nvmem: resolve cells from DT at registration time

Currently we're creating a new cell structure everytime a DT user
calls nvmem_cell_get().

Change this behavior by resolving the cells during nvmem provider
registration and adding all cells to the provider's list. Make
of_nvmem_cell_get() just parse the phandle and look the cell up
in the relevant provider's list.

Don't drop the cell in nvmem_cell_put().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 8e01088..74b6b97 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -456,6 +456,73 @@ out:
        return rval;
 }
 
+static struct nvmem_cell *
+nvmem_find_cell_by_index(struct nvmem_device *nvmem, int index)
+{
+       struct nvmem_cell *cell = NULL;
+       int i = 0;
+
+       mutex_lock(&nvmem_mutex);
+       list_for_each_entry(cell, &nvmem->cells, node) {
+               if (index == i++)
+                       break;
+       }
+       mutex_unlock(&nvmem_mutex);
+
+       return cell;
+}
+
+static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
+{
+       struct device_node *parent, *child;
+       struct device *dev = &nvmem->dev;
+       struct nvmem_cell *cell;
+       const __be32 *addr;
+       int len;
+
+       parent = dev->of_node;
+
+       for_each_child_of_node(parent, child) {
+               addr = of_get_property(child, "reg", &len);
+               if (!addr || (len < 2 * sizeof(u32))) {
+                       dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
+                       return -EINVAL;
+               }
+
+               cell = kzalloc(sizeof(*cell), GFP_KERNEL);
+               if (!cell)
+                       return -ENOMEM;
+
+               cell->nvmem = nvmem;
+               cell->offset = be32_to_cpup(addr++);
+               cell->bytes = be32_to_cpup(addr);
+               cell->name = child->name;
+
+               addr = of_get_property(child, "bits", &len);
+               if (addr && len == (2 * sizeof(u32))) {
+                       cell->bit_offset = be32_to_cpup(addr++);
+                       cell->nbits = be32_to_cpup(addr);
+               }
+
+               if (cell->nbits)
+                       cell->bytes = DIV_ROUND_UP(
+                                       cell->nbits + cell->bit_offset,
+                                       BITS_PER_BYTE);
+
+               if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
+                       dev_err(dev, "cell %s unaligned to nvmem stride %d\n",
+                               cell->name, nvmem->stride);
+                       /* Cells already added will be freed later. */
+                       kfree(cell);
+                       return -EINVAL;
+               }
+
+               nvmem_cell_add(cell);
+       }
+
+       return 0;
+}
+
 /**
  * nvmem_register() - Register a nvmem device for given nvmem_config.
  * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
@@ -546,6 +613,10 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
        if (rval)
                goto err_remove_cells;
 
+       rval = nvmem_add_cells_from_of(nvmem);
+       if (rval)
+               goto err_remove_cells;
+
        return nvmem;
 
 err_remove_cells:
@@ -848,10 +919,8 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
                                            const char *name)
 {
        struct device_node *cell_np, *nvmem_np;
-       struct nvmem_cell *cell;
        struct nvmem_device *nvmem;
-       const __be32 *addr;
-       int rval, len;
+       struct nvmem_cell *cell;
        int index = 0;
 
        /* if cell name exists, find index to the name */
@@ -871,54 +940,13 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
        if (IS_ERR(nvmem))
                return ERR_CAST(nvmem);
 
-       addr = of_get_property(cell_np, "reg", &len);
-       if (!addr || (len < 2 * sizeof(u32))) {
-               dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n",
-                       cell_np);
-               rval  = -EINVAL;
-               goto err_mem;
-       }
-
-       cell = kzalloc(sizeof(*cell), GFP_KERNEL);
+       cell = nvmem_find_cell_by_index(nvmem, index);
        if (!cell) {
-               rval = -ENOMEM;
-               goto err_mem;
-       }
-
-       cell->nvmem = nvmem;
-       cell->offset = be32_to_cpup(addr++);
-       cell->bytes = be32_to_cpup(addr);
-       cell->name = cell_np->name;
-
-       addr = of_get_property(cell_np, "bits", &len);
-       if (addr && len == (2 * sizeof(u32))) {
-               cell->bit_offset = be32_to_cpup(addr++);
-               cell->nbits = be32_to_cpup(addr);
-       }
-
-       if (cell->nbits)
-               cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
-                                          BITS_PER_BYTE);
-
-       if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
-                       dev_err(&nvmem->dev,
-                               "cell %s unaligned to nvmem stride %d\n",
-                               cell->name, nvmem->stride);
-               rval  = -EINVAL;
-               goto err_sanity;
+               __nvmem_device_put(nvmem);
+               return ERR_PTR(-ENOENT);
        }
 
-       nvmem_cell_add(cell);
-
        return cell;
-
-err_sanity:
-       kfree(cell);
-
-err_mem:
-       __nvmem_device_put(nvmem);
-
-       return ERR_PTR(rval);
 }
 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
 #endif
@@ -1024,7 +1052,6 @@ void nvmem_cell_put(struct nvmem_cell *cell)
        struct nvmem_device *nvmem = cell->nvmem;
 
        __nvmem_device_put(nvmem);
-       nvmem_cell_drop(cell);
 }
 EXPORT_SYMBOL_GPL(nvmem_cell_put);