The i.MX (u)SDHC gates the SD card clock in hardware and has no software-visible "SD Clock Enable" bit, so the Linux sdhci-esdhc-imx driver programs only the divider and the internal-clock enable and never sets SDHC_CLOCK_SDCLK_EN. The generic command-dispatch gate, sdhci_can_issue_command() -> SDHC_CLOCK_IS_ON(), requires that bit, so under Linux every command issued to such a controller is silently dropped: no command-complete or command-timeout interrupt is raised, and the guest mmc layer falls back to a 10s host-side timeout per command, indefinitely. (The existing VENDORSPEC->clkcon mirror only covered the U-Boot fsl_esdhc_imx clock path, which does toggle the VENDORSPEC enable bits; the upstream Linux driver does not.)
On the i.MX 95 machine this wedges shutdown: with no backing storage the empty eMMC slot (non-removable, always probed) and SD slot both spin on these 10s timeouts, so device_shutdown() never returns and the guest never reaches PSCI SYSTEM_OFF -- a guest poweroff fails to terminate QEMU, and the controllers spew sdhci-esdhc-imx debug-status dumps the whole time. Add SDHCI_QUIRK_SDCLK_AUTO_GATE: when set, the controller is considered ready to issue commands once the internal clock is enabled and stable, without also requiring SDHC_CLOCK_SDCLK_EN. Set it on the three i.MX variants (imx-usdhc, fsl-esdhc-be, fsl-esdhc-le). With the clock gate relaxed, an absent card is reported promptly as a command timeout, card init fails in milliseconds instead of 10s, device_shutdown() completes, and guest poweroff terminates the VM cleanly. The change is strictly more permissive than the previous gate (every state that satisfied SDHC_CLOCK_IS_ON still dispatches), so controllers without the quirk are unaffected; the sdhci qtests (xlnx-zcu102 and sdhci-pci, neither of which sets the quirk) still pass. Signed-off-by: Kyle Fox <[email protected]> --- hw/sd/sdhci.c | 25 +++++++++++++++++++++---- include/hw/sd/sdhci.h | 11 +++++++++++ 2 files changed, 32 insertions(+), 4 deletions(-) diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c index 4ad96a8760..d52335424b 100644 --- a/hw/sd/sdhci.c +++ b/hw/sd/sdhci.c @@ -1013,9 +1013,26 @@ static void sdhci_data_transfer(void *opaque) } } +static bool sdhci_clock_is_on(SDHCIState *s) +{ + /* + * The i.MX (u)SDHC has no software SD-clock-enable bit (the card clock + * is auto-gated by hardware), so its driver never sets + * SDHC_CLOCK_SDCLK_EN. For such a controller, treat the clock as + * running once the internal clock is enabled and stable; otherwise + * every command would be silently dropped (no completion/timeout IRQ), + * stalling the guest on 10s host-side timeouts. + */ + if (s->quirks & SDHCI_QUIRK_SDCLK_AUTO_GATE) { + return (s->clkcon & (SDHC_CLOCK_INT_EN | SDHC_CLOCK_INT_STABLE)) == + (SDHC_CLOCK_INT_EN | SDHC_CLOCK_INT_STABLE); + } + return SDHC_CLOCK_IS_ON(s->clkcon); +} + static bool sdhci_can_issue_command(SDHCIState *s) { - if (!SDHC_CLOCK_IS_ON(s->clkcon) || + if (!sdhci_clock_is_on(s) || (((s->prnsts & SDHC_DATA_INHIBIT) || s->stopped_state) && ((s->cmdreg & SDHC_CMD_DATA_PRESENT) || ((s->cmdreg & SDHC_CMD_RESPONSE) == SDHC_CMD_RSP_WITH_BUSY && @@ -1905,7 +1922,7 @@ static void fsl_esdhc_be_init(Object *obj) DeviceState *dev = DEVICE(obj); s->io_ops = &esdhc_mmio_be_ops; - s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ; + s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ | SDHCI_QUIRK_SDCLK_AUTO_GATE; qdev_prop_set_uint8(dev, "sd-spec-version", 2); } @@ -1930,7 +1947,7 @@ static void fsl_esdhc_le_init(Object *obj) DeviceState *dev = DEVICE(obj); s->io_ops = &esdhc_mmio_le_ops; - s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ; + s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ | SDHCI_QUIRK_SDCLK_AUTO_GATE; qdev_prop_set_uint8(dev, "sd-spec-version", 2); } @@ -1951,7 +1968,7 @@ static void imx_usdhc_init(Object *obj) DeviceState *dev = DEVICE(obj); s->io_ops = &usdhc_mmio_ops; - s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ; + s->quirks = SDHCI_QUIRK_NO_BUSY_IRQ | SDHCI_QUIRK_SDCLK_AUTO_GATE; qdev_prop_set_uint8(dev, "sd-spec-version", 3); } diff --git a/include/hw/sd/sdhci.h b/include/hw/sd/sdhci.h index a9da6203fc..d96f9c1dfa 100644 --- a/include/hw/sd/sdhci.h +++ b/include/hw/sd/sdhci.h @@ -115,6 +115,17 @@ typedef struct SDHCIState SDHCIState; */ #define SDHCI_QUIRK_NO_BUSY_IRQ BIT(14) +/* + * The i.MX (u)SDHC gates the SD card clock automatically and has no + * software-visible "SD Clock Enable" bit: its driver programs only the + * divider and the internal-clock enable, never SDHC_CLOCK_SDCLK_EN. With + * this quirk the controller is considered ready to issue commands once the + * internal clock is enabled and stable, instead of also requiring + * SDHC_CLOCK_SDCLK_EN (which such a driver never sets). QEMU-internal bit, + * not mirrored from Linux. + */ +#define SDHCI_QUIRK_SDCLK_AUTO_GATE BIT(16) + #define TYPE_PCI_SDHCI "sdhci-pci" DECLARE_INSTANCE_CHECKER(SDHCIState, PCI_SDHCI, TYPE_PCI_SDHCI) -- 2.34.1
