--- /dev/null
+/*
+ * arch/arm/vpl011.c
+ *
+ * Virtual PL011 UART
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/errno.h>
+#include <xen/event.h>
+#include <xen/guest_access.h>
+#include <xen/init.h>
+#include <xen/lib.h>
+#include <xen/mm.h>
+#include <xen/sched.h>
+#include <public/domctl.h>
+#include <public/io/console.h>
+#include <asm/pl011-uart.h>
+#include <asm/vgic-emul.h>
+#include <asm/vpl011.h>
+
+/*
+ * Since pl011 registers are 32-bit registers, all registers
+ * are handled similarly allowing 8-bit, 16-bit and 32-bit
+ * accesses except 64-bit access.
+ */
+static bool vpl011_reg32_check_access(struct hsr_dabt dabt)
+{
+ return (dabt.size != DABT_DOUBLE_WORD);
+}
+
+static void vpl011_update_interrupt_status(struct domain *d)
+{
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ uint32_t uartmis = vpl011->uartris & vpl011->uartimsc;
+
+ /*
+ * This function is expected to be called with the lock taken.
+ */
+ ASSERT(spin_is_locked(&vpl011->lock));
+
+ /*
+ * TODO: PL011 interrupts are level triggered which means
+ * that interrupt needs to be set/clear instead of being
+ * injected. However, currently vGIC does not handle level
+ * triggered interrupts properly. This function needs to be
+ * revisited once vGIC starts handling level triggered
+ * interrupts.
+ */
+
+ /*
+ * Raise an interrupt only if any additional interrupt
+ * status bit has been set since the last time.
+ */
+ if ( uartmis & ~vpl011->shadow_uartmis )
+ vgic_vcpu_inject_spi(d, GUEST_VPL011_SPI);
+
+ vpl011->shadow_uartmis = uartmis;
+}
+
+static uint8_t vpl011_read_data(struct domain *d)
+{
+ unsigned long flags;
+ uint8_t data = 0;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct xencons_interface *intf = vpl011->ring_buf;
+ 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 )
+ {
+ data = intf->in[xencons_mask(in_cons, sizeof(intf->in))];
+ in_cons += 1;
+ smp_mb();
+ intf->in_cons = in_cons;
+ }
+ else
+ gprintk(XENLOG_ERR, "vpl011: Unexpected IN ring buffer empty\n");
+
+ if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) == 0 )
+ {
+ vpl011->uartfr |= RXFE;
+ vpl011->uartris &= ~RXI;
+ }
+
+ vpl011->uartfr &= ~RXFF;
+
+ vpl011_update_interrupt_status(d);
+
+ VPL011_UNLOCK(d, flags);
+
+ /*
+ * Send an event to console backend to indicate that data has been
+ * read from the IN ring buffer.
+ */
+ notify_via_xen_event_channel(d, vpl011->evtchn);
+
+ return data;
+}
+
+static void vpl011_write_data(struct domain *d, uint8_t data)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct xencons_interface *intf = vpl011->ring_buf;
+ XENCONS_RING_IDX out_cons, out_prod;
+
+ VPL011_LOCK(d, flags);
+
+ out_cons = intf->out_cons;
+ out_prod = intf->out_prod;
+
+ smp_mb();
+
+ /*
+ * It is expected that the ring is not full when this function is called
+ * as the guest is expected to write to the data register only when the
+ * TXFF flag is not set.
+ * In case the guest does write even when the TXFF flag is set then the
+ * data will be silently dropped.
+ */
+ if ( xencons_queued(out_prod, out_cons, sizeof(intf->out)) !=
+ sizeof (intf->out) )
+ {
+ intf->out[xencons_mask(out_prod, sizeof(intf->out))] = data;
+ out_prod += 1;
+ smp_wmb();
+ intf->out_prod = out_prod;
+ }
+ else
+ gprintk(XENLOG_ERR, "vpl011: Unexpected OUT ring buffer full\n");
+
+ if ( xencons_queued(out_prod, out_cons, sizeof(intf->out)) ==
+ sizeof (intf->out) )
+ {
+ vpl011->uartfr |= TXFF;
+ vpl011->uartris &= ~TXI;
+ }
+
+ vpl011->uartfr |= BUSY;
+
+ vpl011->uartfr &= ~TXFE;
+
+ vpl011_update_interrupt_status(d);
+
+ VPL011_UNLOCK(d, flags);
+
+ /*
+ * Send an event to console backend to indicate that there is
+ * data in the OUT ring buffer.
