[linux dev-4.19 08/11] misc: mbox: add npcm7xx pci mailbox driver
Tomer Maimon
tmaimon77 at gmail.com
Sun Dec 16 22:00:32 AEDT 2018
Add Nuvoton BMC NPCM7XX PCI Mailbox driver.
Signed-off-by: Tomer Maimon <tmaimon77 at gmail.com>
---
drivers/misc/Kconfig | 7 +
drivers/misc/Makefile | 1 +
drivers/misc/npcm7xx-pci-mbox.c | 288 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 296 insertions(+)
create mode 100644 drivers/misc/npcm7xx-pci-mbox.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index c0cbd68238cf..0ced167d1f01 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -528,6 +528,13 @@ config NPCM7XX_LPC_BPC
interface which allows the BMC to monitoring and save
the data written by the host to an arbitrary LPC I/O port.
+config NPCM7XX_PCI_MBOX
+ tristate "NPCM7xx PCI Mailbox Controller"
+ depends on (ARCH_NPCM7XX || COMPILE_TEST) && REGMAP && MFD_SYSCON
+ ---help---
+ Expose the NPCM750/730/715/705 PCI MBOX registers found on
+ Nuvoton SOCs to userspace.
+
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 2dc74726e3b0..768278b059c3 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o
obj-$(CONFIG_OCXL) += ocxl/
obj-$(CONFIG_MISC_RTSX) += cardreader/
obj-$(CONFIG_NPCM7XX_LPC_BPC) += npcm7xx-lpc-bpc.o
+obj-$(CONFIG_NPCM7XX_PCI_MBOX) += npcm7xx-pci-mbox.o
diff --git a/drivers/misc/npcm7xx-pci-mbox.c b/drivers/misc/npcm7xx-pci-mbox.c
new file mode 100644
index 000000000000..4720510d4160
--- /dev/null
+++ b/drivers/misc/npcm7xx-pci-mbox.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2014-2018 Nuvoton Technology corporation.
+
+#include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define DEVICE_NAME "npcm7xx-pci-mbox"
+
+#define NPCM7XX_MBOX_BMBXSTAT 0x0
+#define NPCM7XX_MBOX_BMBXCTL 0x4
+#define NPCM7XX_MBOX_BMBXCMD 0x8
+
+#define NPCM7XX_MBOX_CIF_0 BIT(0)
+#define NPCM7XX_MBOX_CIE_0 BIT(0)
+#define NPCM7XX_MBOX_HIF_0 BIT(0)
+
+#define NPCM7XX_MBOX_ALL_CIF GENMASK(7, 0)
+#define NPCM7XX_MBOX_ALL_CIE GENMASK(7, 0)
+#define NPCM7XX_MBOX_ALL_HIF GENMASK(7, 0)
+
+struct npcm7xx_mbox {
+ struct miscdevice miscdev;
+ struct regmap *regmap;
+ void __iomem *memory;
+ wait_queue_head_t queue;
+ spinlock_t lock; /* mbox access mutex */
+ bool cif0;
+ u32 max_buf_size;
+};
+
+static atomic_t npcm7xx_mbox_open_count = ATOMIC_INIT(0);
+
+static struct npcm7xx_mbox *file_mbox(struct file *file)
+{
+ return container_of(file->private_data, struct npcm7xx_mbox, miscdev);
+}
+
+static int npcm7xx_mbox_open(struct inode *inode, struct file *file)
+{
+ struct npcm7xx_mbox *mbox = file_mbox(file);
+
+ if (atomic_inc_return(&npcm7xx_mbox_open_count) == 1) {
+ /* enable mailbox interrupt */
+ regmap_update_bits(mbox->regmap, NPCM7XX_MBOX_BMBXCTL,
+ NPCM7XX_MBOX_ALL_CIE, NPCM7XX_MBOX_CIE_0);
+ return 0;
+ }
+
+ atomic_dec(&npcm7xx_mbox_open_count);
+ return -EBUSY;
+}
+
+static ssize_t npcm7xx_mbox_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct npcm7xx_mbox *mbox = file_mbox(file);
+ unsigned long flags;
+
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ if (count + *ppos > mbox->max_buf_size)
+ return -EINVAL;
+
+ if (file->f_flags & O_NONBLOCK) {
+ if (!mbox->cif0)
+ return -EAGAIN;
+ } else if (wait_event_interruptible(mbox->queue, mbox->cif0)) {
+ return -ERESTARTSYS;
+ }
+
+ spin_lock_irqsave(&mbox->lock, flags);
+
+ if (copy_to_user((void __user *)buf,
+ (const void *)(mbox->memory + *ppos), count)) {
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return -EFAULT;
+ }
+
+ mbox->cif0 = false;
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return count;
+}
+
+static ssize_t npcm7xx_mbox_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct npcm7xx_mbox *mbox = file_mbox(file);
+ unsigned long flags;
+
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+
+ if (count + *ppos > mbox->max_buf_size)
+ return -EINVAL;
+
+ spin_lock_irqsave(&mbox->lock, flags);
+
+ if (copy_from_user((void *)(mbox->memory + *ppos),
+ (void __user *)buf, count)) {
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return -EFAULT;
+ }
+
+ regmap_update_bits(mbox->regmap, NPCM7XX_MBOX_BMBXCMD,
+ NPCM7XX_MBOX_ALL_HIF, NPCM7XX_MBOX_HIF_0);
+
+ spin_unlock_irqrestore(&mbox->lock, flags);
+ return count;
+}
+
+static unsigned int npcm7xx_mbox_poll(struct file *file, poll_table *wait)
+{
+ struct npcm7xx_mbox *mbox = file_mbox(file);
+ unsigned int mask = 0;
+
+ poll_wait(file, &mbox->queue, wait);
+ if (mbox->cif0)
+ mask |= POLLIN;
+
+ return mask;
+}
+
+static int npcm7xx_mbox_release(struct inode *inode, struct file *file)
+{
+ atomic_dec(&npcm7xx_mbox_open_count);
+ return 0;
+}
+
+static const struct file_operations npcm7xx_mbox_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_seek_end_llseek,
+ .read = npcm7xx_mbox_read,
+ .write = npcm7xx_mbox_write,
+ .open = npcm7xx_mbox_open,
+ .release = npcm7xx_mbox_release,
+ .poll = npcm7xx_mbox_poll,
+};
+
+static irqreturn_t npcm7xx_mbox_irq(int irq, void *arg)
+{
+ struct npcm7xx_mbox *mbox = arg;
+ u32 val;
+
+ regmap_read(mbox->regmap, NPCM7XX_MBOX_BMBXSTAT, &val);
+ if ((val & NPCM7XX_MBOX_CIF_0) != NPCM7XX_MBOX_CIF_0)
+ return IRQ_NONE;
+
+ /*
+ * Leave the status bit set so that we know the data is for us,
+ * clear it once it has been read.
