[PATCH 09/11] misc: Versatile Express system registers driver
Pawel Moll
pawel.moll at arm.com
Mon Sep 3 12:25:29 EDT 2012
This is a platform driver for Versatile Express' "system
register" block. It's a random collection of registers providing
the following functionality:
- low level platform functions like board ID access; in order to
use those, the driver must be initialized early, either statically
or based on the DT
- config bus bridge via "system control" interface; as the response
from the controller does not generate interrupt (yet), the status
register is periodically polled using a timer
- pseudo GPIO lines providing MMC card status and Flash WP#
signal control
- LED interface for a set of 8 LEDs on the motherboard, with
"heartbeat" and "mmc0" as default triggers for 2 of them
Signed-off-by: Pawel Moll <pawel.moll at arm.com>
---
drivers/misc/vexpress/Makefile | 1 +
drivers/misc/vexpress/sysreg.c | 423 ++++++++++++++++++++++++++++++++++++++++
include/linux/vexpress.h | 13 ++
3 files changed, 437 insertions(+)
create mode 100644 drivers/misc/vexpress/sysreg.c
diff --git a/drivers/misc/vexpress/Makefile b/drivers/misc/vexpress/Makefile
index d83d6b6..45af621 100644
--- a/drivers/misc/vexpress/Makefile
+++ b/drivers/misc/vexpress/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_VEXPRESS_CONFIG_BUS) += config_bus.o
obj-$(CONFIG_VEXPRESS_CONFIG_BUS) += display.o
obj-$(CONFIG_VEXPRESS_CONFIG_BUS) += reset.o
+obj-$(CONFIG_VEXPRESS_CONFIG_BUS) += sysreg.o
diff --git a/drivers/misc/vexpress/sysreg.c b/drivers/misc/vexpress/sysreg.c
new file mode 100644
index 0000000..e43abc8
--- /dev/null
+++ b/drivers/misc/vexpress/sysreg.c
@@ -0,0 +1,423 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/leds.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/stat.h>
+#include <linux/timer.h>
+#include <linux/vexpress.h>
+
+#define SYS_ID 0x000
+#define SYS_SW 0x004
+#define SYS_LED 0x008
+#define SYS_100HZ 0x024
+#define SYS_FLAGS 0x030
+#define SYS_FLAGSSET 0x030
+#define SYS_FLAGSCLR 0x034
+#define SYS_NVFLAGS 0x038
+#define SYS_NVFLAGSSET 0x038
+#define SYS_NVFLAGSCLR 0x03c
+#define SYS_MCI 0x048
+#define SYS_FLASH 0x04c
+#define SYS_CFGSW 0x058
+#define SYS_24MHZ 0x05c
+#define SYS_MISC 0x060
+#define SYS_DMA 0x064
+#define SYS_PROCID0 0x084
+#define SYS_PROCID1 0x088
+#define SYS_CFGDATA 0x0a0
+#define SYS_CFGCTRL 0x0a4
+#define SYS_CFGSTAT 0x0a8
+
+#define SYS_HBI_MASK 0xfff
+#define SYS_ID_HBI_SHIFT 16
+#define SYS_PROCIDx_HBI_SHIFT 0
+
+#define SYS_MCI_CARDIN (1 << 0)
+#define SYS_MCI_WPROT (1 << 1)
+
+#define SYS_FLASH_WPn (1 << 0)
+
+#define SYS_MISC_MASTERSITE (1 << 14)
+
+#define SYS_CFGCTRL_START (1 << 31)
+#define SYS_CFGCTRL_WRITE (1 << 30)
+#define SYS_CFGCTRL_DCC(n) (((n) & 0xf) << 26)
+#define SYS_CFGCTRL_FUNC(n) (((n) & 0x3f) << 20)
+#define SYS_CFGCTRL_SITE(n) (((n) & 0x3) << 16)
+#define SYS_CFGCTRL_POSITION(n) (((n) & 0xf) << 12)
+#define SYS_CFGCTRL_DEVICE(n) (((n) & 0xfff) << 0)
+
+#define SYS_CFGSTAT_ERR (1 << 1)
+#define SYS_CFGSTAT_COMPLETE (1 << 0)
+
+
+static void __iomem *vexpress_sysreg_base;
+static struct device *vexpress_sysreg_dev;
+static int vexpress_master_site;
+
+
+void __init vexpress_flags_set(u32 data)
+{
+ writel(~0, vexpress_sysreg_base + SYS_FLAGSCLR);
+ writel(data, vexpress_sysreg_base + SYS_FLAGSSET);
+}
+
+u32 vexpress_get_procid(int site)
+{
+ if (site == VEXPRESS_SITE_MASTER)
+ site = vexpress_master_site;
+
+ return readl(vexpress_sysreg_base + (site == VEXPRESS_SITE_DB1 ?
