[PATCH v3 0/8] m25p80: Add SFDP support

["Cédric Le Goater" <clg@kaod.org>]

Hello, 

This is a refresh of a patchset sent long ago [1] adding support for
JEDEC STANDARD JESD216 Serial Flash Discovery Parameters (SFDP). SFDP
describes the features of a serial flash device using a set of internal
parameter tables. Support in Linux has been added some time ago and
the spi-nor driver is using it more often to detect the flash settings
and even flash models.

Francisco and I are not entirely satisfied with the way the tables are
defined. We add some private discussion on how to resolve that but
neither of us had the time to pursue the study. Latest Francisco
proposal was : 

    #define define_sfdp_read_wrap(model, wrap_sz)            \
    uint8_t m25p80_sdfp_read_##model(SFDPTable t, uint32_t addr) \
    {                                                            \
         return m25p80_sdfp_read(t, addr & (wrap_sz-1));          \
    }
    ...
    define_sfdp_read_wrap(mt25ql512ab, SZ_256)
    
    A new variable in the section would solve it aswell but not convinced at the
    moment if it is clear enough:
    
    typedef struct SFDPSection {
         const uint32_t addr;
         const uint32_t size;
         const uint32_t wrap_sz;
         const uint8_t *data;
    } SFDPSection;
    
    #define SFDP_RAW(start_addr, vals...) \
    {                                     \
       .addr = start_addr,                 \
       .size = sizeof((uint8_t[]){vals}),  \
       .data = (const uint8_t[]){vals}     \
    }
    
    #define SFDP_RAW_WRAP(start_addr, _wrap_sz, vals...) \
    {                                     \
       .addr = start_addr,                 \
       .size = sizeof((uint8_t[]){vals}),  \
       .wrap_sz = _wrap_sz,                \
       .data = (const uint8_t[]){vals}     \
    }
    
    #define SFDP_TABLE_END() { 0 }
    #define IS_SFDP_END(x) (x.size == 0)
    
    #define M35T4545_WRAP_SZ 0x100
    
    static const SFDPTable m35t4545 = {
         SFDP_RAW_WRAP(0, M35T4545_WRAP_SZ,
                       0x53, 0x46, 0x44, 0x50, 0x00, 0x01, 0x00, 0xff,
                       0x00, 0x00, 0x01, 0x09, 0x30, 0x00, 0x00, 0xff),
    
         SFDP_RAW(0x38,
                  0xe5, 0x20, 0xfb, 0xff, 0xff, 0xff, 0xff, 0x0f,
                  0x29, 0xeb, 0x27, 0x6b, 0x08, 0x3b, 0x27, 0xbb,
                  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x27, 0xbb,
                  0xff, 0xff, 0x29, 0xeb, 0x0c, 0x20, 0x10, 0xd8,
                  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff),
    
         SFDP_TABLE_END()
    };
    
    uint8_t m25p80_sfdp_read(SFDPTable t, uint32_t addr)
    {
         if (t[0].wrap_sz) {
             addr &= (t.wrap_sz-1);
         }
    
         for (int i = 0; !IS_SFDP_END(t[i]); i++) {
             if (addr >= t[i].addr && addr < (t[i].addr + t[i].size)) {
                 return t[i].data[addr];
             }
         }
         return 0xFF;
    }

Since there is a need, we have been using these patches in OpenBMC for
some time now and other projects/companies have requested it, I am
resending the patchset as it is to restart the discussion.

Thanks,

C.

Cédric Le Goater (8):
  m25p80: Add basic support for the SFDP command
  m25p80: Add the n25q256a SFDP table
  m25p80: Add the mx25l25635e SFPD table
  m25p80: Add the mx25l25635f SFPD table
  m25p80: Add the mx66l1g45g SFDP table
  m25p80: Add the w25q256 SFPD table
  m25p80: Add the w25q512jv SFPD table
  arm/aspeed: Replace mx25l25635e chip model

 hw/block/m25p80_sfdp.h |  27 ++++
 hw/arm/aspeed.c        |   6 +-
 hw/block/m25p80.c      |  49 ++++++-
 hw/block/m25p80_sfdp.c | 296 +++++++++++++++++++++++++++++++++++++++++
 MAINTAINERS            |   2 +-
 hw/block/meson.build   |   1 +
 hw/block/trace-events  |   1 +
 7 files changed, 371 insertions(+), 11 deletions(-)
 create mode 100644 hw/block/m25p80_sfdp.h
 create mode 100644 hw/block/m25p80_sfdp.c

-- 
2.35.3