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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 18/21] xen/arm: Allow vpl011 to be used by DomU
Make vpl011 being able to be used without a userspace component in Dom0.
In that case, output is printed to the Xen serial and input is received
from the Xen serial one character at a time.
Call domain_vpl011_init during construct_domU if vpl011 is enabled.
Introduce a new ring struct with only the ring array to avoid a waste of
memory. Introduce separate read_date and write_data functions for
initial domains: vpl011_write_data_noring is very simple and just writes
to the console, while vpl011_read_data_inring is a duplicate of
vpl011_read_data. Although textually almost identical, we are forced to
duplicate the functions because the struct layout is different.
Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
---
Changes in v2:
- only init if vpl011
- rename vpl011_read_char to vpl011_rx_char
- remove spurious change
- fix coding style
- use different ring struct
- move the write_data changes to their own function
(vpl011_write_data_noring)
- duplicate vpl011_read_data
---
xen/arch/arm/domain_build.c | 10 ++-
xen/arch/arm/vpl011.c | 185 ++++++++++++++++++++++++++++++++++++++-----
xen/include/asm-arm/vpl011.h | 10 +++
3 files changed, 182 insertions(+), 23 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 718be48..d7e9040 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2531,7 +2531,15 @@ static int __init construct_domU(struct domain *d,
struct dt_device_node *node)
if ( rc < 0 )
return rc;
- return __construct_domain(d, &kinfo);
+ rc = __construct_domain(d, &kinfo);
+ if ( rc < 0 )
+ return rc;
+
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+ if ( vpl011 )
+ rc = domain_vpl011_init(d, NULL);
+#endif
+ return rc;
}
int __init construct_dom0(struct domain *d)
diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
index e75957f..d4aab64 100644
--- a/xen/arch/arm/vpl011.c
+++ b/xen/arch/arm/vpl011.c
@@ -83,6 +83,111 @@ static void vpl011_update_interrupt_status(struct domain *d)
#endif
}
+void vpl011_rx_char(struct domain *d, char c)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct xencons_in *intf = vpl011->inring;
+ XENCONS_RING_IDX in_cons, in_prod, in_fifo_level;
+
+ VPL011_LOCK(d, flags);
+
+ in_cons = intf->in_cons;
+ in_prod = intf->in_prod;
+ if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) ==
sizeof(intf->in) )
+ {
+ VPL011_UNLOCK(d, flags);
+ return;
+ }
+
+ intf->in[xencons_mask(in_prod, sizeof(intf->in))] = c;
+ intf->in_prod = in_prod + 1;
+
+ in_fifo_level = xencons_queued(in_prod,
+ in_cons,
+ sizeof(intf->in));
+
+ vpl011_data_avail(d, in_fifo_level, sizeof(intf->in), 0, 1024);
+ VPL011_UNLOCK(d, flags);
+}
+
+static void vpl011_write_data_noring(struct domain *d, uint8_t data)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+
+ VPL011_LOCK(d, flags);
+
+ printk("%c", data);
+ if (data == '\n')
+ printk("DOM%u: ", d->domain_id);
+
+ vpl011->uartris |= TXI;
+ vpl011->uartfr &= ~TXFE;
+ vpl011_update_interrupt_status(d);
+
+ VPL011_UNLOCK(d, flags);
+}
+
+static uint8_t vpl011_read_data_inring(struct domain *d)
+{
+ unsigned long flags;
+ uint8_t data = 0;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct xencons_in *intf = vpl011->inring;
+ XENCONS_RING_IDX in_cons, in_prod;
+
+ VPL011_LOCK(d, flags);
+
+ in_cons = intf->in_cons;
+ in_prod = intf->in_prod;
+
+ smp_rmb();
+
+ /*
+ * It is expected that there will be data in the ring buffer when this
+ * function is called since the guest is expected to read the data register
+ * only if the TXFE flag is not set.
+ * If the guest still does read when TXFE bit is set then 0 will be
returned.
+ */
+ if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) > 0 )
+ {
+ unsigned int fifo_level;
+
+ data = intf->in[xencons_mask(in_cons, sizeof(intf->in))];
+ in_cons += 1;
+ smp_mb();
+ intf->in_cons = in_cons;
+
+ fifo_level = xencons_queued(in_prod, in_cons, sizeof(intf->in));
+
+ /* If the FIFO is now empty, we clear the receive timeout interrupt. */
+ if ( fifo_level == 0 )
+ {
+ vpl011->uartfr |= RXFE;
+ vpl011->uartris &= ~RTI;
+ }
+
+ /* If the FIFO is more than half empty, we clear the RX interrupt. */
+ if ( fifo_level < sizeof(intf->in) - SBSA_UART_FIFO_LEVEL )
+ vpl011->uartris &= ~RXI;
+
+ vpl011_update_interrupt_status(d);
+ }
+ else
+ gprintk(XENLOG_ERR, "vpl011: Unexpected IN ring buffer empty\n");
+
+ /*
+ * We have consumed a character or the FIFO was empty, so clear the
+ * "FIFO full" bit.
