git: aa399ad3e554 - stable/13 - bcm_dma: don't dereference NULL softc

The branch stable/13 has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=aa399ad3e554223b8bf741c3933c38dec92eaf20

commit aa399ad3e554223b8bf741c3933c38dec92eaf20
Author:     Mitchell Horne <mhorne@FreeBSD.org>
AuthorDate: 2023-02-24 17:19:54 +0000
Commit:     Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2023-03-07 16:55:01 +0000

    bcm_dma: don't dereference NULL softc
    
    This file defines a small API to be used by other drivers. If any of
    these functions are called before the bcm_dma device has attached we
    should handle the error gracefully. Fix a formatting quirk while here.
    
    Reviewed by:    manu
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D38756
    
    (cherry picked from commit 07ccf71451d7377b1a6f3367f738ce7ddb1f2a24)
---
 sys/arm/broadcom/bcm2835/bcm2835_dma.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/sys/arm/broadcom/bcm2835/bcm2835_dma.c b/sys/arm/broadcom/bcm2835/bcm2835_dma.c
index af86647704f6..f596303959da 100644
--- a/sys/arm/broadcom/bcm2835/bcm2835_dma.c
+++ b/sys/arm/broadcom/bcm2835/bcm2835_dma.c
@@ -328,6 +328,9 @@ bcm_dma_allocate(int req_ch)
 	int ch = BCM_DMA_CH_INVALID;
 	int i;
 
+	if (sc == NULL)
+		return (BCM_DMA_CH_INVALID);
+
 	if (req_ch >= BCM_DMA_CH_MAX)
 		return (BCM_DMA_CH_INVALID);
 
@@ -343,13 +346,10 @@ bcm_dma_allocate(int req_ch)
 				break;
 			}
 		}
-	}
-	else {
-		if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
-			ch = req_ch;
-			sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
-			sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
-		}
+	} else if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
+		ch = req_ch;
+		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
+		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
 	}
 
 	mtx_unlock(&sc->sc_mtx);
@@ -364,6 +364,9 @@ bcm_dma_free(int ch)
 {
 	struct bcm_dma_softc *sc = bcm_dma_sc;
 
+	if (sc == NULL)
+		return (-1);
+
 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
 		return (-1);
 
@@ -392,6 +395,9 @@ bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
 	struct bcm_dma_softc *sc = bcm_dma_sc;
 	struct bcm_dma_cb *cb;
 
+	if (sc == NULL)
+		return (-1);
+
 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
 		return (-1);
 
@@ -531,6 +537,9 @@ bcm_dma_reg_dump(int ch)
 	int i;
 	uint32_t reg;
 
+	if (sc == NULL)
+		return;
+
 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
 		return;
 
@@ -558,6 +567,9 @@ bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
 	struct bcm_dma_softc *sc = bcm_dma_sc;
 	struct bcm_dma_cb *cb;
 
+	if (sc == NULL)
+		return (-1);
+
 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
 		return (-1);
 
@@ -597,6 +609,9 @@ bcm_dma_length(int ch)
 	struct bcm_dma_softc *sc = bcm_dma_sc;
 	struct bcm_dma_cb *cb;
 
+	if (sc == NULL)
+		return (0);
+
 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
 		return (0);