@@ -532,8 +532,6 @@ void __init early_init_fdt_scan_reserved_mem(void)
break;
memblock_reserve(base, size);
}
-
- fdt_init_reserved_mem();
}
/**
@@ -1259,6 +1257,9 @@ void __init unflatten_device_tree(void)
of_alias_scan(early_init_dt_alloc_memory_arch);
unittest_unflatten_overlay_base();
+
+ /* initialize the reserved memory regions */
+ fdt_init_reserved_mem();
}
/**
@@ -9,6 +9,7 @@
*/
#define FDT_ALIGN_SIZE 8
+#define MAX_RESERVED_REGIONS 64
/**
* struct alias_prop - Alias property in 'aliases' node
@@ -27,7 +27,6 @@
#include "of_private.h"
-#define MAX_RESERVED_REGIONS 64
static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
static int reserved_mem_count;
@@ -106,7 +105,6 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
phys_addr_t base, size;
int len;
const __be32 *prop;
- int first = 1;
bool nomap;
prop = of_get_flat_dt_prop(node, "reg", &len);
@@ -134,10 +132,6 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
uname, &base, (unsigned long)(size / SZ_1M));
len -= t_len;
- if (first) {
- fdt_reserved_mem_save_node(node, uname, base, size);
- first = 0;
- }
}
return 0;
}
@@ -165,12 +159,69 @@ static int __init __reserved_mem_check_root(unsigned long node)
return 0;
}
+/**
+ * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
+ * reserved memory regions.
+ *
+ * This function is used to scan through the DT and store the
+ * information for the reserved memory regions that are defined using
+ * the "reg" property. The region node number, name, base address, and
+ * size are all stored in the reserved_mem array by calling the
+ * fdt_reserved_mem_save_node() function.
+ */
+static void __init fdt_scan_reserved_mem_reg_nodes(void)
+{
+ int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+ const void *fdt = initial_boot_params;
+ phys_addr_t base, size;
+ const __be32 *prop;
+ int node, child;
+ int len;
+
+ node = fdt_path_offset(fdt, "/reserved-memory");
+ if (node < 0) {
+ pr_info("Reserved memory: No reserved-memory node in the DT\n");
+ return;
+ }
+
+ if (__reserved_mem_check_root(node)) {
+ pr_err("Reserved memory: unsupported node format, ignoring\n");
+ return;
+ }
+
+ fdt_for_each_subnode(child, fdt, node) {
+ const char *uname;
+
+ prop = of_get_flat_dt_prop(child, "reg", &len);
+ if (!prop)
+ continue;
+ if (!of_fdt_device_is_available(fdt, child))
+ continue;
+
+ uname = fdt_get_name(fdt, child, NULL);
+ if (len && len % t_len != 0) {
+ pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
+ uname);
+ continue;
+ }
+ base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+ size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+ if (size)
+ fdt_reserved_mem_save_node(child, uname, base, size);
+ }
+}
+
+static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
+
/*
* fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
*/
int __init fdt_scan_reserved_mem(void)
{
int node, child;
+ int dynamic_nodes_cnt = 0;
+ int dynamic_nodes[MAX_RESERVED_REGIONS];
const void *fdt = initial_boot_params;
node = fdt_path_offset(fdt, "/reserved-memory");
@@ -192,8 +243,24 @@ int __init fdt_scan_reserved_mem(void)
uname = fdt_get_name(fdt, child, NULL);
err = __reserved_mem_reserve_reg(child, uname);
- if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
- fdt_reserved_mem_save_node(child, uname, 0, 0);
+ /*
+ * Save the nodes for the dynamically-placed regions
+ * into an array which will be used for allocation right
+ * after all the statically-placed regions are reserved
+ * or marked as no-map. This is done to avoid dynamically
+ * allocating from one of the statically-placed regions.
+ */
+ if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
+ dynamic_nodes[dynamic_nodes_cnt] = child;
+ dynamic_nodes_cnt++;
+ }
+ }
+ for (int i = 0; i < dynamic_nodes_cnt; i++) {
+ const char *uname;
+
+ child = dynamic_nodes[i];
+ uname = fdt_get_name(fdt, child, NULL);
+ __reserved_mem_alloc_size(child, uname);
}
return 0;
}
@@ -253,8 +320,7 @@ static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
* __reserved_mem_alloc_size() - allocate reserved memory described by
* 'size', 'alignment' and 'alloc-ranges' properties.
