[PATCH v2 0/3] doc: global data pointer

Add the description of the global data pointer to the generated HTML documentation.
The first patch converts the GD_FLG_* constants to an enum. The second adds move Sphinx comments. The third finally provides the HTML documentation.
v2: enum gd_flags must not be exposed to assembler code. This avoids a build failure on x86.
Heinrich Schuchardt (3): global_data.h: convert GD_FLG_* to enum global_data.h: add Sphinx documentation doc: global data pointer
doc/develop/global_data.rst | 53 ++++ doc/develop/index.rst | 1 + include/asm-generic/global_data.h | 460 +++++++++++++++++++++++++----- 3 files changed, 446 insertions(+), 68 deletions(-) create mode 100644 doc/develop/global_data.rst
-- 2.28.0

Sphinx documentation is only available for enums not for #defines. Anyway it is better to keep related definitions in an enum.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- v2: enum gd_flags must not be exposed to assembler code --- include/asm-generic/global_data.h | 106 +++++++++++++++++++++++------- 1 file changed, 84 insertions(+), 22 deletions(-)
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h index d4a4e2215d..e4a68e0d91 100644 --- a/include/asm-generic/global_data.h +++ b/include/asm-generic/global_data.h @@ -138,7 +138,6 @@ typedef struct global_data { struct udevice *watchdog_dev; #endif } gd_t; -#endif
#ifdef CONFIG_BOARD_TYPES #define gd_board_type() gd->board_type @@ -146,27 +145,90 @@ typedef struct global_data { #define gd_board_type() 0 #endif
-/* - * Global Data Flags +/** + * enum gd_flags - global data flags + * + * See field flags of &struct global_data. */ -#define GD_FLG_RELOC 0x00001 /* Code was relocated to RAM */ -#define GD_FLG_DEVINIT 0x00002 /* Devices have been initialized */ -#define GD_FLG_SILENT 0x00004 /* Silent mode */ -#define GD_FLG_POSTFAIL 0x00008 /* Critical POST test failed */ -#define GD_FLG_POSTSTOP 0x00010 /* POST seqeunce aborted */ -#define GD_FLG_LOGINIT 0x00020 /* Log Buffer has been initialized */ -#define GD_FLG_DISABLE_CONSOLE 0x00040 /* Disable console (in & out) */ -#define GD_FLG_ENV_READY 0x00080 /* Env. imported into hash table */ -#define GD_FLG_SERIAL_READY 0x00100 /* Pre-reloc serial console ready */ -#define GD_FLG_FULL_MALLOC_INIT 0x00200 /* Full malloc() is ready */ -#define GD_FLG_SPL_INIT 0x00400 /* spl_init() has been called */ -#define GD_FLG_SKIP_RELOC 0x00800 /* Don't relocate */ -#define GD_FLG_RECORD 0x01000 /* Record console */ -#define GD_FLG_ENV_DEFAULT 0x02000 /* Default variable flag */ -#define GD_FLG_SPL_EARLY_INIT 0x04000 /* Early SPL init is done */ -#define GD_FLG_LOG_READY 0x08000 /* Log system is ready for use */ -#define GD_FLG_WDT_READY 0x10000 /* Watchdog is ready for use */ -#define GD_FLG_SKIP_LL_INIT 0x20000 /* Don't perform low-level init */ -#define GD_FLG_SMP_READY 0x40000 /* SMP init is complete */ +enum gd_flags { + /** + * @GD_FLG_RELOC: code was relocated to RAM + */ + GD_FLG_RELOC = 0x00001, + /** + * @GD_FLG_DEVINIT: devices have been initialized + */ + GD_FLG_DEVINIT = 0x00002, + /** + * @GD_FLG_SILENT: silent mode + */ + GD_FLG_SILENT = 0x00004, + /** + * @GD_FLG_POSTFAIL: critical POST test failed + */ + GD_FLG_POSTFAIL = 0x00008, + /** + * @GD_FLG_POSTSTOP: POST sequence aborted + */ + GD_FLG_POSTSTOP = 0x00010, + /** + * @GD_FLG_LOGINIT: log Buffer has been initialized + */ + GD_FLG_LOGINIT = 0x00020, + /** + * @GD_FLG_DISABLE_CONSOLE: disable console (in & out) + */ + GD_FLG_DISABLE_CONSOLE = 0x00040, + /** + * @GD_FLG_ENV_READY: environment imported into hash table + */ + GD_FLG_ENV_READY = 0x00080, + /** + * @GD_FLG_SERIAL_READY: pre-relocation serial console ready + */ + GD_FLG_SERIAL_READY = 0x00100, + /** + * @GD_FLG_FULL_MALLOC_INIT: full malloc() is ready + */ + GD_FLG_FULL_MALLOC_INIT = 0x00200, + /** + * @GD_FLG_SPL_INIT: spl_init() has been called + */ + GD_FLG_SPL_INIT = 0x00400, + /** + * @GD_FLG_SKIP_RELOC: don't relocate + */ + GD_FLG_SKIP_RELOC = 0x00800, + /** + * @GD_FLG_RECORD: record console + */ + GD_FLG_RECORD = 0x01000, + /** + * @GD_FLG_ENV_DEFAULT: default variable flag + */ + GD_FLG_ENV_DEFAULT = 0x02000, + /** + * @GD_FLG_SPL_EARLY_INIT: early SPL initialization is done + */ + GD_FLG_SPL_EARLY_INIT = 0x04000, + /** + * @GD_FLG_LOG_READY: log system is ready for use + */ + GD_FLG_LOG_READY = 0x08000, + /** + * @GD_FLG_WDT_READY: watchdog is ready for use + */ + GD_FLG_WDT_READY = 0x10000, + /** + * @GD_FLG_SKIP_LL_INIT: don't perform low-level initialization + */ + GD_FLG_SKIP_LL_INIT = 0x20000, + /** + * @GD_FLG_SMP_READY: SMP initialization is complete + */ + GD_FLG_SMP_READY = 0x40000, +}; + +#endif /* __ASSEMBLY__ */
#endif /* __ASM_GENERIC_GBL_DATA_H */ -- 2.28.0

On Sun, 20 Sep 2020 at 02:04, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
Sphinx documentation is only available for enums not for #defines. Anyway it is better to keep related definitions in an enum.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de
v2: enum gd_flags must not be exposed to assembler code
include/asm-generic/global_data.h | 106 +++++++++++++++++++++++------- 1 file changed, 84 insertions(+), 22 deletions(-)
Reviewed-by: Simon Glass sjg@chromium.org

Add the missing Sphinx documentation for struct global_data and gd_board_type().
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- v2: no change --- include/asm-generic/global_data.h | 354 ++++++++++++++++++++++++++---- 1 file changed, 308 insertions(+), 46 deletions(-)
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h index e4a68e0d91..7222fa1241 100644 --- a/include/asm-generic/global_data.h +++ b/include/asm-generic/global_data.h @@ -24,121 +24,383 @@ #include <membuff.h> #include <linux/list.h>
-typedef struct global_data { +typedef struct global_data gd_t; + +/** + * struct global_data - global data structure + */ +struct global_data { + /** + * @bd: board information + */ struct bd_info *bd; + /** + * @flags: global data flags + * + * See &enum gd_flags + */ unsigned long flags; + /** + * @baudrate: baud rate of the serial interface + */ unsigned int baudrate; - unsigned long cpu_clk; /* CPU clock in Hz! */ + /** + * @cpu_clk: CPU clock rate in Hz + */ + unsigned long cpu_clk; + /** + * @bus_clk: platform clock rate in Hz + */ unsigned long bus_clk; + /** + * @pci_clk: PCI clock rate in Hz + */ /* We cannot bracket this with CONFIG_PCI due to mpc5xxx */ unsigned long pci_clk; + /** + * @mem_clk: memory clock rate in Hz + */ unsigned long mem_clk; #if defined(CONFIG_LCD) || defined(CONFIG_VIDEO) || defined(CONFIG_DM_VIDEO) - unsigned long fb_base; /* Base address of framebuffer mem */ + /** + * @fb_base: base address of frame buffer memory + */ + unsigned long fb_base; #endif #if defined(CONFIG_POST) + /** + * @post_log_word: active POST tests + * + * @post_log_word is a bit mask defining which POST tests are recorded + * (see constants POST_*). + */ unsigned long post_log_word; /* Record POST activities */ - unsigned long post_log_res; /* success of POST test */ - unsigned long post_init_f_time; /* When post_init_f started */ + /** + * @post_log_res: POST results + * + * @post_log_res is a bit mask with the POST results. A bit with value 1 + * indicates successful execution. + */ + unsigned long post_log_res; + /** + * @post_init_f_time: time in ms when post_init_f() started + */ + unsigned long post_init_f_time; #endif #ifdef CONFIG_BOARD_TYPES + /** + * @board_type: board type + * + * If a U-Boot configuration supports multiple board types, the actual + * board type may be stored in this field. + */ unsigned long board_type; #endif + /** + * @have_console: console is available + * + * A value of 1 indicates that serial_init() was called and a console + * is available. + * A value of 0 indicates that console input and output drivers shall + * not be called. + */ unsigned long have_console; /* serial_init() was called */ #if CONFIG_IS_ENABLED(PRE_CONSOLE_BUFFER) + /** + * @precon_buf_idx: pre-console buffer index + * + * @precon_buf_idx indicates the current position of the buffer used to + * collect output before the console becomes available + */ unsigned long precon_buf_idx; /* Pre-Console buffer index */ #endif - unsigned long env_addr; /* Address of Environment struct */ - unsigned long env_valid; /* Environment valid? enum env_valid */ - unsigned long env_has_init; /* Bitmask of boolean of struct env_location offsets */ - int env_load_prio; /* Priority of the loaded environment */ - - unsigned long ram_base; /* Base address of RAM used by U-Boot */ + /** + * @env_addr: address of environment structure + * + * @env_addr contains the address of the structure holding the + * environment variables. + */ + unsigned long env_addr; + /** + * @env_valid: environment is valid + * + * See &enum env_valid + */ + unsigned long env_valid; + /** + * @env_has_init: bit mask indicating environment locations + * + * &enum env_location defines which bit relates to which location + */ + unsigned long env_has_init; + /** + * @env_load_prio: priority of the loaded environment + */ + int env_load_prio; + /** + * @ram_base: base address of RAM used by U-Boot + */ + unsigned long ram_base; + /** + * @ram_top: top address of RAM used by U-Boot + */ unsigned long ram_top; /* Top address of RAM used by U-Boot */ + /** + * @relocaddr: start address of U-Boot in RAM + * + * After relocation this field indicates the address to which U-Boot + * has been relocated. It can be displayed using the bdinfo command. + * Its value is needed to display the source code when debugging with + * GDB using the 'add-symbol-file u-boot <relocaddr>' command. + */ unsigned long relocaddr; /* Start address of U-Boot in RAM */ - phys_size_t ram_size; /* RAM size */ - unsigned long mon_len; /* monitor len */ + /** + * @ram_size: RAM size in bytes + */ + phys_size_t ram_size; + /** + * @mon_len: monitor length in bytes + */ + unsigned long mon_len; + /** + * @irq_sp: IRQ stack pointer + */ unsigned long irq_sp; /* irq stack pointer */ - unsigned long start_addr_sp; /* start_addr_stackpointer */ + /** + * @start_addr_sp: initial stack pointer address + */ + unsigned long start_addr_sp; + /** + * @reloc_off: relocation offset + */ unsigned long reloc_off; + /** + * @new_gd: pointer to relocated global data + */ struct global_data *new_gd; /* relocated global data */
#ifdef CONFIG_DM - struct udevice *dm_root; /* Root instance for Driver Model */ - struct udevice *dm_root_f; /* Pre-relocation root instance */ - struct list_head uclass_root; /* Head of core tree */ + /** + * @dm_root: root instance for Driver Model + */ + struct udevice *dm_root; + /** + * @dm_root_f: pre-relocation root instance + */ + struct udevice *dm_root_f; + /** + * @uclass_root: head of core tree + */ + struct list_head uclass_root; #endif #ifdef CONFIG_TIMER - struct udevice *timer; /* Timer instance for Driver Model */ + /** + * @timer: timer instance for Driver Model + */ + struct udevice *timer; #endif - - const void *fdt_blob; /* Our device tree, NULL if none */ - void *new_fdt; /* Relocated FDT */ - unsigned long fdt_size; /* Space reserved for relocated FDT */ + /** + * @fdt_blob: U-Boot's own device tree, NULL if none + */ + const void *fdt_blob; + /** + * @new_fdt: relocated device tree + */ + void *new_fdt; + /** + * @fdt_size: space reserved for relocated device space + */ + unsigned long fdt_size; #ifdef CONFIG_OF_LIVE + /** + * @of_root: root node of the live tree + */ struct device_node *of_root; #endif
