usb: dwc_otg: Use dma allocation for mphi dummy_send buffer

The FIQ driver used a kzalloc'ed buffer for dummy_send,
passing a kernel virtual address to the hardware block.
The buffer is only ever used for a dummy read, so it
should be harmless, but there is the chance that it will
cause exceptions.

Use a dma allocation so that we have a genuine bus address,
and read from that.
Free the allocation when done for good measure.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

diff --git a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
index 624bb79..3ac4c79 100644 (file)
--- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
@@ -1347,7 +1347,7 @@ void notrace dwc_otg_fiq_fsm(struct fiq_state *state, int num_channels)
        /* We got an interrupt, didn't handle it. */
        if (kick_irq) {
                state->mphi_int_count++;
-               FIQ_WRITE(state->mphi_regs.outdda, (int) state->dummy_send);
+               FIQ_WRITE(state->mphi_regs.outdda, state->dummy_send_dma);
                FIQ_WRITE(state->mphi_regs.outddb, (1<<29));
 
        }
@@ -1408,7 +1408,7 @@ void notrace dwc_otg_fiq_nop(struct fiq_state *state)
                FIQ_WRITE(state->dwc_regs_base + GINTMSK, gintmsk.d32);
                /* Force a clear before another dummy send */
                FIQ_WRITE(state->mphi_regs.intstat, (1<<29));
-               FIQ_WRITE(state->mphi_regs.outdda, (int) state->dummy_send);
+               FIQ_WRITE(state->mphi_regs.outdda, state->dummy_send_dma);
                FIQ_WRITE(state->mphi_regs.outddb, (1<<29));
 
        }

diff --git a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
index 06288ec..f517371 100644 (file)
--- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
+++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
@@ -352,6 +352,7 @@ struct fiq_state {
        dma_addr_t dma_base;
        struct fiq_dma_blob *fiq_dmab;
        void *dummy_send;
+       dma_addr_t dummy_send_dma;
        gintmsk_data_t gintmsk_saved;
        haintmsk_data_t haintmsk_saved;
        int mphi_int_count;

diff --git a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
index 5051008..855afd2 100644 (file)
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
@@ -929,6 +929,8 @@ static void dwc_otg_hcd_free(dwc_otg_hcd_t * dwc_otg_hcd)
        DWC_TIMER_FREE(dwc_otg_hcd->conn_timer);
        DWC_TASK_FREE(dwc_otg_hcd->reset_tasklet);
        DWC_TASK_FREE(dwc_otg_hcd->completion_tasklet);
+       DWC_DMA_FREE(dev, 16, dwc_otg_hcd->fiq_state->dummy_send,
+                    dwc_otg_hcd->fiq_state->dummy_send_dma);
        DWC_FREE(dwc_otg_hcd->fiq_state);
 
 #ifdef DWC_DEV_SRPCAP
@@ -1021,7 +1023,8 @@ int dwc_otg_hcd_init(dwc_otg_hcd_t * hcd, dwc_otg_core_if_t * core_if)
                for (i = 0; i < num_channels; i++) {
                        hcd->fiq_state->channel[i].fsm = FIQ_PASSTHROUGH;
                }
-               hcd->fiq_state->dummy_send = DWC_ALLOC_ATOMIC(16);
+               hcd->fiq_state->dummy_send = DWC_DMA_ALLOC_ATOMIC(dev, 16,
+                                                        &hcd->fiq_state->dummy_send_dma);
 
                hcd->fiq_stack = DWC_ALLOC(sizeof(struct fiq_stack));
                if (!hcd->fiq_stack) {