Re: [Qemu-devel] [PATCHv4 5/5] fw_cfg: move QOM type defines and fw_cfg types into fw_cfg.h

[Laszlo Ersek]

On 06/16/17 15:23, Mark Cave-Ayland wrote:
> This allows the device to be instantiated externally for boards that
> wish to wire up the fw_cfg device themselves.
> 
> Signed-off-by: Mark Cave-Ayland <address@hidden>
> ---
>  hw/nvram/fw_cfg.c         |   56 -------------------------------------------
>  include/hw/nvram/fw_cfg.h |   58 
> +++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+), 56 deletions(-)
> 
> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> index b5f10ac..00771c9 100644
> --- a/hw/nvram/fw_cfg.c
> +++ b/hw/nvram/fw_cfg.c
> @@ -40,14 +40,6 @@
>  #define FW_CFG_NAME "fw_cfg"
>  #define FW_CFG_PATH "/machine/" FW_CFG_NAME
>  
> -#define TYPE_FW_CFG     "fw_cfg"
> -#define TYPE_FW_CFG_IO  "fw_cfg_io"
> -#define TYPE_FW_CFG_MEM "fw_cfg_mem"
> -
> -#define FW_CFG(obj)     OBJECT_CHECK(FWCfgState,    (obj), TYPE_FW_CFG)
> -#define FW_CFG_IO(obj)  OBJECT_CHECK(FWCfgIoState,  (obj), TYPE_FW_CFG_IO)
> -#define FW_CFG_MEM(obj) OBJECT_CHECK(FWCfgMemState, (obj), TYPE_FW_CFG_MEM)
> -
>  /* FW_CFG_VERSION bits */
>  #define FW_CFG_VERSION      0x01
>  #define FW_CFG_VERSION_DMA  0x02
> @@ -61,54 +53,6 @@
>  
>  #define FW_CFG_DMA_SIGNATURE 0x51454d5520434647ULL /* "QEMU CFG" */
>  
> -typedef struct FWCfgEntry {
> -    uint32_t len;
> -    bool allow_write;
> -    uint8_t *data;
> -    void *callback_opaque;
> -    FWCfgReadCallback read_callback;
> -} FWCfgEntry;
> -
> -struct FWCfgState {
> -    /*< private >*/
> -    SysBusDevice parent_obj;
> -    /*< public >*/
> -
> -    uint16_t file_slots;
> -    FWCfgEntry *entries[2];
> -    int *entry_order;
> -    FWCfgFiles *files;
> -    uint16_t cur_entry;
> -    uint32_t cur_offset;
> -    Notifier machine_ready;
> -
> -    int fw_cfg_order_override;
> -
> -    bool dma_enabled;
> -    dma_addr_t dma_addr;
> -    AddressSpace *dma_as;
> -    MemoryRegion dma_iomem;
> -};
> -
> -struct FWCfgIoState {
> -    /*< private >*/
> -    FWCfgState parent_obj;
> -    /*< public >*/
> -
> -    MemoryRegion comb_iomem;
> -    uint32_t iobase, dma_iobase;
> -};
> -
> -struct FWCfgMemState {
> -    /*< private >*/
> -    FWCfgState parent_obj;
> -    /*< public >*/
> -
> -    MemoryRegion ctl_iomem, data_iomem;
> -    uint32_t data_width;
> -    MemoryRegionOps wide_data_ops;
> -};
> -
>  #define JPG_FILE 0
>  #define BMP_FILE 1
>  
> diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
> index b980cba..a16907a 100644
> --- a/include/hw/nvram/fw_cfg.h
> +++ b/include/hw/nvram/fw_cfg.h
> @@ -3,6 +3,16 @@
>  
>  #include "exec/hwaddr.h"
>  #include "hw/nvram/fw_cfg_keys.h"
> +#include "hw/sysbus.h"
> +#include "sysemu/dma.h"
> +
> +#define TYPE_FW_CFG     "fw_cfg"
> +#define TYPE_FW_CFG_IO  "fw_cfg_io"
> +#define TYPE_FW_CFG_MEM "fw_cfg_mem"
> +
> +#define FW_CFG(obj)     OBJECT_CHECK(FWCfgState,    (obj), TYPE_FW_CFG)
> +#define FW_CFG_IO(obj)  OBJECT_CHECK(FWCfgIoState,  (obj), TYPE_FW_CFG_IO)
> +#define FW_CFG_MEM(obj) OBJECT_CHECK(FWCfgMemState, (obj), TYPE_FW_CFG_MEM)
>  
>  typedef struct FWCfgFile {
>      uint32_t  size;        /* file size */
> @@ -35,6 +45,54 @@ typedef struct FWCfgDmaAccess {
>  
>  typedef void (*FWCfgReadCallback)(void *opaque);
>  
> +typedef struct FWCfgEntry {
> +    uint32_t len;
> +    bool allow_write;
> +    uint8_t *data;
> +    void *callback_opaque;
> +    FWCfgReadCallback read_callback;
> +} FWCfgEntry;
> +
> +struct FWCfgState {
> +    /*< private >*/
> +    SysBusDevice parent_obj;
> +    /*< public >*/
> +
> +    uint16_t file_slots;
> +    FWCfgEntry *entries[2];
> +    int *entry_order;
> +    FWCfgFiles *files;
> +    uint16_t cur_entry;
> +    uint32_t cur_offset;
> +    Notifier machine_ready;
> +
> +    int fw_cfg_order_override;
> +
> +    bool dma_enabled;
> +    dma_addr_t dma_addr;
> +    AddressSpace *dma_as;
> +    MemoryRegion dma_iomem;
> +};
> +
> +struct FWCfgIoState {
> +    /*< private >*/
> +    FWCfgState parent_obj;
> +    /*< public >*/
> +
> +    MemoryRegion comb_iomem;
> +    uint32_t iobase, dma_iobase;
> +};
> +
> +struct FWCfgMemState {
> +    /*< private >*/
> +    FWCfgState parent_obj;
> +    /*< public >*/
> +
> +    MemoryRegion ctl_iomem, data_iomem;
> +    uint32_t data_width;
> +    MemoryRegionOps wide_data_ops;
> +};
> +
>  /**
>   * fw_cfg_add_bytes:
>   * @s: fw_cfg device being modified
> 

This patch is generally good, but I'd like to suggest improvements:

(1) In the commit message, please mention that we are exposing the
internals of FWCfgIoState and FWCfgMemState so that board code can map
the MemoryRegion fields (such as comb_iomem) *by name*.

(2) FWCfgEntry need not be moved from the C file to the header file,
since we never depend on the *size* of that structure. Instead, please
add a single line to "include/qemu/typedefs.h":

   typedef struct FWCfgEntry FWCfgEntry;

and modify

    typedef struct FWCfgEntry {
    ...
    } FWCfgEntry;

in "fw_cfg.c" to just

    struct FWCfgEntry {
    ...
    };

Then "fw_cfg.h" can simply include "typedefs.h" and say

    ...
    FWCfgEntry *entries[2];
    ...

IOW, it's fine to leave FWCfgEntry an incomplete type in "fw_cfg.h".

(3) When you fix up patch #1 like I requested, removing the
"FWCfgIoState.iobase" and "FWCfgIoState.dma_iobase" fields, please don't
forget to update this patch as well, so that you not re-introduce those
fields in the header file.

... I'm positively satisfied with this series (I plan to "grant" my R-b
for PATCH v5 5/5, with the above updates), but given that I'm no QOM
expert by any means, I'd like someone with more QOM experience to review
the patchset as well.

Thanks!
Laszlo