#if CONFIG_IS_ENABLED(MULTI_DTB_FIT) - const void *multi_dtb_fit; /* uncompressed multi-dtb FIT image */ + /** + * @multi_dtb_fit: pointer to uncompressed multi-dtb FIT image + */ + const void *multi_dtb_fit; #endif - struct jt_funcs *jt; /* jump table */ - char env_buf[32]; /* buffer for env_get() before reloc. */ + /** + * @jt: jump table + * + * The jump table contains pointers to exported functions. A pointer to + * the jump table is passed to standalone applications. + */ + struct jt_funcs *jt; + /** + * @env_buf: buffer for env_get() before reloc + */ + char env_buf[32]; #ifdef CONFIG_TRACE - void *trace_buff; /* The trace buffer */ + /** + * @trace_buff: trace buffer + * + * When tracing function in U-Boot this field points to the buffer + * recording the function calls. + */ + void *trace_buff; #endif #if defined(CONFIG_SYS_I2C) - int cur_i2c_bus; /* current used i2c bus */ + /** + * @cur_i2c_bus: currently used I2C bus + */ + int cur_i2c_bus; #endif + /** + * @timebase_h: high 32 bits of timer + */ unsigned int timebase_h; + /** + * @timebase_l: low 32 bits of timer + */ unsigned int timebase_l; #if CONFIG_VAL(SYS_MALLOC_F_LEN) - unsigned long malloc_base; /* base address of early malloc() */ - unsigned long malloc_limit; /* limit address */ - unsigned long malloc_ptr; /* current address */ + /** + * @malloc_base: base address of early malloc() + */ + unsigned long malloc_base; + /** + * @malloc_limit: limit address of early malloc() + */ + unsigned long malloc_limit; + /** + * @malloc_ptr: current address of early malloc() + */ + unsigned long malloc_ptr; #endif #ifdef CONFIG_PCI - struct pci_controller *hose; /* PCI hose for early use */ - phys_addr_t pci_ram_top; /* top of region accessible to PCI */ + /** + * @hose: PCI hose for early use + */ + struct pci_controller *hose; + /** + * @pci_ram_top: top of region accessible to PCI + */ + phys_addr_t pci_ram_top; #endif #ifdef CONFIG_PCI_BOOTDELAY + /** + * @pcidelay_done: delay time before scanning of PIC hose expired + * + * If CONFIG_PCI_BOOTDELAY=y, pci_hose_scan() waits for the number of + * milliseconds defined by environment variable pcidelay before + * scanning. Once this delay has expired the flag @pcidelay_done + * is set to 1. + */ int pcidelay_done; #endif - struct udevice *cur_serial_dev; /* current serial device */ - struct arch_global_data arch; /* architecture-specific data */ + /** + * @cur_serial_dev: current serial device + */ + struct udevice *cur_serial_dev; + /** + * @arch: architecture-specific data + */ + struct arch_global_data arch; #ifdef CONFIG_CONSOLE_RECORD - struct membuff console_out; /* console output */ - struct membuff console_in; /* console input */ + /** + * @console_out: output buffer for console recording + * + * This buffer is used to collect output during console recording. + */ + struct membuff console_out; + /** + * @console_in: input buffer for console recording + * + * If console recording is activated, this buffer can be used to + * emulate input. + */ + struct membuff console_in; #endif #ifdef CONFIG_DM_VIDEO - ulong video_top; /* Top of video frame buffer area */ - ulong video_bottom; /* Bottom of video frame buffer area */ + /** + * @video_top: top of video frame buffer area + */ + ulong video_top; + /** + * @video_bottom: bottom of video frame buffer area + */ + ulong video_bottom; #endif #ifdef CONFIG_BOOTSTAGE - struct bootstage_data *bootstage; /* Bootstage information */ - struct bootstage_data *new_bootstage; /* Relocated bootstage info */ + /** + * @bootstage: boot stage information + */ + struct bootstage_data *bootstage; + /** + * @new_bootstage: relocated boot stage information + */ + struct bootstage_data *new_bootstage; #endif #ifdef CONFIG_LOG - int log_drop_count; /* Number of dropped log messages */ - int default_log_level; /* For devices with no filters */ - struct list_head log_head; /* List of struct log_device */ + /** + * @log_drop_count: number of dropped log messages + * + * This counter is incremented for each log message which can not + * be processed because logging is not yet available as signaled by + * flag %GD_FLG_LOG_READY in @flags. + */ + int log_drop_count; + /** + * @default_log_level: default logging level + * + * For logging devices without filters @default_log_level defines the + * logging level, cf. &enum log_level_t. + */ + int default_log_level; + /** + * @log_head: list of logging devices + */ + struct list_head log_head; + /** + * @log_fmt: bit mask for logging format + * + * The @log_fmt bit mask selects the fields to be shown in log messages. + * &enum log_fmt defines the bits of the bit mask. + */ int log_fmt; /* Mask containing log format info */ #endif #if CONFIG_IS_ENABLED(BLOBLIST) - struct bloblist_hdr *bloblist; /* Bloblist information */ - struct bloblist_hdr *new_bloblist; /* Relocated blolist info */ + /** + * @bloblist: blob list information + */ + struct bloblist_hdr *bloblist; + /** + * @new_bloblist: relocated blob list information + */ + struct bloblist_hdr *new_bloblist; # ifdef CONFIG_SPL + /** + * @spl_handoff: SPL hand-off information + */ struct spl_handoff *spl_handoff; # endif #endif #if defined(CONFIG_TRANSLATION_OFFSET) + /** + * @translation_offset: optional translation offset + * + * See CONFIG_TRANSLATION_OFFSET. + */ fdt_addr_t translation_offset; /* optional translation offset */ #endif #if CONFIG_IS_ENABLED(WDT) + /** + * @watchdog_dev: watchdog device + */ struct udevice *watchdog_dev; #endif -} gd_t; +};
+/** + * gd_board_type() - retrieve board type + * + * Return: global board type + */ #ifdef CONFIG_BOARD_TYPES #define gd_board_type() gd->board_type #else -- 2.28.0

Add the description of the global data pointer to the generated HTML documentation.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- v2: no change --- doc/develop/global_data.rst | 53 +++++++++++++++++++++++++++++++++++++ doc/develop/index.rst | 1 + 2 files changed, 54 insertions(+) create mode 100644 doc/develop/global_data.rst
diff --git a/doc/develop/global_data.rst b/doc/develop/global_data.rst new file mode 100644 index 0000000000..9e7c8a24da --- /dev/null +++ b/doc/develop/global_data.rst @@ -0,0 +1,53 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +Global data +=========== + +Globally required fields are held in the global data structure. A pointer to the +structure is available as symbol gd. The symbol is made available by the macro +%DECLARE_GLOBAL_DATA_PTR. + +Register pointing to global data +-------------------------------- + +On most architectures the global data pointer is stored in a register. + ++------------+----------+ +| ARC | r25 | ++------------+----------+ +| ARM 32bit | r9 | ++------------+----------+ +| ARM 64bit | x18 | ++------------+----------+ +| M68000 | d7 | ++------------+----------+ +| MicroBlaze | r31 | ++------------+----------+ +| NDS32 | r10 | ++------------+----------+ +| Nios II | gp | ++------------+----------+ +| PowerPC | r2 | ++------------+----------+ +| RISC-V | gp (x3) | ++------------+----------+ +| SuperH | r13 | ++------------+----------+ + +The sandbox, x86, and Xtensa are notable exceptions. + +Clang for ARM does not support assigning a global register. When using Clang +gd is defined as an inline function using assembly code. This adds a few bytes +to the code size. + +Binaries called by U-Boot are not aware of the register usage and will not +conserve gd. UEFI binaries call the API provided by U-Boot and may return to +U-Boot. The value of gd has to be saved every time U-Boot is left and restored +whenever U-Boot is reentered. This is also relevant for the implementation of +function tracing. For setting the value of gd function set_gd() can be used. + +Global data structure +--------------------- + +.. kernel-doc:: include/asm-generic/global_data.h + :internal: diff --git a/doc/develop/index.rst b/doc/develop/index.rst index 98a95ad434..89e80eab94 100644 --- a/doc/develop/index.rst +++ b/doc/develop/index.rst @@ -9,4 +9,5 @@ Develop U-Boot
coccinelle crash_dumps + global_data logging -- 2.28.0
participants (2)
-
Heinrich Schuchardt
-
Simon Glass