+ */
+ notify_via_xen_event_channel(d, vpl011->evtchn);
+}
+
+static int vpl011_mmio_read(struct vcpu *v,
+ mmio_info_t *info,
+ register_t *r,
+ void *priv)
+{
+ struct hsr_dabt dabt = info->dabt;
+ uint32_t vpl011_reg = (uint32_t)(info->gpa - GUEST_PL011_BASE);
+ struct vpl011 *vpl011 = &v->domain->arch.vpl011;
+ struct domain *d = v->domain;
+ unsigned long flags;
+
+ switch ( vpl011_reg )
+ {
+ case DR:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ *r = vreg_reg32_extract(vpl011_read_data(d), info);
+ return 1;
+
+ case RSR:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ /* It always returns 0 as there are no physical errors. */
+ *r = 0;
+ return 1;
+
+ case FR:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ *r = vreg_reg32_extract(vpl011->uartfr, info);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ case RIS:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ *r = vreg_reg32_extract(vpl011->uartris, info);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ case MIS:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ *r = vreg_reg32_extract(vpl011->uartris & vpl011->uartimsc,
+ info);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ case IMSC:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ *r = vreg_reg32_extract(vpl011->uartimsc, info);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ case ICR:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ /* Only write is valid. */
+ return 0;
+
+ default:
+ gprintk(XENLOG_ERR, "vpl011: unhandled read r%d offset %#08x\n",
+ dabt.reg, vpl011_reg);
+ return 0;
+ }
+
+ return 1;
+
+bad_width:
+ gprintk(XENLOG_ERR, "vpl011: bad read width %d r%d offset %#08x\n",
+ dabt.size, dabt.reg, vpl011_reg);
+ domain_crash_synchronous();
+ return 0;
+
+}
+
+static int vpl011_mmio_write(struct vcpu *v,
+ mmio_info_t *info,
+ register_t r,
+ void *priv)
+{
+ struct hsr_dabt dabt = info->dabt;
+ uint32_t vpl011_reg = (uint32_t)(info->gpa - GUEST_PL011_BASE);
+ struct vpl011 *vpl011 = &v->domain->arch.vpl011;
+ struct domain *d = v->domain;
+ unsigned long flags;
+
+ switch ( vpl011_reg )
+ {
+ case DR:
+ {
+ uint32_t data = 0;
+
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ vreg_reg32_update(&data, r, info);
+ data &= 0xFF;
+ vpl011_write_data(v->domain, data);
+ return 1;
+ }
+
+ case RSR: /* Nothing to clear. */
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ return 1;
+
+ case FR:
+ case RIS:
+ case MIS:
+ goto write_ignore;
+
+ case IMSC:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ vreg_reg32_update(&vpl011->uartimsc, r, info);
+ vpl011_update_interrupt_status(v->domain);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ case ICR:
+ if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
+
+ VPL011_LOCK(d, flags);
+ vreg_reg32_clearbits(&vpl011->uartris, r, info);
+ vpl011_update_interrupt_status(d);
+ VPL011_UNLOCK(d, flags);
+ return 1;
+
+ default:
+ gprintk(XENLOG_ERR, "vpl011: unhandled write r%d offset %#08x\n",
+ dabt.reg, vpl011_reg);
+ return 0;
+ }
+
+write_ignore:
+ return 1;
+
+bad_width:
+ gprintk(XENLOG_ERR, "vpl011: bad write width %d r%d offset %#08x\n",
+ dabt.size, dabt.reg, vpl011_reg);
+ domain_crash_synchronous();
+ return 0;
+
+}
+
+static const struct mmio_handler_ops vpl011_mmio_handler = {
+ .read = vpl011_mmio_read,
+ .write = vpl011_mmio_write,
+};
+
+static void vpl011_data_avail(struct domain *d)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct xencons_interface *intf = vpl011->ring_buf;
+ XENCONS_RING_IDX in_cons, in_prod, out_cons, out_prod;
+ XENCONS_RING_IDX in_ring_qsize, out_ring_qsize;
+
+ VPL011_LOCK(d, flags);
+
+ in_cons = intf->in_cons;
+ in_prod = intf->in_prod;
+ out_cons = intf->out_cons;
+ out_prod = intf->out_prod;
+
+ smp_rmb();
+
+ in_ring_qsize = xencons_queued(in_prod,
+ in_cons,
+ sizeof(intf->in));
+
+ out_ring_qsize = xencons_queued(out_prod,
+ out_cons,
+ sizeof(intf->out));
+
+ /* Update the uart rx state if the buffer is not empty. */
+ if ( in_ring_qsize != 0 )
+ {
+ vpl011->uartfr &= ~RXFE;
+ if ( in_ring_qsize == sizeof(intf->in) )
+ vpl011->uartfr |= RXFF;
+ vpl011->uartris |= RXI;
+ }
+
+ /* Update the uart tx state if the buffer is not full. */
+ if ( out_ring_qsize != sizeof(intf->out) )
+ {
+ vpl011->uartfr &= ~TXFF;
+ vpl011->uartris |= TXI;
+ if ( out_ring_qsize == 0 )
+ {
+ vpl011->uartfr &= ~BUSY;
+ vpl011->uartfr |= TXFE;
+ }
+ }
+
+ vpl011_update_interrupt_status(d);
+
+ VPL011_UNLOCK(d, flags);
+}
+
+static void vpl011_notification(struct vcpu *v, unsigned int port)
+{
+ vpl011_data_avail(v->domain);
+}
+
+int domain_vpl011_init(struct domain *d, struct vpl011_init_info *info)
+{
+ int rc;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+
+ if ( vpl011->ring_buf )
+ return -EINVAL;
+
+ /* Map the guest PFN to Xen address space. */
+ rc = prepare_ring_for_helper(d,
+ gfn_x(info->gfn),
+ &vpl011->ring_page,
+ &vpl011->ring_buf);
+ if ( rc < 0 )
+ goto out;
+
+ 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);
+
+ register_mmio_handler(d, &vpl011_mmio_handler,
+ GUEST_PL011_BASE, GUEST_PL011_SIZE, NULL);
+
+ return 0;
+
+out2:
+ vgic_free_virq(d, GUEST_VPL011_SPI);
+
+out1:
+ destroy_ring_for_helper(&vpl011->ring_buf, vpl011->ring_page);
+
+out:
+ return rc;
+}
+
+void domain_vpl011_deinit(struct domain *d)
+{
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+
+ if ( !vpl011->ring_buf )
+ return;
+
+ free_xen_event_channel(d, vpl011->evtchn);
+ destroy_ring_for_helper(&vpl011->ring_buf, vpl011->ring_page);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
projects / xen.git / commitdiff