Re: [PATCH] hw/net/allwinner-sun8i-emac: Use AddressSpace for DMA transf

On Fri, Aug 14, 2020 at 2:29 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:

Allow the device to execute the DMA transfers in a different
AddressSpace.

The H3 SoC keeps using the system_memory address space,
but via the proper dma_memory_access() API.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Tested with:
AVOCADO_ALLOW_LARGE_STORAGE=1 avocado run -t machine:orangepi-pc tests/acceptance/
---
include/hw/net/allwinner-sun8i-emac.h | 6 ++++
hw/arm/allwinner-h3.c | 2 ++
hw/net/allwinner-sun8i-emac.c | 46 +++++++++++++++++----------
3 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/include/hw/net/allwinner-sun8i-emac.h b/include/hw/net/allwinner-sun8i-emac.h
index eda034e96b..dd1d7b96cd 100644
--- a/include/hw/net/allwinner-sun8i-emac.h
+++ b/include/hw/net/allwinner-sun8i-emac.h
@@ -49,6 +49,12 @@ typedef struct AwSun8iEmacState {
/** Interrupt output signal to notify CPU */
qemu_irq irq;

+ /** Memory region where DMA transfers are done */
+ MemoryRegion *dma_mr;
+
+ /** Address space used internally for DMA transfers */
+ AddressSpace dma_as;
+
/** Generic Network Interface Controller (NIC) for networking API */
NICState *nic;

diff --git a/hw/arm/allwinner-h3.c b/hw/arm/allwinner-h3.c
index ff92ded82c..21a5d759d1 100644
--- a/hw/arm/allwinner-h3.c
+++ b/hw/arm/allwinner-h3.c
@@ -363,6 +363,8 @@ static void allwinner_h3_realize(DeviceState *dev, Error **errp)
qemu_check_nic_model(&nd_table[0], TYPE_AW_SUN8I_EMAC);
qdev_set_nic_properties(DEVICE(&s->emac), &nd_table[0]);
}
+ object_property_set_link(OBJECT(&s->emac), "dma-memory",
+ OBJECT(get_system_memory()), &error_fatal);
sysbus_realize(SYS_BUS_DEVICE(&s->emac), &error_fatal);
sysbus_mmio_map(SYS_BUS_DEVICE(&s->emac), 0, s->memmap[AW_H3_EMAC]);
sysbus_connect_irq(SYS_BUS_DEVICE(&s->emac), 0,
diff --git a/hw/net/allwinner-sun8i-emac.c b/hw/net/allwinner-sun8i-emac.c
index 28637ff4c1..38d328587e 100644
--- a/hw/net/allwinner-sun8i-emac.c
+++ b/hw/net/allwinner-sun8i-emac.c
@@ -19,6 +19,7 @@

#include "qemu/osdep.h"
#include "qemu/units.h"
+#include "qapi/error.h"
#include "hw/sysbus.h"
#include "migration/vmstate.h"
#include "net/net.h"
@@ -29,6 +30,7 @@
#include "net/checksum.h"
#include "qemu/module.h"
#include "exec/cpu-common.h"
+#include "sysemu/dma.h"
#include "hw/net/allwinner-sun8i-emac.h"

/* EMAC register offsets */
@@ -337,12 +339,13 @@ static void allwinner_sun8i_emac_update_irq(AwSun8iEmacState *s)
qemu_set_irq(s->irq, (s->int_sta & s->int_en) != 0);
}

-static uint32_t allwinner_sun8i_emac_next_desc(FrameDescriptor *desc,
+static uint32_t allwinner_sun8i_emac_next_desc(AwSun8iEmacState *s,
+ FrameDescriptor *desc,
size_t min_size)
{
uint32_t paddr = desc->next;

- cpu_physical_memory_read(paddr, desc, sizeof(*desc));
+ dma_memory_read(&s->dma_as, paddr, desc, sizeof(*desc));

if ((desc->status & DESC_STATUS_CTL) &&
(desc->status2 & DESC_STATUS2_BUF_SIZE_MASK) >= min_size) {
@@ -352,7 +355,8 @@ static uint32_t allwinner_sun8i_emac_next_desc(FrameDescriptor *desc,
}
}

-static uint32_t allwinner_sun8i_emac_get_desc(FrameDescriptor *desc,
+static uint32_t allwinner_sun8i_emac_get_desc(AwSun8iEmacState *s,
+ FrameDescriptor *desc,
uint32_t start_addr,
size_t min_size)
{
@@ -360,7 +364,7 @@ static uint32_t allwinner_sun8i_emac_get_desc(FrameDescriptor *desc,

/* Note that the list is a cycle. Last entry points back to the head. */
while (desc_addr != 0) {
- cpu_physical_memory_read(desc_addr, desc, sizeof(*desc));
+ dma_memory_read(&s->dma_as, desc_addr, desc, sizeof(*desc));

if ((desc->status & DESC_STATUS_CTL) &&
(desc->status2 & DESC_STATUS2_BUF_SIZE_MASK) >= min_size) {
@@ -379,20 +383,21 @@ static uint32_t allwinner_sun8i_emac_rx_desc(AwSun8iEmacState *s,
FrameDescriptor *desc,
size_t min_size)
{
- return allwinner_sun8i_emac_get_desc(desc, s->rx_desc_curr, min_size);
+ return allwinner_sun8i_emac_get_desc(s, desc, s->rx_desc_curr, min_size);
}

static uint32_t allwinner_sun8i_emac_tx_desc(AwSun8iEmacState *s,
FrameDescriptor *desc,
size_t min_size)
{
- return allwinner_sun8i_emac_get_desc(desc, s->tx_desc_head, min_size);
+ return allwinner_sun8i_emac_get_desc(s, desc, s->tx_desc_head, min_size);
}

