From: Dmitry Shmidt <[email protected]> Allow pre-defined overlay_mgr DT fragments to be enabled on the fly by writing to: /sys/devices/platform/overlay_mgr/current_overlay
Cc: Rob Herring <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Frank Rowand <[email protected]> Cc: Dmitry Shmidt <[email protected]> Cc: [email protected] Signed-off-by: Dmitry Shmidt <[email protected]> [jstultz: Slightly reworded commit message] Signed-off-by: John Stultz <[email protected]> --- drivers/of/overlay_mgr.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/drivers/of/overlay_mgr.c b/drivers/of/overlay_mgr.c index 1fdeb0a..5a082be 100644 --- a/drivers/of/overlay_mgr.c +++ b/drivers/of/overlay_mgr.c @@ -18,10 +18,14 @@ #include <linux/kernel.h> #include <linux/of.h> #include <linux/platform_device.h> +#include <linux/slab.h> static char *of_overlay_dt_entry; module_param_named(overlay_dt_entry, of_overlay_dt_entry, charp, 0644); +static char *of_overlay_dt_apply; +DEFINE_MUTEX(of_overlay_mgr_mutex); + static int of_overlay_mgr_apply_overlay(struct device_node *onp) { int ret; @@ -61,8 +65,56 @@ static int of_overlay_mgr_apply_dt(struct device *dev, char *dt_entry) return 0; } +static ssize_t current_overlay_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + size_t len; + + mutex_lock(&of_overlay_mgr_mutex); + if (!of_overlay_dt_apply) { + mutex_unlock(&of_overlay_mgr_mutex); + return 0; + } + len = strlen(of_overlay_dt_apply); + if (len >= PAGE_SIZE) + len = PAGE_SIZE - 1; + memcpy(buf, of_overlay_dt_apply, len + 1); + mutex_unlock(&of_overlay_mgr_mutex); + return len; +} + +static ssize_t current_overlay_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + mutex_lock(&of_overlay_mgr_mutex); + kfree(of_overlay_dt_apply); + of_overlay_dt_apply = kmalloc(size, GFP_KERNEL); + if (!of_overlay_dt_apply) { + pr_err("overlay_mgr: fail to allocate memory\n"); + mutex_unlock(&of_overlay_mgr_mutex); + return 0; + } + memcpy(of_overlay_dt_apply, buf, size); + of_overlay_dt_apply[size - 1] = '\0'; + + if (of_overlay_mgr_apply_dt(dev, of_overlay_dt_apply)) { + kfree(of_overlay_dt_apply); + of_overlay_dt_apply = NULL; + size = 0; + } + mutex_unlock(&of_overlay_mgr_mutex); + return size; +} + +static DEVICE_ATTR(current_overlay, 0644, current_overlay_show, + current_overlay_store); + static int of_overlay_mgr_probe(struct platform_device *pdev) { + if (device_create_file(&pdev->dev, &dev_attr_current_overlay)) + pr_err("overlay_mgr: fail to register apply entry\n"); + if (!of_overlay_dt_entry) return 0; of_overlay_mgr_apply_dt(&pdev->dev, of_overlay_dt_entry); -- 2.7.4