+ */
+ mbox->cif0 = true;
+
+ /* Mask it off, we'll clear it when we the data gets read */
+ regmap_write_bits(mbox->regmap, NPCM7XX_MBOX_BMBXSTAT,
+ NPCM7XX_MBOX_ALL_CIF, NPCM7XX_MBOX_CIF_0);
+
+ wake_up(&mbox->queue);
+
+ return IRQ_HANDLED;
+}
+
+static int npcm7xx_mbox_config_irq(struct npcm7xx_mbox *mbox,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int rc, irq;
+ u32 val;
+
+ /* Disable all register based interrupts */
+ regmap_update_bits(mbox->regmap, NPCM7XX_MBOX_BMBXCTL,
+ NPCM7XX_MBOX_ALL_CIE, 0);
+/*
+ * These registers are write one to clear. Clear them.
+ * Per spec, cleared bits should not be re-cleared.
+ * Need to read and clear needed bits only, instead of blindly clearing all.
+ */
+ regmap_read(mbox->regmap, NPCM7XX_MBOX_BMBXSTAT, &val);
+ val &= NPCM7XX_MBOX_ALL_CIF;
+
+ /* If any bit is set, write back to clear */
+ if (val)
+ regmap_write_bits(mbox->regmap, NPCM7XX_MBOX_BMBXSTAT,
+ NPCM7XX_MBOX_ALL_CIF, val);
+
+ irq = irq_of_parse_and_map(dev->of_node, 0);
+ if (!irq)
+ return -ENODEV;
+
+ rc = devm_request_irq(dev, irq, npcm7xx_mbox_irq, 0, DEVICE_NAME, mbox);
+ if (rc < 0) {
+ dev_err(dev, "Unable to request IRQ %d\n", irq);
+ return rc;
+ }
+
+ return 0;
+}
+
+static int npcm7xx_mbox_probe(struct platform_device *pdev)
+{
+ struct npcm7xx_mbox *mbox;
+ struct device *dev;
+ struct resource *res;
+ int rc;
+
+ dev = &pdev->dev;
+
+ mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+
+ dev_set_drvdata(&pdev->dev, mbox);
+
+ mbox->regmap = syscon_node_to_regmap(dev->of_node);
+ if (IS_ERR(mbox->regmap)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ return -ENODEV;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ mbox->memory = devm_ioremap_resource(dev, res);
+ if (IS_ERR(mbox->memory))
+ return PTR_ERR(mbox->memory);
+ mbox->max_buf_size = resource_size(res);
+
+ spin_lock_init(&mbox->lock);
+ init_waitqueue_head(&mbox->queue);
+
+ mbox->miscdev.minor = MISC_DYNAMIC_MINOR;
+ mbox->miscdev.name = DEVICE_NAME;
+ mbox->miscdev.fops = &npcm7xx_mbox_fops;
+ mbox->miscdev.parent = dev;
+ mbox->cif0 = false;
+ rc = misc_register(&mbox->miscdev);
+ if (rc) {
+ dev_err(dev, "Unable to register device\n");
+ return rc;
+ }
+
+ rc = npcm7xx_mbox_config_irq(mbox, pdev);
+ if (rc) {
+ dev_err(dev, "Failed to configure IRQ\n");
+ misc_deregister(&mbox->miscdev);
+ return rc;
+ }
+
+ pr_info("NPCM7xx PCI Mailbox probed\n");
+
+ return 0;
+}
+
+static int npcm7xx_mbox_remove(struct platform_device *pdev)
+{
+ struct npcm7xx_mbox *mbox = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&mbox->miscdev);
+
+ return 0;
+}
+
+static const struct of_device_id npcm7xx_mbox_match[] = {
+ { .compatible = "nuvoton,npcm750-pci-mbox" },
+ { },
+};
+
+static struct platform_driver npcm7xx_mbox_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = npcm7xx_mbox_match,
+ },
+ .probe = npcm7xx_mbox_probe,
+ .remove = npcm7xx_mbox_remove,
+};
+
+module_platform_driver(npcm7xx_mbox_driver);
+
+MODULE_DEVICE_TABLE(of, npcm7xx_mbox_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon at nuvoton.com>");
+MODULE_DESCRIPTION("NPCM7XX mailbox device driver");
--
2.14.1
More information about the openbmc
mailing list