*/
-static int __init __reserved_mem_alloc_size(unsigned long node,
- const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
+static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
{
int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
phys_addr_t start = 0, end = 0;
@@ -333,10 +399,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
uname, (unsigned long)(size / SZ_1M));
return -ENOMEM;
}
-
- *res_base = base;
- *res_size = size;
-
+ fdt_reserved_mem_save_node(node, uname, base, size);
return 0;
}
@@ -431,6 +494,8 @@ void __init fdt_init_reserved_mem(void)
{
int i;
+ fdt_scan_reserved_mem_reg_nodes();
+
/* check for overlapping reserved regions */
__rmem_check_for_overlap();
@@ -449,30 +514,23 @@ void __init fdt_init_reserved_mem(void)
if (prop)
rmem->phandle = of_read_number(prop, len/4);
- if (rmem->size == 0)
- err = __reserved_mem_alloc_size(node, rmem->name,
- &rmem->base, &rmem->size);
- if (err == 0) {
- err = __reserved_mem_init_node(rmem);
- if (err != 0 && err != -ENOENT) {
- pr_info("node %s compatible matching fail\n",
- rmem->name);
- if (nomap)
- memblock_clear_nomap(rmem->base, rmem->size);
- else
- memblock_phys_free(rmem->base,
- rmem->size);
- } else {
- phys_addr_t end = rmem->base + rmem->size - 1;
- bool reusable =
- (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
-
- pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
- &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
- nomap ? "nomap" : "map",
- reusable ? "reusable" : "non-reusable",
- rmem->name ? rmem->name : "unknown");
- }
+ err = __reserved_mem_init_node(rmem);
+ if (err != 0 && err != -ENOENT) {
+ pr_info("node %s compatible matching fail\n", rmem->name);
+ if (nomap)
+ memblock_clear_nomap(rmem->base, rmem->size);
+ else
+ memblock_phys_free(rmem->base, rmem->size);
+ } else {
+ phys_addr_t end = rmem->base + rmem->size - 1;
+ bool reusable =
+ (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
+
+ pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
+ &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
+ nomap ? "nomap" : "map",
+ reusable ? "reusable" : "non-reusable",
+ rmem->name ? rmem->name : "unknown");
}
}
}
The current implementation processes the reserved memory regions in two stages which are done with two separate functions within the early_init_fdt_scan_reserved_mem() function. Within the two stages of processing, the reserved memory regions are broken up into two groups which are processed differently: i) Statically-placed reserved memory regions i.e. regions defined with a static start address and size using the "reg" property in the DT. ii) Dynamically-placed reserved memory regions. i.e. regions defined by specifying a range of addresses where they can be placed in memory using the "alloc_ranges" and "size" properties in the DT. Stage 1: fdt_scan_reserved_mem() This stage of the reserved memory processing is used to scan through the reserved memory nodes defined in the devicetree and do the following on each of the nodes: 1) If the node represents a statically-placed reserved memory region, i.e. it is defined using the "reg" property: - Call memblock_reserve() or memblock_mark_nomap() as needed. - Add the information for the reserved region to the reserved_mem array. eg: fdt_reserved_mem_save_node(node, name, base, size); 2) If the node represents a dynamically-placed reserved memory region, i.e. it is defined using "alloc-ranges" and "size" properties: - Add the information for the region to the reserved_mem array with the starting address and size set to 0. eg: fdt_reserved_mem_save_node(node, name, 0, 0); Stage 2: fdt_init_reserved_mem() This stage of the reserved memory processing is used to iterate through the reserved_mem array which was populated in stage 1 and do the following on each of the entries: 1) If the entry represents a statically-placed reserved memory region: - Call the region specific init function. 2) If the entry represents a dynamically-placed reserved memory region: - Call __reserved_mem_alloc_size() which is used to allocate memory for the region using memblock_phys_alloc_range(), and call memblock_mark_nomap() on the allocated region if the region is specified as a no-map region. - Call the region specific init function. On architectures such as arm64, the dynamic allocation of the reserved_mem array needs to be done after the page tables have been setup because memblock allocated memory is not writable until then. This means that the reserved_mem array will not be available to store any reserved memory information until after the page tables have been setup. It is possible to call memblock_reserve() and memblock_mark_nomap() on the statically-placed reserved memory regions and not need to save them to the reserved_mem array until later. This is because all the information we need is present in the devicetree. Dynamically-placed reserved memory regions on the other hand get assigned a start address only at runtime, and since memblock_reserve() and memblock_mark_nomap() need to be called before the memory mappings are created, the allocation needs to happen before the page tables are setup. To make it easier to handle dynamically-placed reserved memory regions before the page tables are setup, this patch makes changes to the steps above to process the reserved memory regions in the following ways: Step 1: fdt_scan_reserved_mem() This stage of the reserved memory processing is used to scan through the reserved memory nodes defined in the devicetree and do the following on each of the nodes: 1) If the node represents a statically-placed reserved memory region, i.e. it is defined using the "reg" property: - Call memblock_reserve() or memblock_mark_nomap() as needed. 2) If the node represents a dynamically-placed reserved memory region, i.e. it is defined using "alloc-ranges" and "size" properties: - Call __reserved_mem_alloc_size() which will: i) Allocate memory for the reserved memory region. ii) Call memblock_mark_nomap() as needed. Note: There is no need to explicitly call memblock_reserve() here because it is already called by memblock when the memory for the region is being allocated. iii) Save the information for the region in the reserved_mem array. Step 2: fdt_init_reserved_mem() This stage of the reserved memory processing is used to: 1) Add the information for the statically-placed reserved memory into the reserved_mem array. 2) Iterate through all the entries in the array and call the region specific init function for each of them. fdt_init_reserved_mem() is also now called from within the unflatten_device_tree() function so that this step happens after the page tables have been setup. Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com> --- drivers/of/fdt.c | 5 +- drivers/of/of_private.h | 1 + drivers/of/of_reserved_mem.c | 134 +++++++++++++++++++++++++---------- 3 files changed, 100 insertions(+), 40 deletions(-)