Author: skra
Date: Tue Feb 16 12:19:06 2016
New Revision: 295659
URL: https://svnweb.freebsd.org/changeset/base/295659
Log:
Do not use DMA channels used by GPU.
(1) The channel mask is get from "brcm,dma-channel-mask" property of
dma node, and if not provided, from "broadcom,channels" property.
(2) Consequently, sdhci driver does not allocate any specific channel.
(3) Use CS_RESET bit for initial channel reset.
Differential Revision: https://reviews.freebsd.org/D4303
Modified:
head/sys/arm/broadcom/bcm2835/bcm2835_dma.c
head/sys/arm/broadcom/bcm2835/bcm2835_dma.h
head/sys/arm/broadcom/bcm2835/bcm2835_sdhci.c
Modified: head/sys/arm/broadcom/bcm2835/bcm2835_dma.c
==============================================================================
--- head/sys/arm/broadcom/bcm2835/bcm2835_dma.c Tue Feb 16 11:51:54 2016
(r295658)
+++ head/sys/arm/broadcom/bcm2835/bcm2835_dma.c Tue Feb 16 12:19:06 2016
(r295659)
@@ -104,6 +104,15 @@ __FBSDID("$FreeBSD$");
/* relative offset from BCM_VC_DMA0_BASE (p.39) */
#define BCM_DMA_CH(n) (0x100*(n))
+/* channels used by GPU */
+#define BCM_DMA_CH_BULK 0
+#define BCM_DMA_CH_FAST1 2
+#define BCM_DMA_CH_FAST2 3
+
+#define BCM_DMA_CH_GPU_MASK ((1 << BCM_DMA_CH_BULK) | \
+ (1 << BCM_DMA_CH_FAST1) | \
+ (1 << BCM_DMA_CH_FAST2))
+
/* DMA Control Block - 256bit aligned (p.40) */
struct bcm_dma_cb {
uint32_t info; /* Transfer Information */
@@ -143,6 +152,7 @@ struct bcm_dma_softc {
};
static struct bcm_dma_softc *bcm_dma_sc = NULL;
+static uint32_t bcm_dma_channel_mask;
static void
bcm_dmamap_cb(void *arg, bus_dma_segment_t *segs,
@@ -205,16 +215,32 @@ static int
bcm_dma_init(device_t dev)
{
struct bcm_dma_softc *sc = device_get_softc(dev);
- uint32_t mask;
+ uint32_t reg;
struct bcm_dma_ch *ch;
void *cb_virt;
vm_paddr_t cb_phys;
int err;
int i;
- /* disable and clear interrupt status */
- bus_write_4(sc->sc_mem, BCM_DMA_ENABLE, 0);
- bus_write_4(sc->sc_mem, BCM_DMA_INT_STATUS, 0);
+ /*
+ * Only channels set in bcm_dma_channel_mask can be controlled by us.
+ * The others are out of our control as well as the corresponding bits
+ * in both BCM_DMA_ENABLE and BCM_DMA_INT_STATUS global registers. As
+ * these registers are RW ones, there is no safe way how to write only
+ * the bits which can be controlled by us.
+ *
+ * Fortunately, after reset, all channels are enabled in BCM_DMA_ENABLE
+ * register and all statuses are cleared in BCM_DMA_INT_STATUS one.
+ * Not touching these registers is a trade off between correct
+ * initialization which does not count on anything and not messing up
+ * something we have no control over.