+ SYS_PROCID0 : SYS_PROCID1));
+}
+
+u32 vexpress_get_hbi(int site)
+{
+ u32 id;
+
+ switch (site) {
+ case VEXPRESS_SITE_MB:
+ id = readl(vexpress_sysreg_base + SYS_ID);
+ return (id >> SYS_ID_HBI_SHIFT) & SYS_HBI_MASK;
+ case VEXPRESS_SITE_MASTER:
+ case VEXPRESS_SITE_DB1:
+ case VEXPRESS_SITE_DB2:
+ id = vexpress_get_procid(site);
+ return (id >> SYS_PROCIDx_HBI_SHIFT) & SYS_HBI_MASK;
+ }
+
+ return ~0;
+}
+
+void __iomem *vexpress_get_24mhz_clock_base(void)
+{
+ return vexpress_sysreg_base + SYS_24MHZ;
+}
+
+
+static struct vexpress_config_bridge *vexpress_sysreg_config_bridge;
+static struct timer_list vexpress_sysreg_config_timer;
+static u32 *vexpress_sysreg_config_data;
+static int vexpress_sysreg_config_tries;
+
+static int vexpress_sysreg_config_command(bool async, bool write,
+ unsigned func, struct vexpress_config_address *addr, u32 *data)
+{
+ int res = 0;
+ u32 command;
+
+ if (WARN_ON(!vexpress_sysreg_base))
+ return -ENOENT;
+
+ command = readl(vexpress_sysreg_base + SYS_CFGCTRL);
+ if (WARN_ON(command & SYS_CFGCTRL_START))
+ return -EBUSY;
+
+ command = SYS_CFGCTRL_START;
+ command |= write ? SYS_CFGCTRL_WRITE : 0;
+ command |= SYS_CFGCTRL_DCC(addr->dcc);
+ command |= SYS_CFGCTRL_FUNC(func);
+ command |= SYS_CFGCTRL_SITE(addr->site);
+ command |= SYS_CFGCTRL_POSITION(addr->position);
+ command |= SYS_CFGCTRL_DEVICE(addr->device);
+
+ if (write)
+ writel(*data, vexpress_sysreg_base + SYS_CFGDATA);
+ else
+ vexpress_sysreg_config_data = data;
+ writel(0, vexpress_sysreg_base + SYS_CFGSTAT);
+ writel(command, vexpress_sysreg_base + SYS_CFGCTRL);
+ mb();
+
+ if (async) {
+ vexpress_sysreg_config_tries = 100;
+ mod_timer(&vexpress_sysreg_config_timer,
+ jiffies + usecs_to_jiffies(100));
+ } else {
+ u32 val;
+
+ do {
+ cpu_relax();
+ val = readl(vexpress_sysreg_base + SYS_CFGSTAT);
+ } while (!val);
+
+ if (!write && (val & SYS_CFGSTAT_COMPLETE))
+ *data = readl(vexpress_sysreg_base + SYS_CFGDATA);
+
+ if (val & SYS_CFGSTAT_ERR)
+ res = -EINVAL;
+ }
+
+ return res;
+}
+
+struct vexpress_config_bridge_info vexpress_sysreg_config_bridge_info = {
+ .name = "vexpress-sysreg",
+ .command = vexpress_sysreg_config_command,
+};
+
+static void vexpress_sysreg_config_complete(unsigned long data)
+{
+ int err = 0;
+ u32 val = readl(vexpress_sysreg_base + SYS_CFGSTAT);
+
+ if (val & SYS_CFGSTAT_ERR)
+ err = -EINVAL;
+ if (!vexpress_sysreg_config_tries--)
+ err = -ETIMEDOUT;
+
+ if (!err && !(val & SYS_CFGSTAT_COMPLETE)) {
+ mod_timer(&vexpress_sysreg_config_timer,
+ jiffies + usecs_to_jiffies(50));
+ return;
+ }
+
+ if (vexpress_sysreg_config_data) {
+ *vexpress_sysreg_config_data = readl(vexpress_sysreg_base +
+ SYS_CFGDATA);
+ vexpress_sysreg_config_data = NULL;
+ }
+
+ vexpress_config_complete(vexpress_sysreg_config_bridge, err);
+}
+
+
+static struct vexpress_sysreg_gpio {
+ unsigned long reg;
+ u32 value;
+} vexpress_sysreg_gpios[] = {
+ [VEXPRESS_GPIO_MMC_CARDIN] = {
+ .reg = SYS_MCI,
+ .value = SYS_MCI_CARDIN,
+ },
+ [VEXPRESS_GPIO_MMC_WPROT] = {
+ .reg = SYS_MCI,
+ .value = SYS_MCI_WPROT,
+ },
+ [VEXPRESS_GPIO_FLASH_WPn] = {
