Add another work ring buffer for received data, and point IN TRB at it.
Ensure there is always at least one pending IN TRB, so the controller
has a way to send incoming data to the driver.
Note that both "success" and "short packet" completion codes are okay -
in fact it will be "short packet" most of the time, as the TRB length is
about maximum size, not required size.
Signed-off-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeul...@suse.com>
---
Changes in v4:
- adjust return types
- add some const
New patch in v3
---
docs/misc/xen-command-line.pandoc | 6 +-
xen/drivers/char/xhci-dbc.c | 129 +++++++++++++++++++++++++++++++-
2 files changed, 132 insertions(+), 3 deletions(-)
diff --git a/docs/misc/xen-command-line.pandoc
b/docs/misc/xen-command-line.pandoc
index f6bdae9ca5f4..fb4d80c590f3 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -731,9 +731,9 @@ Available alternatives, with their meaning, are:
Specify the USB controller to use, either by instance number (when going
over the PCI busses sequentially) or by PCI device (must be on segment 0).
-Use `ehci` for EHCI debug port, use `xhci` for XHCI debug capability (output
-only). XHCI driver will wait indefinitely for the debug host to connect - make
-sure the cable is connected.
+Use `ehci` for EHCI debug port, use `xhci` for XHCI debug capability.
+XHCI driver will wait indefinitely for the debug host to connect - make sure
+the cable is connected.
### debug_stack_lines
> `= <integer>`
diff --git a/xen/drivers/char/xhci-dbc.c b/xen/drivers/char/xhci-dbc.c
index fc9745f7c2ac..557c5fc785ce 100644
--- a/xen/drivers/char/xhci-dbc.c
+++ b/xen/drivers/char/xhci-dbc.c
@@ -111,6 +111,7 @@ enum {
enum {
XHCI_TRB_CC_SUCCESS = 1,
XHCI_TRB_CC_TRB_ERR = 5,
+ XHCI_TRB_CC_SHORT_PACKET = 13,
};
/* DbC endpoint types */
@@ -239,6 +240,7 @@ struct dbc {
struct xhci_trb_ring dbc_oring;
struct xhci_trb_ring dbc_iring;
struct dbc_work_ring dbc_owork;
+ struct dbc_work_ring dbc_iwork;
struct xhci_string_descriptor *dbc_str;
pci_sbdf_t sbdf;
@@ -444,6 +446,16 @@ static void xhci_trb_norm_set_ioc(struct xhci_trb *trb)
trb->ctrl |= 0x20;
}
+static uint64_t xhci_trb_norm_buf(const struct xhci_trb *trb)
+{
+ return trb->params;
+}
+
+static uint32_t xhci_trb_norm_len(const struct xhci_trb *trb)
+{
+ return trb->status & 0x1FFFF;
+}
+
/**
* Fields for Transfer Event TRBs (see section 6.4.2.1). Note that event
* TRBs are read-only from software
@@ -453,6 +465,17 @@ static uint64_t xhci_trb_tfre_ptr(const struct xhci_trb
*trb)
return trb->params;
}
+static uint32_t xhci_trb_tfre_cc(const struct xhci_trb *trb)
+{
+ return trb->status >> 24;
+}
+
+/* Amount of data _not_ transferred */
+static uint32_t xhci_trb_tfre_len(const struct xhci_trb *trb)
+{
+ return trb->status & 0x1FFFF;
+}
+
/* Fields for link TRBs (section 6.4.4.1) */
static void xhci_trb_link_set_rsp(struct xhci_trb *trb, uint64_t rsp)
{
@@ -494,6 +517,14 @@ static bool xhci_trb_ring_full(const struct xhci_trb_ring
*ring)
return ((ring->enq + 1) & (DBC_TRB_RING_CAP - 1)) == ring->deq;
