User talk:MrNuke/Block Device API: Difference between revisions
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(Created page with "== Ideas for generic handling of devices == IMPORTANT! Feel free to edit this page to share your thoughts and ideas. This is the official MMC open brainstorming page. === Pr...") |
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void (*power)(int); /* power mgt: power(1) ? on, power (0) ? off */ | void (*power)(int); /* power mgt: power(1) ? on, power (0) ? off */ | ||
}; | }; | ||
==== Comments ==== | |||
This API is too big and too powerful for the needs of coreboot. It will need to be trimmed to present a coreboot-centric (simpler) interface. | |||
==== Questions ==== | ==== Questions ==== | ||
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#* think "Device specfic storage drivers -> [*] Allwinner A10 MMC driver" in '''libpayload''' config | #* think "Device specfic storage drivers -> [*] Allwinner A10 MMC driver" in '''libpayload''' config | ||
# More questions coming soon (TM) | # More questions coming soon (TM) | ||
==== Resources ==== | |||
* Existing, but not merged, MMC code for cubieboard: [https://github.com/mrnuke/coreboot/commits/cubie_mmc mrnuke's github branch] | |||
Latest revision as of 20:11, 6 March 2014
Ideas for generic handling of devices
IMPORTANT! Feel free to edit this page to share your thoughts and ideas. This is the official MMC open brainstorming page.
Proposal 1: Unified API
Chan is an IO channel.
This struct is used in Inferno and has been for a long time; so it works. It's also in the opcodes somewhat like what we did for EMMC on ARM.
struct Dev
{
char* name;
void (*reset)(void);
void (*init)(void);
void (*shutdown)(void);
Chan* (*attach)(char*); /* tell the device you want to use it */
Walkqid* (*walk)(Chan*, Chan*, char**, int); /* walk to a name in the device's managed name space; return a handle */
int (*stat)(Chan*, uchar*, int); // status info
Chan* (*open)(Chan*, int); /* get access to a resource in the device name space */
void (*close)(Chan*); /* tell it you are done with whatever it is. */
long (*read)(Chan*, void*, long, vlong);
long (*write)(Chan*, void*, long, vlong);
void (*power)(int); /* power mgt: power(1) ? on, power (0) ? off */
};
Comments
This API is too big and too powerful for the needs of coreboot. It will need to be trimmed to present a coreboot-centric (simpler) interface.
Questions
- Do we want to expose or hide the block nature of some devces (i.e. force reading multiples of blocksize, or allow reading any number of bytes, with no alignment requirement) ?
- How do we connect the dots, such that most of the details can be handled transparently ?
- How simple or complex do we want the API to be such that it can work in any stage (including bootblock, assuming some SRAM and a stack are available) ?
- Can we integrate this into libpayload such that the same sources can be used for both coreboot and libpayload ?
- think "Device specfic storage drivers -> [*] Allwinner A10 MMC driver" in libpayload config
- More questions coming soon (TM)
Resources
- Existing, but not merged, MMC code for cubieboard: mrnuke's github branch