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authorPeter Maydell <peter.maydell@linaro.org>2018-04-10 13:02:25 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-04-10 13:02:25 +0100
commitf3d9fe8f95964308564f0987f7a5e2a88cc887be (patch)
tree88034bd02328c876031936d2f21565dd6311e9a0 /hw/sd/bcm2835_sdhost.c
parentb318f3265c4cdc7ae7c214bd931abad5bd7c6a5e (diff)
downloadqemu-arm-f3d9fe8f95964308564f0987f7a5e2a88cc887be.tar.gz
hw/sd/bcm2835_sdhost: Don't raise spurious interrupts
The Linux bcm2835_sdhost driver doesn't work on QEMU, because our model raises spurious data interrupts. Our function bcm2835_sdhost_fifo_run() will flag an interrupt any time it is called with s->datacnt == 0, even if the host hasn't actually issued a data read or write command yet. This means that the driver gets a spurious data interrupt as soon as it enables IRQs and then does something else that causes us to call the fifo_run routine, like writing to SDHCFG, and before it does the write to SDCMD to issue the read. The driver's IRQ handler then spins forever complaining that there's no data and the SD controller isn't in a state where there's going to be any data: [ 41.040738] sdhost-bcm2835 3f202000.mmc: fsm 1, hsts 00000000 [ 41.042059] sdhost-bcm2835 3f202000.mmc: fsm 1, hsts 00000000 (continues forever). Move the interrupt flag setting to more plausible places: * for BUSY, raise this as soon as a BUSYWAIT command has executed * for DATA, raise this when the FIFO has any space free (for a write) or any data in it (for a read) * for BLOCK, raise this when the data count is 0 and we've actually done some reading or writing This is pure guesswork since the documentation for this hardware is not public, but it is sufficient to get the Linux bcm2835_sdhost driver to work. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Gerd Hoffmann <kraxel@redhat.com> Message-id: 20180319161556.16446-3-peter.maydell@linaro.org
Diffstat (limited to 'hw/sd/bcm2835_sdhost.c')
-rw-r--r--hw/sd/bcm2835_sdhost.c46
1 files changed, 26 insertions, 20 deletions
diff --git a/hw/sd/bcm2835_sdhost.c b/hw/sd/bcm2835_sdhost.c
index 79f3c5ceeb..ebf3b926c2 100644
--- a/hw/sd/bcm2835_sdhost.c
+++ b/hw/sd/bcm2835_sdhost.c
@@ -137,6 +137,12 @@ static void bcm2835_sdhost_send_command(BCM2835SDHostState *s)
}
#undef RWORD
}
+ /* We never really delay commands, so if this was a 'busywait' command
+ * then we've completed it now and can raise the interrupt.
+ */
+ if ((s->cmd & SDCMD_BUSYWAIT) && (s->config & SDHCFG_BUSY_IRPT_EN)) {
+ s->status |= SDHSTS_BUSY_IRPT;
+ }
return;
error:
@@ -187,18 +193,27 @@ static void bcm2835_sdhost_fifo_run(BCM2835SDHostState *s)
n++;
if (n == 4) {
bcm2835_sdhost_fifo_push(s, value);
+ s->status |= SDHSTS_DATA_FLAG;
+ if (s->config & SDHCFG_DATA_IRPT_EN) {
+ s->status |= SDHSTS_SDIO_IRPT;
+ }
n = 0;
value = 0;
}
}
if (n != 0) {
bcm2835_sdhost_fifo_push(s, value);
+ s->status |= SDHSTS_DATA_FLAG;
}
} else { /* write */
n = 0;
while (s->datacnt > 0 && (s->fifo_len > 0 || n > 0)) {
if (n == 0) {
value = bcm2835_sdhost_fifo_pop(s);
+ s->status |= SDHSTS_DATA_FLAG;
+ if (s->config & SDHCFG_DATA_IRPT_EN) {
+ s->status |= SDHSTS_SDIO_IRPT;
+ }
n = 4;
}
n--;
@@ -207,29 +222,20 @@ static void bcm2835_sdhost_fifo_run(BCM2835SDHostState *s)
value >>= 8;
}
}
- }
- if (s->datacnt == 0) {
- s->status |= SDHSTS_DATA_FLAG;
-
- s->edm &= ~0xf;
- s->edm |= SDEDM_FSM_DATAMODE;
- trace_bcm2835_sdhost_edm_change("datacnt 0", s->edm);
-
- if (s->config & SDHCFG_DATA_IRPT_EN) {
- s->status |= SDHSTS_SDIO_IRPT;
- }
-
- if ((s->cmd & SDCMD_BUSYWAIT) && (s->config & SDHCFG_BUSY_IRPT_EN)) {
- s->status |= SDHSTS_BUSY_IRPT;
- }
-
- if ((s->cmd & SDCMD_WRITE_CMD) && (s->config & SDHCFG_BLOCK_IRPT_EN)) {
- s->status |= SDHSTS_BLOCK_IRPT;
+ if (s->datacnt == 0) {
+ s->edm &= ~SDEDM_FSM_MASK;
+ s->edm |= SDEDM_FSM_DATAMODE;
+ trace_bcm2835_sdhost_edm_change("datacnt 0", s->edm);
+
+ if ((s->cmd & SDCMD_WRITE_CMD) &&
+ (s->config & SDHCFG_BLOCK_IRPT_EN)) {
+ s->status |= SDHSTS_BLOCK_IRPT;
+ }
}
-
- bcm2835_sdhost_update_irq(s);
}
+ bcm2835_sdhost_update_irq(s);
+
s->edm &= ~(0x1f << 4);
s->edm |= ((s->fifo_len & 0x1f) << 4);
trace_bcm2835_sdhost_edm_change("fifo run", s->edm);