From 02464e386bb5f0a022c121f95ae75cf583759d95 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Thu, 6 Aug 2015 15:31:02 -0600 Subject: fdt: add new fdt address parsing functions fdtdec_get_addr_size() hard-codes the number of cells used to represent an address or size in DT. This is incorrect in many cases depending on the DT binding for a particular node or property (e.g. it is incorrect for the "reg" property). In most cases, DT parsing code must use the properties #address-cells and #size-cells to parse addres properties. This change splits up the implementation of fdtdec_get_addr_size() so that the core logic can be used for both hard-coded and non-hard-coded cases. Various wrapper functions are implemented that support cases where hard-coded cell counts should or should not be used, and where the client does and doesn't know the parent node ID that contains the properties #address-cells and #size-cells. dev_get_addr() is updated to use the new functions. Core functionality in fdtdec_get_addr_size_fixed() is widely tested via fdtdec_get_addr_size(). I tested fdtdec_get_addr_size_auto_noparent() and dev_get_addr() by manually modifying the Tegra I2C driver to invoke them. Much of the core implementation of fdtdec_get_addr_size_fixed(), fdtdec_get_addr_size_auto_parent(), and fdtdec_get_addr_size_auto_noparent() comes from Thierry Reding's previous commit "fdt: Fix fdtdec_get_addr_size() for 64-bit". Based-on-work-by: Thierry Reding Cc: Thierry Reding Cc: Simon Glass Cc: Michal Suchanek Signed-off-by: Stephen Warren Acked-by: Simon Glass Dropped #define DEBUG at the top of fdtdec.c: Signed-off-by: Simon Glass --- include/fdtdec.h | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 103 insertions(+), 8 deletions(-) (limited to 'include') diff --git a/include/fdtdec.h b/include/fdtdec.h index a422ecedb8..2de6dda04c 100644 --- a/include/fdtdec.h +++ b/include/fdtdec.h @@ -295,10 +295,90 @@ int fdtdec_next_compatible(const void *blob, int node, int fdtdec_next_compatible_subnode(const void *blob, int node, enum fdt_compat_id id, int *depthp); -/** - * Look up an address property in a node and return it as an address. - * The property must hold either one address with no trailing data or - * one address with a length. This is only tested on 32-bit machines. +/* + * Look up an address property in a node and return the parsed address, and + * optionally the parsed size. + * + * This variant assumes a known and fixed number of cells are used to + * represent the address and size. + * + * You probably don't want to use this function directly except to parse + * non-standard properties, and never to parse the "reg" property. Instead, + * use one of the "auto" variants below, which automatically honor the + * #address-cells and #size-cells properties in the parent node. + * + * @param blob FDT blob + * @param node node to examine + * @param prop_name name of property to find + * @param index which address to retrieve from a list of addresses. Often 0. + * @param na the number of cells used to represent an address + * @param ns the number of cells used to represent a size + * @param sizep a pointer to store the size into. Use NULL if not required + * @return address, if found, or FDT_ADDR_T_NONE if not + */ +fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node, + const char *prop_name, int index, int na, int ns, + fdt_size_t *sizep); + +/* + * Look up an address property in a node and return the parsed address, and + * optionally the parsed size. + * + * This variant automatically determines the number of cells used to represent + * the address and size by parsing the provided parent node's #address-cells + * and #size-cells properties. + * + * @param blob FDT blob + * @param parent parent node of @node + * @param node node to examine + * @param prop_name name of property to find + * @param index which address to retrieve from a list of addresses. Often 0. + * @param sizep a pointer to store the size into. Use NULL if not required + * @return address, if found, or FDT_ADDR_T_NONE if not + */ +fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent, + int node, const char *prop_name, int index, fdt_size_t *sizep); + +/* + * Look up an address property in a node and return the parsed address, and + * optionally the parsed size. + * + * This variant automatically determines the number of cells used to represent + * the address and size by parsing the parent node's #address-cells + * and #size-cells properties. The parent node is automatically found. + * + * The automatic parent lookup implemented by this function is slow. + * Consequently, fdtdec_get_addr_size_auto_parent() should be used where + * possible. + * + * @param blob FDT blob + * @param parent parent node of @node + * @param node node to examine + * @param prop_name name of property to find + * @param index which address to retrieve from a list of addresses. Often 0. + * @param sizep a pointer to store the size into. Use NULL if not required + * @return address, if found, or FDT_ADDR_T_NONE if not + */ +fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node, + const char *prop_name, int index, fdt_size_t *sizep); + +/* + * Look up an address property in a node and return the parsed address. + * + * This variant hard-codes the number of cells used to represent the address + * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also + * always returns the first address value in the property (index 0). + * + * Use of this function is not recommended due to the hard-coding of cell + * counts. There is no programmatic validation that these hard-coded values + * actually match the device tree content in any way at all. This assumption + * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately + * set in the U-Boot build and exercising strict control over DT content to + * ensure use of matching #address-cells/#size-cells properties. However, this + * approach is error-prone; those familiar with DT will not expect the + * assumption to exist, and could easily invalidate it. If the assumption is + * invalidated, this function will not report the issue, and debugging will + * be required. Instead, use fdtdec_get_addr_size_auto_parent(). * * @param blob FDT blob * @param node node to examine @@ -308,14 +388,29 @@ int fdtdec_next_compatible_subnode(const void *blob, int node, fdt_addr_t fdtdec_get_addr(const void *blob, int node, const char *prop_name); -/** - * Look up an address property in a node and return it as an address. - * The property must hold one address with a length. This is only tested - * on 32-bit machines. +/* + * Look up an address property in a node and return the parsed address, and + * optionally the parsed size. + * + * This variant hard-codes the number of cells used to represent the address + * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also + * always returns the first address value in the property (index 0). + * + * Use of this function is not recommended due to the hard-coding of cell + * counts. There is no programmatic validation that these hard-coded values + * actually match the device tree content in any way at all. This assumption + * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately + * set in the U-Boot build and exercising strict control over DT content to + * ensure use of matching #address-cells/#size-cells properties. However, this + * approach is error-prone; those familiar with DT will not expect the + * assumption to exist, and could easily invalidate it. If the assumption is + * invalidated, this function will not report the issue, and debugging will + * be required. Instead, use fdtdec_get_addr_size_auto_parent(). * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find + * @param sizep a pointer to store the size into. Use NULL if not required * @return address, if found, or FDT_ADDR_T_NONE if not */ fdt_addr_t fdtdec_get_addr_size(const void *blob, int node, -- cgit v1.2.1