+ .reg = SYS_FLASH,
+ .value = SYS_FLASH_WPn,
+ },
+};
+
+static int vexpress_sysreg_gpio_direction_input(struct gpio_chip *chip,
+ unsigned offset)
+{
+ return 0;
+}
+
+static int vexpress_sysreg_gpio_direction_output(struct gpio_chip *chip,
+ unsigned offset, int value)
+{
+ return 0;
+}
+
+static int vexpress_sysreg_gpio_get(struct gpio_chip *chip,
+ unsigned offset)
+{
+ struct vexpress_sysreg_gpio *gpio = &vexpress_sysreg_gpios[offset];
+ u32 reg_value = readl(vexpress_sysreg_base + gpio->reg);
+
+ return !!(reg_value & gpio->value);
+}
+
+static void vexpress_sysreg_gpio_set(struct gpio_chip *chip,
+ unsigned offset, int value)
+{
+ struct vexpress_sysreg_gpio *gpio = &vexpress_sysreg_gpios[offset];
+ u32 reg_value = readl(vexpress_sysreg_base + gpio->reg);
+
+ if (value)
+ reg_value |= gpio->value;
+ else
+ reg_value &= ~gpio->value;
+
+ writel(reg_value, vexpress_sysreg_base + gpio->reg);
+}
+
+static struct gpio_chip vexpress_sysreg_gpio_chip = {
+ .label = "vexpress-sysreg",
+ .direction_input = vexpress_sysreg_gpio_direction_input,
+ .direction_output = vexpress_sysreg_gpio_direction_output,
+ .get = vexpress_sysreg_gpio_get,
+ .set = vexpress_sysreg_gpio_set,
+ .ngpio = ARRAY_SIZE(vexpress_sysreg_gpios),
+ .base = 0,
+};
+
+
+void __init vexpress_sysreg_early_init(void __iomem *base)
+{
+ if (WARN_ON(!base))
+ return;
+
+ vexpress_sysreg_base = base;
+
+ if (readl(vexpress_sysreg_base + SYS_MISC) & SYS_MISC_MASTERSITE)
+ vexpress_master_site = VEXPRESS_SITE_DB2;
+ else
+ vexpress_master_site = VEXPRESS_SITE_DB1;
+
+ vexpress_config_set_master_site(vexpress_master_site);
+
+ vexpress_sysreg_config_bridge = vexpress_config_bridge_register(
+ &vexpress_sysreg_config_bridge_info);
+}
+
+void __init vexpress_sysreg_of_early_init(void)
+{
+ struct device_node *node = of_find_compatible_node(NULL, NULL,
+ "arm,vexpress-sysreg");
+
+ vexpress_sysreg_early_init(of_iomap(node, 0));
+}
+
+
+static ssize_t vexpress_sysreg_sys_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0x%08x\n", readl(vexpress_sysreg_base + SYS_ID));
+}
+
+DEVICE_ATTR(sys_id, S_IRUGO, vexpress_sysreg_sys_id_show, NULL);
+
+static int __devinit vexpress_sysreg_probe(struct platform_device *pdev)
+{
+ int err;
+ struct resource *res = platform_get_resource(pdev,
+ IORESOURCE_MEM, 0);
+
+ if (!devm_request_mem_region(&pdev->dev, res->start,
+ resource_size(res), pdev->name)) {
+ dev_err(&pdev->dev, "Failed to request memory region!\n");
+ return -EBUSY;
+ }
+
+ if (!vexpress_sysreg_base)
+ vexpress_sysreg_base = devm_ioremap(&pdev->dev, res->start,
+ resource_size(res));
+
+ if (!vexpress_sysreg_base) {
+ dev_err(&pdev->dev, "Failed to obtain base address!\n");
+ return -EFAULT;
+ }
+
+ setup_timer(&vexpress_sysreg_config_timer,
+ vexpress_sysreg_config_complete, 0);
+
+ vexpress_sysreg_gpio_chip.dev = &pdev->dev;
+ err = gpiochip_add(&vexpress_sysreg_gpio_chip);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to register GPIO chip! (%d)\n",
+ err);
+ return err;
+ }
+
+ vexpress_sysreg_dev = &pdev->dev;
+
+ device_create_file(vexpress_sysreg_dev, &dev_attr_sys_id);
+
