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mmc: Remove alignment hole for cmdidx in struct mmc_cmd

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The alignment hole caused by cmdidx in struct mmc_cmd cause strange
issues together with the peephole2 optimization on Amlogic SoCs.
Following was observed while working on SPL support for Amlogic SoCs.

sd_get_capabilities() normally issue a CMD55 followed by a CMD51.
However, on at least Amlogic S905 (Cortex-A53) and S905X3 (Cortex-A55),
CMD55 was instead followed by CMD8 (and a few reties) in SPL.

Code from the call site:

  cmd.cmdidx = SD_CMD_APP_SEND_SCR; // 51
  ...
  data.blocksize = 8;
  ...
  err = mmc_send_cmd_retry(mmc, &cmd, &data, 3);

Running the code with MMC_TRACE enabled shows:

CMD_SEND:55
                ARG                      0x50480000
                MMC_RSP_R1,5,6,7         0x00000920
CMD_SEND:8
                ARG                      0x00000000
                RET                      -110

Removing the alignment hole by changing cmdidx from ushort to uint or
building with -fno-peephole2 flag seem to resolve this issue.

CMD_SEND:55
                ARG                      0x50480000
                MMC_RSP_R1,5,6,7         0x00000920
CMD_SEND:51
                ARG                      0x00000000
                MMC_RSP_R1,5,6,7         0x00000920

Same issue was observed building U-Boot with gcc 8 - 13.

Remove this alignment hole by changing cmdidx from ushort to uint.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Tom Rini <trini@konsulko.com>
This commit is contained in:
Jonas Karlman 2024-01-27 16:29:21 +00:00 • committed by Tom Rini
parent f55fa90a95
commit 2348dd8e41
1 changed files with 1 additions and 1 deletions
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2
include/mmc.h
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@ -431,7 +431,7 @@ struct mmc_cid {
};
struct mmc_cmd {
ushort cmdidx;
uint cmdidx;
uint resp_type;
uint cmdarg;
uint response[4];