chan(struct file *file) -{ - return container_of(file->private_data, - struct aspeed_lpc_snoop_channel, - miscdev); -} - -static ssize_t snoop_file_read(struct file *file, char __user *buffer, - size_t count, loff_t *ppos) -{ - struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file); - unsigned int copied; - int ret = 0; - - if (kfifo_is_empty(&chan->fifo)) { - if (file->f_flags & O_NONBLOCK) - return -EAGAIN; - ret = wait_event_interruptible(chan->wq, - !kfifo_is_empty(&chan->fifo)); - if (ret == -ERESTARTSYS) - return -EINTR; - } - ret = kfifo_to_user(&chan->fifo, buffer, count, &copied); - - return ret ? ret : copied; -} - -static unsigned int snoop_file_poll(struct file *file, - struct poll_table_struct *pt) -{ - struct aspeed_lpc_snoop_channel *chan = snoop_file_to_chan(file); - - poll_wait(file, &chan->wq, pt); - return !kfifo_is_empty(&chan->fifo) ? POLLIN : 0; -} - -static const struct file_operations snoop_fops = { - .owner = THIS_MODULE, - .read = snoop_file_read, - .poll = snoop_file_poll, - .llseek = noop_llseek, -}; - -/* Save a byte to a FIFO and discard the oldest byte if FIFO is full */ -static void put_fifo_with_discard(struct aspeed_lpc_snoop_channel *chan, u8 val) -{ - if (!kfifo_initialized(&chan->fifo)) - return; - if (kfifo_is_full(&chan->fifo)) - kfifo_skip(&chan->fifo); - kfifo_put(&chan->fifo, val); - wake_up_interruptible(&chan->wq); -} - -static irqreturn_t aspeed_lpc_snoop_irq(int irq, void *arg) -{ - struct aspeed_lpc_snoop *lpc_snoop = arg; - u32 reg, data; - - if (regmap_read(lpc_snoop->regmap, HICR6, ®)) - return IRQ_NONE; - - /* Check if one of the snoop channels is interrupting */ - reg &= (HICR6_STR_SNP0W | HICR6_STR_SNP1W); - if (!reg) - return IRQ_NONE; - - /* Ack pending IRQs */ - regmap_write(lpc_snoop->regmap, HICR6, reg); - - /* Read and save most recent snoop'ed data byte to FIFO */ - regmap_read(lpc_snoop->regmap, SNPWDR, &data); - - if (reg & HICR6_STR_SNP0W) { - u8 val = (data & SNPWDR_CH0_MASK) >> SNPWDR_CH0_SHIFT; - - put_fifo_with_discard(&lpc_snoop->chan[0], val); - } - if (reg & HICR6_STR_SNP1W) { - u8 val = (data & SNPWDR_CH1_MASK) >> SNPWDR_CH1_SHIFT; - - put_fifo_with_discard(&lpc_snoop->chan[1], val); - } - - return IRQ_HANDLED; -} - -static int aspeed_lpc_snoop_config_irq(struct aspeed_lpc_snoop *lpc_snoop, - struct platform_device *pdev) -{ - struct device *dev = &pdev->dev; - int rc; - - lpc_snoop->irq = platform_get_irq(pdev, 0); - if (!lpc_snoop->irq) - return -ENODEV; - - rc = devm_request_irq(dev, lpc_snoop->irq, - aspeed_lpc_snoop_irq, IRQF_SHARED, - DEVICE_NAME, lpc_snoop); - if (rc < 0) { - dev_warn(dev, "Unable to request IRQ %d\n", lpc_snoop->irq); - lpc_snoop->irq = 0; - return rc; - } - - return 0; -} - -static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop, - struct device *dev, - int channel, u16 lpc_port) -{ - int rc = 0; - u32 hicr5_en, snpwadr_mask, snpwadr_shift, hicrb_en; - const struct aspeed_lpc_snoop_model_data *model_data = - of_device_get_match_data(dev); - - init_waitqueue_head(&lpc_snoop->chan[channel].wq); - /* Create FIFO datastructure */ - rc = kfifo_alloc(&lpc_snoop->chan[channel].fifo, - SNOOP_FIFO_SIZE, GFP_KERNEL); - if (rc) - return rc; - - lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR; - lpc_snoop->chan[channel].miscdev.name = - devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel); - lpc_snoop->chan[channel].miscdev.fops = &snoop_fops; - lpc_snoop->chan[channel].miscdev.parent = dev; - rc = misc_register(&lpc_snoop->chan[channel].miscdev); - if (rc) - return rc; - - /* Enable LPC snoop channel at requested port */ - switch (channel) { - case 0: - hicr5_en = HICR5_EN_SNP0W | HICR5_ENINT_SNP0W; - snpwadr_mask = SNPWADR_CH0_MASK; - snpwadr_shift = SNPWADR_CH0_SHIFT; - hicrb_en = HICRB_ENSNP0D; - break; - case 1: - hicr5_en = HICR5_EN_SNP1W | HICR5_ENINT_SNP1W; - snpwadr_mask = SNPWADR_CH1_MASK; - snpwadr_shift = SNPWADR_CH1_SHIFT; - hicrb_en = HICRB_ENSNP1D; - break; - default: - return -EINVAL; - } - - regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en); - regmap_update_bits(lpc_snoop->regmap, SNPWADR, snpwadr_mask, - lpc_port << snpwadr_shift); - if (model_data->has_hicrb_ensnp) - regmap_update_bits(lpc_snoop->regmap, HICRB, - hicrb_en, hicrb_en); - - return rc; -} - -static void aspeed_lpc_disable_snoop(struct aspeed_lpc_snoop *lpc_snoop, - int channel) -{ - switch (channel) { - case 0: - regmap_update_bits(lpc_snoop->regmap, HICR5, - HICR5_EN_SNP0W | HICR5_ENINT_SNP0W, - 0); - break; - case 1: - regmap_update_bits(lpc_snoop->regmap, HICR5, - HICR5_EN_SNP1W | HICR5_ENINT_SNP1W, - 0); - break; - default: - return; - } - - kfifo_free(&lpc_snoop->chan[channel].fifo); - misc_deregister(&lpc_snoop->chan[channel].miscdev); -} - -static int aspeed_lpc_snoop_probe(struct platform_device *pdev) -{ - struct aspeed_lpc_snoop *lpc_snoop; - struct device *dev; - u32 port; - int rc; - - dev = &pdev->dev; - - lpc_snoop = devm_kzalloc(dev, sizeof(*lpc_snoop), GFP_KERNEL); - if (!lpc_snoop) - return -ENOMEM; - - lpc_snoop->regmap = syscon_node_to_regmap( - pdev->dev.parent->of_node); - if (IS_ERR(lpc_snoop->regmap)) { - dev_err(dev, "Couldn't get regmap\n"); - return -ENODEV; - } - - dev_set_drvdata(&pdev->dev, lpc_snoop); - - 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; - } - - rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev); - if (rc) - return rc; - - rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port); - if (rc) - return rc; - - /* Configuration of 2nd snoop channel port is optional */ - if (of_property_read_u32_index(dev->of_node, "snoop-ports", - 1, &port) == 0) { - rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port); - if (rc) - aspeed_lpc_disable_snoop(lpc_snoop, 0); - } - - return rc; -} - -static int aspeed_lpc_snoop_remove(struct platform_device *pdev) -{ - struct aspeed_lpc_snoop *lpc_snoop = dev_get_drvdata(&pdev->dev); - - /* Disable both snoop channels */ - aspeed_lpc_disable_snoop(lpc_snoop, 0); - aspeed_lpc_disable_snoop(lpc_snoop, 1); - - return 0; -} - -static const struct aspeed_lpc_snoop_model_data ast2400_model_data = { - .has_hicrb_ensnp = 0, -}; - -static const struct aspeed_lpc_snoop_model_data ast2500_model_data = { - .has_hicrb_ensnp = 1, -}; - -static const struct of_device_id aspeed_lpc_snoop_match[] = { - { .compatible = "aspeed,ast2400-lpc-snoop", - .data = &ast2400_model_data }, - { .compatible = "aspeed,ast2500-lpc-snoop", - .data = &ast2500_model_data }, - { }, -}; - -static struct platform_driver aspeed_lpc_snoop_driver = { - .driver = { - .name = DEVICE_NAME, - .of_match_table = aspeed_lpc_snoop_match, - }, - .probe = aspeed_lpc_snoop_probe, - .remove = aspeed_lpc_snoop_remove, -}; - -module_platform_driver(aspeed_lpc_snoop_driver); - -MODULE_DEVICE_TABLE(of, aspeed_lpc_snoop_match); -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Robert Lippert <rlippert@google.com>"); -MODULE_DESCRIPTION("Linux driver to control Aspeed LPC snoop functionality"); |