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hw/sd/omap_mmc: Split 'pseudo-reset' from 'power-on-reset' 

DeviceClass::reset models a "cold power-on" reset which can
also be used to powercycle a device; but there is no "hot reset"
(a.k.a. soft-reset) method available.

The OMAP MMC Power-Up Control bit is not designed to powercycle
a card, but to disable it without powering it off (pseudo-reset):

  Multimedia Card (MMC/SD/SDIO) Interface [SPRU765A]

  MMC_CON[11] Power-Up Control (POW)
  This bit must be set to 1 before any valid transaction to either
  MMC/SD or SPI memory cards.
  When 1, the card is considered powered-up and the controller core
  is enabled.
  When 0, the card is considered powered-down (system dependent),
  and the controller core logic is in pseudo-reset state. This is,
  the MMC_STAT flags and the FIFO pointers are reset, any access to
  MMC_DATA[DATA] has no effect, a write into the MMC.CMD register
  is ignored, and a setting of MMC_SPI[STR] to 1 is ignored.

By splitting the 'pseudo-reset' code out of the 'power-on' reset
function, this patch fixes a latent bug in omap_mmc_write(MMC_CON)i
recently exposed by ecd219f7ab.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180706162155.8432-2-f4bug@amsat.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2018-07-09 14:51:34 +01:00 committed by Peter Maydell
parent 973558a3f8
commit 7abf56eed1
1 changed files with 11 additions and 3 deletions
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14
hw/sd/omap_mmc.c
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@ -1,6 +1,8 @@
/*
* OMAP on-chip MMC/SD host emulation.
*
* Datasheet: TI Multimedia Card (MMC/SD/SDIO) Interface (SPRU765A)
*
* Copyright (C) 2006-2007 Andrzej Zaborowski <balrog@zabor.org>
*
* This program is free software; you can redistribute it and/or
@ -278,6 +280,12 @@ static void omap_mmc_update(void *opaque)
omap_mmc_interrupts_update(s);
}
static void omap_mmc_pseudo_reset(struct omap_mmc_s *host)
{
host->status = 0;
host->fifo_len = 0;
}
void omap_mmc_reset(struct omap_mmc_s *host)
{
host->last_cmd = 0;
@ -286,11 +294,9 @@ void omap_mmc_reset(struct omap_mmc_s *host)
host->dw = 0;
host->mode = 0;
host->enable = 0;
host->status = 0;
host->mask = 0;
host->cto = 0;
host->dto = 0;
host->fifo_len = 0;
host->blen = 0;
host->blen_counter = 0;
host->nblk = 0;
@ -305,6 +311,8 @@ void omap_mmc_reset(struct omap_mmc_s *host)
qemu_set_irq(host->coverswitch, host->cdet_state);
host->clkdiv = 0;
omap_mmc_pseudo_reset(host);
/* Since we're still using the legacy SD API the card is not plugged
* into any bus, and we must reset it manually. When omap_mmc is
* QOMified this must move into the QOM reset function.
@ -459,7 +467,7 @@ static void omap_mmc_write(void *opaque, hwaddr offset,
if (s->dw != 0 && s->lines < 4)
printf("4-bit SD bus enabled\n");
if (!s->enable)
omap_mmc_reset(s);
omap_mmc_pseudo_reset(s);
break;
case 0x10: /* MMC_STAT */