[Qemu-devel] [PATCH v2] sdhci: add quirk property for card insert interrupt status on Raspberry Pi

[Andrew Baumann]

This quirk is a workaround for the following hardware behaviour, on
which UEFI (specifically, the bootloader for Windows on Pi2) depends:

1. at boot with an SD card present, the interrupt status/enable
   registers are initially zero
2. upon enabling it in the interrupt enable register, the card insert
   bit in the interrupt status register is immediately set
3. after a subsequent controller reset, the card insert interrupt does
   not fire, even if enabled in the interrupt enable register

The implementation uses a pending_insert bool, which can be set via a
property (enabling the quirk) and is cleared and remains clear once
the interrupt has been delivered.

Signed-off-by: Andrew Baumann <address@hidden>
---

This depends on
https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg04895.html
(revert of the broken noeject_quirk).

Notes:
    v2: changed implementation to use pending_insert bool rather than
    masking norintsts at read time, since the older version diverges from
    actual hardware behaviour when an interrupt is masked without being
    acked

Peter, am I doing the right thing with the vmstate here?

 hw/sd/sdhci.c         | 12 +++++++++++-
 include/hw/sd/sdhci.h |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index dd83e89..a5364fd 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -196,6 +196,7 @@ static void sdhci_reset(SDHCIState *s)
     sd_set_cb(s->card, s->ro_cb, s->eject_cb);
     s->data_count = 0;
     s->stopped_state = sdhc_not_stopped;
+    s->pending_insert = false;
 }
 
 static void sdhci_data_transfer(void *opaque);
@@ -1087,6 +1088,12 @@ sdhci_write(void *opaque, hwaddr offset, uint64_t val, 
unsigned size)
         } else {
             s->norintsts &= ~SDHC_NIS_ERR;
         }
+        /* Quirk for Raspberry Pi: pending card insert interrupt
+         * appears when first enabled after power on */
+        if ((s->norintstsen & SDHC_NISEN_INSERT) && s->pending_insert) {
+            s->norintsts |= SDHC_NIS_INSERT;
+            s->pending_insert = false;
+        }
         sdhci_update_irq(s);
         break;
     case SDHC_NORINTSIGEN:
@@ -1180,7 +1187,7 @@ static void sdhci_uninitfn(SDHCIState *s)
 
 const VMStateDescription sdhci_vmstate = {
     .name = "sdhci",
-    .version_id = 1,
+    .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(sdmasysad, SDHCIState),
@@ -1211,6 +1218,7 @@ const VMStateDescription sdhci_vmstate = {
         VMSTATE_VBUFFER_UINT32(fifo_buffer, SDHCIState, 1, NULL, 0, buf_maxsz),
         VMSTATE_TIMER_PTR(insert_timer, SDHCIState),
         VMSTATE_TIMER_PTR(transfer_timer, SDHCIState),
+        VMSTATE_BOOL(pending_insert, SDHCIState),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -1227,6 +1235,8 @@ static Property sdhci_pci_properties[] = {
     DEFINE_PROP_UINT32("capareg", SDHCIState, capareg,
             SDHC_CAPAB_REG_DEFAULT),
     DEFINE_PROP_UINT32("maxcurr", SDHCIState, maxcurr, 0),
+    DEFINE_PROP_BOOL("pending-insert-quirk", SDHCIState, pending_insert,
+                     false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/sd/sdhci.h b/include/hw/sd/sdhci.h
index e78d938..c70be14 100644
--- a/include/hw/sd/sdhci.h
+++ b/include/hw/sd/sdhci.h
@@ -77,6 +77,7 @@ typedef struct SDHCIState {
     uint32_t buf_maxsz;
     uint16_t data_count;   /* current element in FIFO buffer */
     uint8_t  stopped_state;/* Current SDHC state */
+    bool     pending_insert;/* Quirk for Raspberry Pi card insert interrupt */
     /* Buffer Data Port Register - virtual access point to R and W buffers */
     /* Software Reset Register - always reads as 0 */
     /* Force Event Auto CMD12 Error Interrupt Reg - write only */
-- 
2.5.3