}
+static unsigned int xhci_trb_ring_size(const struct xhci_trb_ring *ring)
+{
+ if ( ring->enq >= ring->deq )
+ return ring->enq - ring->deq;
+
+ return DBC_TRB_RING_CAP - ring->deq + ring->enq;
+}
+
static bool dbc_work_ring_full(const struct dbc_work_ring *ring)
{
return ((ring->enq + 1) & (DBC_WORK_RING_CAP - 1)) == ring->deq;
@@ -507,6 +538,14 @@ static unsigned int dbc_work_ring_size(const struct
dbc_work_ring *ring)
return DBC_WORK_RING_CAP - ring->deq + ring->enq;
}
+static unsigned int dbc_work_ring_space_to_end(const struct dbc_work_ring
*ring)
+{
+ if ( ring->enq >= ring->deq )
+ return DBC_WORK_RING_CAP - ring->enq;
+
+ return ring->deq - ring->enq;
+}
+
static void dbc_push_trb(struct dbc *dbc, struct xhci_trb_ring *ring,
uint64_t dma, uint64_t len)
{
@@ -567,6 +606,31 @@ static unsigned int dbc_push_work(struct dbc *dbc, struct
dbc_work_ring *ring,
return i;
}
+static void dbc_rx_trb(struct dbc *dbc, struct xhci_trb *trb,
+ uint64_t not_transferred)
+{
+ struct dbc_work_ring *ring = &dbc->dbc_iwork;
+ unsigned int rx_len;
+ unsigned int end, start = ring->enq;
+
+ if ( xhci_trb_type(trb) != XHCI_TRB_NORM )
+ /* Can be Link TRB for example. */
+ return;
+
+ ASSERT(xhci_trb_norm_buf(trb) == ring->dma + ring->enq);
+ ASSERT(xhci_trb_norm_len(trb) >= not_transferred);
+ rx_len = xhci_trb_norm_len(trb) - not_transferred;
+
+ /* It can hit the ring end, but should not wrap around. */
+ ASSERT(ring->enq + rx_len <= DBC_WORK_RING_CAP);
+ ring->enq = (ring->enq + rx_len) & (DBC_WORK_RING_CAP - 1);
+
+ end = ring->enq;
+
+ if ( end > start )
+ cache_flush(&ring->buf[start], end - start);
+}
+
/*
* Note that if IN transfer support is added, then this
* will need to be changed; it assumes an OUT transfer ring only
@@ -576,6 +640,7 @@ static void dbc_pop_events(struct dbc *dbc)
struct dbc_reg *reg = dbc->dbc_reg;
struct xhci_trb_ring *er = &dbc->dbc_ering;
struct xhci_trb_ring *tr = &dbc->dbc_oring;
+ struct xhci_trb_ring *ir = &dbc->dbc_iring;
struct xhci_trb *event = &er->trb[er->deq];
uint64_t erdp = readq(®->erdp);
uint32_t portsc;
@@ -601,6 +666,14 @@ static void dbc_pop_events(struct dbc *dbc)
trb_idx = (event_ptr - tr->dma) >> XHCI_TRB_SHIFT;
tr->deq = (trb_idx + 1) & (DBC_TRB_RING_CAP - 1);
}
+ else if ( event_ptr - ir->dma < DBC_TRB_RING_BYTES )
+ {
+ trb_idx = (event_ptr - ir->dma) >> XHCI_TRB_SHIFT;
+ if ( xhci_trb_tfre_cc(event) == XHCI_TRB_CC_SUCCESS ||
+ xhci_trb_tfre_cc(event) == XHCI_TRB_CC_SHORT_PACKET )
+ dbc_rx_trb(dbc, &ir->trb[trb_idx],
xhci_trb_tfre_len(event));
+ ir->deq = (trb_idx + 1) & (DBC_TRB_RING_CAP - 1);
+ }
else
dbc_alert("event: TRB 0x%lx not found in any ring\n",
event_ptr);
@@ -871,6 +944,7 @@ static bool __init dbc_open(struct dbc *dbc)
return false;
dbc_init_work_ring(dbc, &dbc->dbc_owork);
+ dbc_init_work_ring(dbc, &dbc->dbc_iwork);
dbc_enable_dbc(dbc);
dbc->open = true;
@@ -947,6 +1021,33 @@ static void dbc_flush(struct dbc *dbc, struct
xhci_trb_ring *trb,
}
/**
+ * Ensure DbC has a pending transfer TRB to receive data into.
