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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 4/7] xen/arm: Implement a virtual UART
This code is based on the previous vuart0 implementation. Unlike the latter,
it's intend to replace UART stolen by XEN to DOM0 via dtuart=... on its
command line.
It's useful when the kernel is compiled with early printk enabled or for a
single platform. Most of the time, the hardcoded code to handle the UART
will need 2 registers: status and data, the others registers can be
implemented as RAZ/WI.
This commit will also drop support of early printk (based on vexpress pl011)
in the guest.
Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
Changes in v3:
- Fix typo
- Don't use "current" in vuart_print_char
- Remove unnecessary cast
- Update changeset
Changes in v2:
- Merge and update comments
- Use the renamed callback
---
xen/arch/arm/Makefile | 2 +-
xen/arch/arm/domain.c | 12 ++--
xen/arch/arm/io.c | 2 +-
xen/arch/arm/io.h | 2 +-
xen/arch/arm/vpl011.c | 152 ------------------------------------------
xen/arch/arm/vpl011.h | 35 ----------
xen/arch/arm/vuart.c | 150 +++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/vuart.h | 35 ++++++++++
xen/include/asm-arm/domain.h | 14 ++--
9 files changed, 204 insertions(+), 200 deletions(-)
delete mode 100644 xen/arch/arm/vpl011.c
delete mode 100644 xen/arch/arm/vpl011.h
create mode 100644 xen/arch/arm/vuart.c
create mode 100644 xen/arch/arm/vuart.h
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 5c13a65..003ac84 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -27,7 +27,7 @@ obj-y += shutdown.o
obj-y += traps.o
obj-y += vgic.o
obj-y += vtimer.o
-obj-y += vpl011.o
+obj-y += vuart.o
obj-y += hvm.o
obj-y += device.o
obj-y += decode.o
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 4e9cece..cb0424d 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -32,7 +32,7 @@
#include <asm/gic.h>
#include "vtimer.h"
-#include "vpl011.h"
+#include "vuart.h"
DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
@@ -525,8 +525,12 @@ int arch_domain_create(struct domain *d, unsigned int
domcr_flags)
if ( (rc = vcpu_domain_init(d)) != 0 )
goto fail;
- /* Domain 0 gets a real UART not an emulated one */
- if ( d->domain_id && (rc = domain_uart0_init(d)) != 0 )
+ /*
+ * Virtual UART is only used by linux early printk and decompress code.
+ * Only use it for dom0 because the linux kernel may not support
+ * multi-platform.
+ */
+ if ( (d->domain_id == 0) && (rc = domain_vuart_init(d)) )
goto fail;
return 0;
@@ -542,7 +546,7 @@ void arch_domain_destroy(struct domain *d)
{
p2m_teardown(d);
domain_vgic_free(d);
- domain_uart0_free(d);
+ domain_vuart_free(d);
free_xenheap_page(d->shared_info);
}
diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c
index ad28c26..a6db00b 100644
--- a/xen/arch/arm/io.c
+++ b/xen/arch/arm/io.c
@@ -25,7 +25,7 @@
static const struct mmio_handler *const mmio_handlers[] =
{
&vgic_distr_mmio_handler,
- &uart0_mmio_handler,
+ &vuart_mmio_handler,
};
#define MMIO_HANDLER_NR ARRAY_SIZE(mmio_handlers)
diff --git a/xen/arch/arm/io.h b/xen/arch/arm/io.h
index 661dce1..8d252c0 100644
--- a/xen/arch/arm/io.h
+++ b/xen/arch/arm/io.h
@@ -41,7 +41,7 @@ struct mmio_handler {
};
extern const struct mmio_handler vgic_distr_mmio_handler;
-extern const struct mmio_handler uart0_mmio_handler;
+extern const struct mmio_handler vuart_mmio_handler;
extern int handle_mmio(mmio_info_t *info);
diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
deleted file mode 100644
index 13ba623..0000000
--- a/xen/arch/arm/vpl011.c
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
- * xen/arch/arm/vpl011.c
- *
- * ARM PL011 UART Emulator (DEBUG)
- *
- * Ian Campbell <ian.campbell@xxxxxxxxxx>
- * Copyright (c) 2012 Citrix Systems.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that 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.
- */
-
-/*
- * This is not intended to be a full emulation of a PL011
- * device. Rather it is intended to provide a sufficient veneer of one
- * that early code (such as Linux's boot time decompressor) which
- * hardcodes output directly to such a device are able to make progress.
- *
- * This device is not intended to be enumerable or exposed to the OS
- * (e.g. via Device Tree).