+ return 0;
+}
+
+static const struct of_device_id vexpress_sysreg_match[] = {
+ { .compatible = "arm,vexpress-sysreg", },
+ {},
+};
+
+static struct platform_driver vexpress_sysreg_driver = {
+ .driver = {
+ .name = "vexpress-sysreg",
+ .of_match_table = vexpress_sysreg_match,
+ },
+ .probe = vexpress_sysreg_probe,
+};
+
+static int __init vexpress_sysreg_init(void)
+{
+ return platform_driver_register(&vexpress_sysreg_driver);
+}
+subsys_initcall(vexpress_sysreg_init);
+
+
+struct vexpress_sysreg_led {
+ u32 mask;
+ struct led_classdev cdev;
+} vexpress_sysreg_leds[] = {
+ { .mask = 1 << 0, .cdev.name = "v2m:green:user1",
+ .cdev.default_trigger = "heartbeat", },
+ { .mask = 1 << 1, .cdev.name = "v2m:green:user2",
+ .cdev.default_trigger = "mmc0", },
+ { .mask = 1 << 2, .cdev.name = "v2m:green:user3", },
+ { .mask = 1 << 3, .cdev.name = "v2m:green:user4", },
+ { .mask = 1 << 4, .cdev.name = "v2m:green:user5", },
+ { .mask = 1 << 5, .cdev.name = "v2m:green:user6", },
+ { .mask = 1 << 6, .cdev.name = "v2m:green:user7", },
+ { .mask = 1 << 7, .cdev.name = "v2m:green:user8", },
+};
+
+static DEFINE_SPINLOCK(vexpress_sysreg_leds_lock);
+
+static void vexpress_sysreg_led_brightness_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct vexpress_sysreg_led *led = container_of(cdev,
+ struct vexpress_sysreg_led, cdev);
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&vexpress_sysreg_leds_lock, flags);
+
+ val = readl(vexpress_sysreg_base + SYS_LED);
+ if (brightness == LED_OFF)
+ val &= ~led->mask;
+ else
+ val |= led->mask;
+ writel(val, vexpress_sysreg_base + SYS_LED);
+
+ spin_unlock_irqrestore(&vexpress_sysreg_leds_lock, flags);
+}
+
+static int __init vexpress_sysreg_init_leds(void)
+{
+ struct vexpress_sysreg_led *led;
+ int i;
+
+ /* Clear all user LEDs */
+ writel(0, vexpress_sysreg_base + SYS_LED);
+
+ for (i = 0, led = vexpress_sysreg_leds;
+ i < ARRAY_SIZE(vexpress_sysreg_leds); i++, led++) {
+ int err;
+
+ led->cdev.brightness_set = vexpress_sysreg_led_brightness_set;
+ err = led_classdev_register(vexpress_sysreg_dev, &led->cdev);
+ if (err) {
+ dev_err(vexpress_sysreg_dev,
+ "Failed to register LED %d! (%d)\n",
+ i, err);
+ while (led--, i--)
+ led_classdev_unregister(&led->cdev);
+ return err;
+ }
+ }
+
+ return 0;
+}
+device_initcall(vexpress_sysreg_init_leds);
diff --git a/include/linux/vexpress.h b/include/linux/vexpress.h
index 18f03d1..c44d2dc 100644
--- a/include/linux/vexpress.h
+++ b/include/linux/vexpress.h
@@ -134,4 +134,17 @@ int vexpress_osc_driver_register(void);
void vexpress_clk_init(void __iomem *sp810_base);
void vexpress_clk_of_init(void);
+/* System facilities */
+void vexpress_sysreg_early_init(void __iomem *base);
+void vexpress_sysreg_of_early_init(void);
+u32 vexpress_get_procid(int site);
+u32 vexpress_get_hbi(int site);
+void *vexpress_get_24mhz_clock_base(void);
+void __init vexpress_flags_set(u32 data);
+
+/* System pseudo-GPIOs */
+#define VEXPRESS_GPIO_MMC_CARDIN 0
+#define VEXPRESS_GPIO_MMC_WPROT 1
+#define VEXPRESS_GPIO_FLASH_WPn 2
+
#endif
--
1.7.9.5
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