+ *
+ * @param dbc the dbc to flush
+ * @param trb the ring for the TRBs to transfer
+ * @param wrk the work ring to receive data into
+ */
+static void dbc_enqueue_in(struct dbc *dbc, struct xhci_trb_ring *trb,
+ struct dbc_work_ring *wrk)
+{
+ struct dbc_reg *reg = dbc->dbc_reg;
+ uint32_t db = (readl(®->db) & 0xFFFF00FF) | (trb->db << 8);
+
+ /* Check if there is already queued TRB */
+ if ( xhci_trb_ring_size(trb) >= 1 )
+ return;
+
+ if ( dbc_work_ring_full(wrk) )
+ return;
+
+ dbc_push_trb(dbc, trb, wrk->dma + wrk->enq,
+ dbc_work_ring_space_to_end(wrk));
+
+ wmb();
+ writel(db, ®->db);
+}
+
+/**
* Queue a single character to the DbC. A transfer TRB will be created
* if the character is a newline and the DbC will be notified that data is
* available for writing to the debug host.
@@ -969,6 +1070,19 @@ static int64_t dbc_putc(struct dbc *dbc, char c)
return 1;
}
+static int dbc_getc(struct dbc *dbc, char *c)
+{
+ struct dbc_work_ring *wrk = &dbc->dbc_iwork;
+
+ if ( dbc_work_ring_size(wrk) == 0 )
+ return 0;
+
+ *c = wrk->buf[wrk->deq];
+ wrk->deq = (wrk->deq + 1) & (DBC_WORK_RING_CAP - 1);
+
+ return 1;
+}
+
struct dbc_uart {
struct dbc dbc;
struct timer timer;
@@ -987,10 +1101,16 @@ static void cf_check dbc_uart_poll(void *data)
if ( spin_trylock_irqsave(&port->tx_lock, flags) )
{
if ( dbc_ensure_running(dbc) )
+ {
dbc_flush(dbc, &dbc->dbc_oring, &dbc->dbc_owork);
+ dbc_enqueue_in(dbc, &dbc->dbc_iring, &dbc->dbc_iwork);
+ }
spin_unlock_irqrestore(&port->tx_lock, flags);
}
+ while ( dbc_work_ring_size(&dbc->dbc_iwork) )
+ serial_rx_interrupt(port, guest_cpu_user_regs());
+
serial_tx_interrupt(port, guest_cpu_user_regs());
set_timer(&uart->timer, NOW() + MICROSECS(DBC_POLL_INTERVAL));
}
@@ -1029,6 +1149,12 @@ static void cf_check dbc_uart_putc(struct serial_port
*port, char c)
dbc_putc(&uart->dbc, c);
}
+static int cf_check dbc_uart_getc(struct serial_port *port, char *c)
+{
+ struct dbc_uart *uart = port->uart;
+ return dbc_getc(&uart->dbc, c);
+}
+
static void cf_check dbc_uart_flush(struct serial_port *port)
{
s_time_t goal;
@@ -1048,6 +1174,7 @@ static struct uart_driver dbc_uart_driver = {
.init_postirq = dbc_uart_init_postirq,
.tx_ready = dbc_uart_tx_ready,
.putc = dbc_uart_putc,
+ .getc = dbc_uart_getc,
.flush = dbc_uart_flush,
};
@@ -1057,6 +1184,7 @@ struct dbc_dma_bufs {
struct xhci_trb out_trb[DBC_TRB_RING_CAP];
struct xhci_trb in_trb[DBC_TRB_RING_CAP];
uint8_t out_wrk_buf[DBC_WORK_RING_CAP];
+ uint8_t in_wrk_buf[DBC_WORK_RING_CAP];
struct xhci_erst_segment erst __aligned(16);
struct xhci_dbc_ctx ctx __aligned(16);
struct xhci_string_descriptor str_buf[DBC_STRINGS_COUNT];
@@ -1118,6 +1246,7 @@ void __init xhci_dbc_uart_init(void)
dbc->dbc_oring.trb = dbc_dma_bufs.out_trb;
dbc->dbc_iring.trb = dbc_dma_bufs.in_trb;
dbc->dbc_owork.buf = dbc_dma_bufs.out_wrk_buf;
+ dbc->dbc_iwork.buf = dbc_dma_bufs.in_wrk_buf;
dbc->dbc_str = dbc_dma_bufs.str_buf;
if ( dbc_open(dbc) )
--
git-series 0.9.1