+ */
+ vpl011->uartfr &= ~RXFF;
+
+ VPL011_UNLOCK(d, flags);
+
+ return data;
+}
+
static uint8_t vpl011_read_data(struct domain *d)
{
unsigned long flags;
@@ -246,7 +351,10 @@ static int vpl011_mmio_read(struct vcpu *v,
case DR:
if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
- *r = vreg_reg32_extract(vpl011_read_data(d), info);
+ if ( vpl011->ring_enable )
+ *r = vreg_reg32_extract(vpl011_read_data(d), info);
+ else
+ *r = vreg_reg32_extract(vpl011_read_data_inring(d), info);
return 1;
case RSR:
@@ -331,7 +439,10 @@ static int vpl011_mmio_write(struct vcpu *v,
vreg_reg32_update(&data, r, info);
data &= 0xFF;
- vpl011_write_data(v->domain, data);
+ if ( vpl011->ring_enable )
+ vpl011_write_data(v->domain, data);
+ else
+ vpl011_write_data_noring(v->domain, data);
return 1;
}
@@ -476,27 +587,47 @@ int domain_vpl011_init(struct domain *d, struct
vpl011_init_info *info)
if ( vpl011->ring.ring_buf )
return -EINVAL;
- /* Map the guest PFN to Xen address space. */
- rc = prepare_ring_for_helper(d,
- gfn_x(info->gfn),
- &vpl011->ring.ring_page,
- &vpl011->ring.ring_buf);
- if ( rc < 0 )
- goto out;
+ /*
+ * info is NULL for domUs started by Xen at boot time, with no
+ * corresponding userspace component in dom0
+ */
+ if ( info != NULL )
+ {
+ vpl011->ring_enable = true;
+
+ /* Map the guest PFN to Xen address space. */
+ rc = prepare_ring_for_helper(d,
+ gfn_x(info->gfn),
+ &vpl011->ring.ring_page,
+ &vpl011->ring.ring_buf);
+ if ( rc < 0 )
+ goto out;
+
+ rc = alloc_unbound_xen_event_channel(d, 0, info->console_domid,
+ vpl011_notification);
+ if ( rc < 0 )
+ goto out1;
+
+ vpl011->evtchn = info->evtchn = rc;
+ }
+ else
+ {
+ vpl011->ring_enable = false;
+
+ vpl011->inring = xzalloc(struct xencons_in);
+ if ( vpl011->inring == NULL )
+ {
+ rc = -EINVAL;
+ goto out1;
+ }
+ }
rc = vgic_reserve_virq(d, GUEST_VPL011_SPI);
if ( !rc )
{
rc = -EINVAL;
- goto out1;
- }
-
- rc = alloc_unbound_xen_event_channel(d, 0, info->console_domid,
- vpl011_notification);
- if ( rc < 0 )
goto out2;
-
- vpl011->evtchn = info->evtchn = rc;
+ }
spin_lock_init(&vpl011->lock);
@@ -509,7 +640,10 @@ out2:
vgic_free_virq(d, GUEST_VPL011_SPI);
out1:
- destroy_ring_for_helper(&vpl011->ring.ring_buf, vpl011->ring.ring_page);
+ if ( vpl011->ring_enable )
+ destroy_ring_for_helper(&vpl011->ring.ring_buf,
vpl011->ring.ring_page);
+ else
+ xfree(vpl011->inring);
out:
return rc;
@@ -519,11 +653,18 @@ void domain_vpl011_deinit(struct domain *d)
{
struct vpl011 *vpl011 = &d->arch.vpl011;
- if ( !vpl011->ring.ring_buf )
- return;
+ if ( vpl011->ring_enable )
+ {
+ if ( !vpl011->ring.ring_buf )
+ return;
- free_xen_event_channel(d, vpl011->evtchn);
- destroy_ring_for_helper(&vpl011->ring.ring_buf, vpl011->ring.ring_page);
+ free_xen_event_channel(d, vpl011->evtchn);
+ destroy_ring_for_helper(&vpl011->ring.ring_buf,
vpl011->ring.ring_page);
+ }
+ else
+ {
+ xfree(vpl011->inring);
+ }
}
/*
diff --git a/xen/include/asm-arm/vpl011.h b/xen/include/asm-arm/vpl011.h
index c3d375b..be43abf 100644
--- a/xen/include/asm-arm/vpl011.h
+++ b/xen/include/asm-arm/vpl011.h
@@ -21,6 +21,7 @@
#include <public/domctl.h>
#include <public/io/ring.h>
+#include <public/io/console.h>
#include <asm/vreg.h>
#include <xen/mm.h>
@@ -30,12 +31,19 @@
#define SBSA_UART_FIFO_SIZE 32
+struct xencons_in {
+ char in[1024];
+ XENCONS_RING_IDX in_cons, in_prod;
+};
+
struct vpl011 {
+ bool ring_enable;
union {
struct {
void *ring_buf;
struct page_info *ring_page;
} ring;
+ struct xencons_in *inring;
};
uint32_t uartfr; /* Flag register */
uint32_t uartcr; /* Control register */
@@ -57,6 +65,7 @@ struct vpl011_init_info {
int domain_vpl011_init(struct domain *d,
struct vpl011_init_info *info);
void domain_vpl011_deinit(struct domain *d);
+void vpl011_rx_char(struct domain *d, char c);
#else
static inline int domain_vpl011_init(struct domain *d,
struct vpl011_init_info *info)
@@ -65,6 +74,7 @@ static inline int domain_vpl011_init(struct domain *d,
}
static inline void domain_vpl011_deinit(struct domain *d) { }
+static inline void vpl011_rx_char(struct domain *d, char c) { }
#endif
#endif /* _VPL011_H_ */
--
1.9.1
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