-static void allwinner_sun8i_emac_flush_desc(FrameDescriptor *desc,
+static void allwinner_sun8i_emac_flush_desc(AwSun8iEmacState *s,
+ FrameDescriptor *desc,
uint32_t phys_addr)
{
- cpu_physical_memory_write(phys_addr, desc, sizeof(*desc));
+ dma_memory_write(&s->dma_as, phys_addr, desc, sizeof(*desc));
}

static bool allwinner_sun8i_emac_can_receive(NetClientState *nc)
@@ -450,8 +455,8 @@ static ssize_t allwinner_sun8i_emac_receive(NetClientState *nc,
<< RX_DESC_STATUS_FRM_LEN_SHIFT;
}

- cpu_physical_memory_write(desc.addr, buf, desc_bytes);
- allwinner_sun8i_emac_flush_desc(&desc, s->rx_desc_curr);
+ dma_memory_write(&s->dma_as, desc.addr, buf, desc_bytes);
+ allwinner_sun8i_emac_flush_desc(s, &desc, s->rx_desc_curr);
trace_allwinner_sun8i_emac_receive(s->rx_desc_curr, desc.addr,
desc_bytes);

@@ -465,7 +470,7 @@ static ssize_t allwinner_sun8i_emac_receive(NetClientState *nc,
bytes_left -= desc_bytes;

/* Move to the next descriptor */
- s->rx_desc_curr = allwinner_sun8i_emac_next_desc(&desc, 64);
+ s->rx_desc_curr = allwinner_sun8i_emac_next_desc(s, &desc, 64);
if (!s->rx_desc_curr) {
/* Not enough buffer space available */
s->int_sta |= INT_STA_RX_BUF_UA;
@@ -501,10 +506,10 @@ static void allwinner_sun8i_emac_transmit(AwSun8iEmacState *s)
desc.status |= TX_DESC_STATUS_LENGTH_ERR;
break;
}
- cpu_physical_memory_read(desc.addr, packet_buf + packet_bytes, bytes);
+ dma_memory_read(&s->dma_as, desc.addr, packet_buf + packet_bytes, bytes);
packet_bytes += bytes;
desc.status &= ~DESC_STATUS_CTL;
- allwinner_sun8i_emac_flush_desc(&desc, s->tx_desc_curr);
+ allwinner_sun8i_emac_flush_desc(s, &desc, s->tx_desc_curr);

/* After the last descriptor, send the packet */
if (desc.status2 & TX_DESC_STATUS2_LAST_DESC) {
@@ -519,7 +524,7 @@ static void allwinner_sun8i_emac_transmit(AwSun8iEmacState *s)
packet_bytes = 0;
transmitted++;
}
- s->tx_desc_curr = allwinner_sun8i_emac_next_desc(&desc, 0);
+ s->tx_desc_curr = allwinner_sun8i_emac_next_desc(s, &desc, 0);
}

/* Raise transmit completed interrupt */
@@ -623,7 +628,7 @@ static uint64_t allwinner_sun8i_emac_read(void *opaque, hwaddr offset,
break;
case REG_TX_CUR_BUF: /* Transmit Current Buffer */
if (s->tx_desc_curr != 0) {
- cpu_physical_memory_read(s->tx_desc_curr, &desc, sizeof(desc));
+ dma_memory_read(&s->dma_as, s->tx_desc_curr, &desc, sizeof(desc));
value = desc.addr;
} else {
value = 0;
@@ -636,7 +641,7 @@ static uint64_t allwinner_sun8i_emac_read(void *opaque, hwaddr offset,
break;
case REG_RX_CUR_BUF: /* Receive Current Buffer */
if (s->rx_desc_curr != 0) {
- cpu_physical_memory_read(s->rx_desc_curr, &desc, sizeof(desc));
+ dma_memory_read(&s->dma_as, s->rx_desc_curr, &desc, sizeof(desc));
value = desc.addr;
} else {
value = 0;
@@ -790,6 +795,13 @@ static void allwinner_sun8i_emac_realize(DeviceState *dev, Error **errp)
{
AwSun8iEmacState *s = AW_SUN8I_EMAC(dev);

+ if (!s->dma_mr) {
+ error_setg(errp, TYPE_AW_SUN8I_EMAC " 'dma-memory' link not set");
+ return;
+ }
+
+ address_space_init(&s->dma_as, s->dma_mr, "emac-dma");
+
qemu_macaddr_default_if_unset(&s->conf.macaddr);
s->nic = qemu_new_nic(&net_allwinner_sun8i_emac_info, &s->conf,
object_get_typename(OBJECT(dev)), dev->id, s);
@@ -799,6 +811,8 @@ static void allwinner_sun8i_emac_realize(DeviceState *dev, Error **errp)
static Property allwinner_sun8i_emac_properties[] = {
DEFINE_NIC_PROPERTIES(AwSun8iEmacState, conf),
DEFINE_PROP_UINT8("phy-addr", AwSun8iEmacState, mii_phy_addr, 0),
+ DEFINE_PROP_LINK("dma-memory", AwSun8iEmacState, dma_mr,
+ TYPE_MEMORY_REGION, MemoryRegion *),
DEFINE_PROP_END_OF_LIST(),
};

--
2.21.3

From:	Niek Linnenbank
Subject:	Re: [PATCH] hw/net/allwinner-sun8i-emac: Use AddressSpace for DMA transfers
Date:	Mon, 17 Aug 2020 20:42:56 +0200