For MMIO, we have /dev/mem and the iomem command, but for I/O ports, we
only have the ioport command and no way to access I/O ports from shell.
Add a /dev/port device that interacts directly with I/O ports.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
drivers/misc/Kconfig | 4 ++
drivers/misc/Makefile | 1 +
drivers/misc/port.c | 158 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 163 insertions(+)
create mode 100644 drivers/misc/port.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 78c9c193d835..40482f8b88a7 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -24,6 +24,10 @@ config STATE_DRV
config DEV_MEM
bool "Generic memory I/O device (/dev/mem)"
+config DEV_PORT
+ bool "Generic port I/O device (/dev/port)"
+ depends on X86 || SANDBOX || COMPILE_TEST
+
config UBOOTVAR
bool "U-Boot environment storage"
depends on OFTREE
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 986f7b1b381b..871af85d5920 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_JTAG) += jtag.o
obj-$(CONFIG_SRAM) += sram.o
obj-$(CONFIG_STATE_DRV) += state.o
obj-$(CONFIG_DEV_MEM) += mem.o
+obj-$(CONFIG_DEV_PORT) += port.o
obj-$(CONFIG_UBOOTVAR) += ubootvar.o
obj-$(CONFIG_STARFIVE_PWRSEQ) += starfive-pwrseq.o
obj-$(CONFIG_STORAGE_BY_UUID) += storage-by-uuid.o
diff --git a/drivers/misc/port.c b/drivers/misc/port.c
new file mode 100644
index 000000000000..ddc443eb16df
--- /dev/null
+++ b/drivers/misc/port.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>, Pengutronix
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <fcntl.h>
+#include <init.h>
+
+static ssize_t port_read(struct cdev *cdev, void *buf, size_t count, loff_t offset,
+ unsigned long flags)
+{
+ struct device *dev = cdev->dev;
+ ssize_t size;
+ int rwsize = (flags & (O_RWSIZE_1 | O_RWSIZE_2 | O_RWSIZE_4));
+
+ if (!dev)
+ return -1;
+
+
+ if (!dev || dev->num_resources < 1)
+ return -1;
+
+ if (resource_size(&dev->resource[0]) > 0 || offset != 0)
+ count = min_t(size_t, count,
+ resource_size(&dev->resource[0]) - offset);
+
+ size = count;
+
+ /* no rwsize specification given. Use maximum */
+ if (!rwsize)
+ rwsize = 4;
+
+ rwsize = rwsize >> O_RWSIZE_SHIFT;
+
+ count = ALIGN_DOWN(count, rwsize);
+
+ while (count) {
+ switch (rwsize) {
+ case 1:
+ *((u8 *)buf) = inb(offset);
+ break;
+ case 2:
+ *((u16 *)buf) = inw(offset);
+ break;
+ case 4:
+ *((u32 *)buf) = inl(offset);
+ break;
+ }
+ buf += rwsize;
+ offset += rwsize;
+ count -= rwsize;
+ }
+
+ return size;
+}
+
+static ssize_t port_write(struct cdev *cdev, const void *buf, size_t count,
+ loff_t offset, unsigned long flags)
+{
+ struct device *dev = cdev->dev;
+ ssize_t size;
+ int rwsize = (flags & (O_RWSIZE_1 | O_RWSIZE_2 | O_RWSIZE_4));
+
+ if (!dev)
+ return -1;
+
+ if (!dev || dev->num_resources < 1)
+ return -1;
+
+ if (resource_size(&dev->resource[0]) > 0 || offset != 0)
+ count = min_t(size_t, count, resource_size(&dev->resource[0]) - offset);
+ size = count;
+
+ /* no rwsize specification given. Use maximum */
+ if (!rwsize)
+ rwsize = 4;
+
+ rwsize = rwsize >> O_RWSIZE_SHIFT;
+
+ count = ALIGN_DOWN(count, rwsize);
+
+ while (count) {
+ switch (rwsize) {
+ case 1:
+ outb(*((u8 *)buf), offset);
+ break;
+ case 2:
+ outw(*((u16 *)buf), offset);
+ break;
+ case 4:
+ outl(*((u32 *)buf), offset);
+ break;
+ }
+ buf += rwsize;
+ offset += rwsize;
+ count -= rwsize;
+ }
+
+ return size;
+}
+
+static struct cdev_operations portops = {
+ .read = port_read,
+ .write = port_write,
+};
+
+static int port_probe(struct device *dev)
+{
+ struct cdev *cdev;
+
+ cdev = xzalloc(sizeof (*cdev));
+ dev->priv = cdev;
+
+ cdev->name = (char*)dev->resource[0].name;
+ cdev->size = resource_size(&dev->resource[0]);
+
+ cdev->ops = &portops;
+ cdev->dev = dev;
+
+ devfs_create(cdev);
+
+ return 0;
+}
+
+static struct driver port_drv = {
+ .name = "port",
+ .probe = port_probe,
+};
+
+static int port_init(void)
+{
+ struct device *dev;
+ struct resource res = {
+ .start = 0,
+ .end = IO_SPACE_LIMIT,
+ .flags = IORESOURCE_IO,
+ .name = "port",
+ };
+ int ret;
+
+ dev = device_alloc("port", DEVICE_ID_DYNAMIC);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->resource = xmemdup(&res, sizeof(res));
+ dev->num_resources = 1;
+
+ ret = platform_device_register(dev);
+ if (ret)
+ return ret;
+
+ pr_notice("I/O port base %p\n", PCI_IOBASE);
+
+ return platform_driver_register(&port_drv);
+}
+device_initcall(port_init);
--
2.39.2