+ */
+ reg = bus_read_4(sc->sc_mem, BCM_DMA_ENABLE);
+ if ((reg & bcm_dma_channel_mask) != bcm_dma_channel_mask)
+ device_printf(dev, "channels are not enabled\n");
+ reg = bus_read_4(sc->sc_mem, BCM_DMA_INT_STATUS);
+ if ((reg & bcm_dma_channel_mask) != 0)
+ device_printf(dev, "statuses are not cleared\n");
/* Allocate DMA chunks control blocks */
/* p.40 of spec - control block should be 32-bit aligned */
@@ -227,7 +253,7 @@ bcm_dma_init(device_t dev)
&sc->sc_dma_tag);
if (err) {
- device_printf(dev, "failed allocate DMA tag");
+ device_printf(dev, "failed allocate DMA tag\n");
return (err);
}
@@ -235,6 +261,13 @@ bcm_dma_init(device_t dev)
for (i = 0; i < BCM_DMA_CH_MAX; i++) {
ch = &sc->sc_dma_ch[i];
+ bzero(ch, sizeof(struct bcm_dma_ch));
+ ch->ch = i;
+ ch->flags = BCM_DMA_CH_UNMAP;
+
+ if ((bcm_dma_channel_mask & (1 << i)) == 0)
+ continue;
+
err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
&ch->dma_map);
@@ -263,33 +296,15 @@ bcm_dma_init(device_t dev)
break;
}
- bzero(ch, sizeof(struct bcm_dma_ch));
- ch->ch = i;
ch->cb = cb_virt;
ch->vc_cb = cb_phys;
- ch->intr_func = NULL;
- ch->intr_arg = NULL;
- ch->flags = BCM_DMA_CH_UNMAP;
-
+ ch->flags = BCM_DMA_CH_FREE;
ch->cb->info = INFO_WAIT_RESP;
/* reset DMA engine */
- bcm_dma_reset(dev, i);
+ bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
}
- /* now use DMA2/DMA3 only */
- sc->sc_dma_ch[2].flags = BCM_DMA_CH_FREE;
- sc->sc_dma_ch[3].flags = BCM_DMA_CH_FREE;
-
- /* enable DMAs */
- mask = 0;
-
- for (i = 0; i < BCM_DMA_CH_MAX; i++)
- if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE)
- mask |= (1 << i);
-
- bus_write_4(sc->sc_mem, BCM_DMA_ENABLE, mask);
-
return (0);
}
@@ -599,8 +614,11 @@ bcm_dma_intr(void *arg)
/* my interrupt? */
cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
- if (!(cs & (CS_INT | CS_ERR)))
+ if (!(cs & (CS_INT | CS_ERR))) {
+ device_printf(sc->sc_dev,
+ "unexpected DMA intr CH=%d, CS=%x\n", ch->ch, cs);
return;
+ }
/* running? */
if (!(ch->flags & BCM_DMA_CH_USED)) {
@@ -651,6 +669,7 @@ static int
bcm_dma_attach(device_t dev)
{
struct bcm_dma_softc *sc = device_get_softc(dev);
+ phandle_t node;
int rid, err = 0;
int i;
@@ -664,6 +683,19 @@ bcm_dma_attach(device_t dev)
sc->sc_intrhand[i] = NULL;
}
+ /* Get DMA channel mask. */
+ node = ofw_bus_get_node(sc->sc_dev);
+ if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
+ sizeof(bcm_dma_channel_mask)) == -1 &&
+ OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
+ sizeof(bcm_dma_channel_mask)) == -1) {
+ device_printf(dev, "could not get channel mask property\n");
+ return (ENXIO);
+ }
+
+ /* Mask out channels used by GPU. */
+ bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
+
/* DMA0 - DMA14 */
rid = 0;
sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
@@ -674,6 +706,9 @@ bcm_dma_attach(device_t dev)
/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
+ if ((bcm_dma_channel_mask & (1 << rid)) == 0)
+ continue;
+
sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
RF_ACTIVE);
if (sc->sc_irq[rid] == NULL) {
Modified: head/sys/arm/broadcom/bcm2835/bcm2835_dma.h
==============================================================================
--- head/sys/arm/broadcom/bcm2835/bcm2835_dma.h Tue Feb 16 11:51:54 2016
(r295658)
+++ head/sys/arm/broadcom/bcm2835/bcm2835_dma.h Tue Feb 16 12:19:06 2016
(r295659)
@@ -37,8 +37,6 @@
/* request CH for any nubmer */
#define BCM_DMA_CH_INVALID (-1)
#define BCM_DMA_CH_ANY (-1)
-#define BCM_DMA_CH_FAST1 (2)
-#define BCM_DMA_CH_FAST2 (3)
/* Peripheral DREQ Signals (4.2.1.3) */
#define BCM_DMA_DREQ_NONE 0
Modified: head/sys/arm/broadcom/bcm2835/bcm2835_sdhci.c
==============================================================================
--- head/sys/arm/broadcom/bcm2835/bcm2835_sdhci.c Tue Feb 16 11:51:54
2016 (r295658)
+++ head/sys/arm/broadcom/bcm2835/bcm2835_sdhci.c Tue Feb 16 12:19:06
2016 (r295659)
@@ -214,11 +214,7 @@ bcm_sdhci_attach(device_t dev)
sdhci_init_slot(dev, &sc->sc_slot, 0);
- sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_FAST1);
- if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
- sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_FAST2);
- if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
- sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_ANY);
+ sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_ANY);
if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
goto fail;
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