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authorPeter Crosthwaite <crosthwaitepeter@gmail.com>2015-12-21 14:47:47 -0800
committerStefan Hajnoczi <stefanha@redhat.com>2015-12-22 16:34:26 +0800
commit6890a695d954f33c8a9c4efd3037fdb707fe28ec (patch)
tree5bcdb745f5d310602d704fef18be659cdb1a3bb0 /hw
parentd6b6913276535bc0bc0d519d94ba0c908d8cfed8 (diff)
sd: sdhci: Delete over-zealous power check
This check was conditionalising SD card operation on the card being powered by the SDHCI host controller. It is however possible (particularly in embedded systems) for the power control of the SD card to be managed outside of SDHCI. This can be as trivial as hard-wiring the SD slot VCC to a constant power-rail. This means the guest SDHCI can validly opt-out of the SDHCI power control feature while still using the card. So delete this check to allow operation of the card with SDHCI power control. This is needed for at least Xilinx Zynq and Raspberry Pi, and also makes Freescale i.MX25 work for me. The digilent Zybo board has a public schematic which shows SD VCC hardwiring: http://digilentinc.com/Data/Products/ZYBO/ZYBO_sch_VB.3.pdf bottom of page 3. Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Reviewed-by: Sai Pavan Boddu <saipava@xilinx.com> Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com> Message-id: 1450738069-18664-2-git-send-email-Andrew.Baumann@microsoft.com [AB: Add Pi to list of devices fixed in commit message] Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/sd/sdhci.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index 861276065f..bc39d48ac4 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -831,7 +831,7 @@ static void sdhci_data_transfer(void *opaque)
static bool sdhci_can_issue_command(SDHCIState *s)
{
- if (!SDHC_CLOCK_IS_ON(s->clkcon) || !(s->pwrcon & SDHC_POWER_ON) ||
+ if (!SDHC_CLOCK_IS_ON(s->clkcon) ||
(((s->prnsts & SDHC_DATA_INHIBIT) || s->stopped_state) &&
((s->cmdreg & SDHC_CMD_DATA_PRESENT) ||
((s->cmdreg & SDHC_CMD_RESPONSE) == SDHC_CMD_RSP_WITH_BUSY &&