- */
-
-#include <xen/config.h>
-#include <xen/lib.h>
-#include <xen/sched.h>
-#include <xen/errno.h>
-#include <xen/ctype.h>
-
-#include "io.h"
-
-#define UART0_START 0x1c090000
-#define UART0_END (UART0_START+65536)
-
-#define UARTDR 0x000
-#define UARTFR 0x018
-
-int domain_uart0_init(struct domain *d)
-{
- ASSERT( d->domain_id );
-
- spin_lock_init(&d->arch.uart0.lock);
- d->arch.uart0.idx = 0;
-
- d->arch.uart0.buf = xzalloc_array(char, VPL011_BUF_SIZE);
- if ( !d->arch.uart0.buf )
- return -ENOMEM;
-
- return 0;
-
-}
-
-void domain_uart0_free(struct domain *d)
-{
- xfree(d->arch.uart0.buf);
-}
-
-static void uart0_print_char(char c)
-{
- struct vpl011 *uart = ¤t->domain->arch.uart0;
-
- /* Accept only printable characters, newline, and horizontal tab. */
- if ( !isprint(c) && (c != '\n') && (c != '\t') )
- return ;
-
- spin_lock(&uart->lock);
- uart->buf[uart->idx++] = c;
- if ( (uart->idx == (VPL011_BUF_SIZE - 2)) || (c == '\n') )
- {
- if ( c != '\n' )
- uart->buf[uart->idx++] = '\n';
- uart->buf[uart->idx] = '\0';
- printk(XENLOG_G_DEBUG "DOM%u: %s",
- current->domain->domain_id, uart->buf);
- uart->idx = 0;
- }
- spin_unlock(&uart->lock);
-}
-
-static int uart0_mmio_check(struct vcpu *v, paddr_t addr)
-{
- struct domain *d = v->domain;
-
- return d->domain_id != 0 && addr >= UART0_START && addr < UART0_END;
-}
-
-static int uart0_mmio_read(struct vcpu *v, mmio_info_t *info)
-{
- struct hsr_dabt dabt = info->dabt;
- struct cpu_user_regs *regs = guest_cpu_user_regs();
- register_t *r = select_user_reg(regs, dabt.reg);
- int offset = (int)(info->gpa - UART0_START);
-
- switch ( offset )
- {
- case UARTDR:
- *r = 0;
- return 1;
- case UARTFR:
- *r = 0x87; /* All holding registers empty, ready to send etc */
- return 1;
- default:
- printk("VPL011: unhandled read r%d offset %#08x\n",
- dabt.reg, offset);
- domain_crash_synchronous();
- }
-}
-
-static int uart0_mmio_write(struct vcpu *v, mmio_info_t *info)
-{
- struct hsr_dabt dabt = info->dabt;
- struct cpu_user_regs *regs = guest_cpu_user_regs();
- register_t *r = select_user_reg(regs, dabt.reg);
- int offset = (int)(info->gpa - UART0_START);
-
- switch ( offset )
- {
- case UARTDR:
- /* ignore any status bits */
- uart0_print_char((int)((*r) & 0xFF));
- return 1;
- case UARTFR:
- /* Silently ignore */
- return 1;
- default:
- printk("VPL011: unhandled write r%d=%"PRIregister" offset %#08x\n",
- dabt.reg, *r, offset);
- domain_crash_synchronous();
- }
-}
-
-const struct mmio_handler uart0_mmio_handler = {
- .check_handler = uart0_mmio_check,
- .read_handler = uart0_mmio_read,
- .write_handler = uart0_mmio_write,
-};
-
-/*
- * Local variables:
- * mode: C
- * c-file-style: "BSD"
- * c-basic-offset: 4
- * indent-tabs-mode: nil
- * End:
- */
-
diff --git a/xen/arch/arm/vpl011.h b/xen/arch/arm/vpl011.h
deleted file mode 100644
index f0d0a82..0000000
--- a/xen/arch/arm/vpl011.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * xen/arch/arm/vpl011.h
- *
- * ARM PL011 Emulation Support
- *
- * Ian Campbell <ian.campbell@xxxxxxxxxx>
- * Copyright (c) 2012 Citrix Systems.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that 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.
- */
-
-#ifndef __ARCH_ARM_VPL011_H__
-#define __ARCH_ARM_VPL011_H__
-
-extern int domain_uart0_init(struct domain *d);
-extern void domain_uart0_free(struct domain *d);
-
-#endif
-
-/*
- * Local variables:
- * mode: C
- * c-file-style: "BSD"
- * c-basic-offset: 4
- * indent-tabs-mode: nil
- * End:
- */
diff --git a/xen/arch/arm/vuart.c b/xen/arch/arm/vuart.c
new file mode 100644
index 0000000..b9d3ced
--- /dev/null
+++ b/xen/arch/arm/vuart.c
@@ -0,0 +1,150 @@
+/*
+ * xen/arch/arm/vuart.c
+ *
+ * Virtual UART Emulator.
+ *
+ * This emulator uses the information from dtuart. This is not intended to be
+ * a full emulation of an UART device. Rather it is intended to provide a
+ * sufficient veneer of one that early code (such as Linux's boot time
+ * decompressor) which hardcodes output directly to such a device are able to
+ * make progress.
+ *
+ * The minimal register set to emulate an UART are:
+ * - Single byte transmit register
+ * - Single status register
+ *
+ * /!\ This device is not intended to be enumerable or exposed to the OS
+ * (e.g. via Device Tree).
+ *
+ * Julien Grall <julien.grall@xxxxxxxxxx>
+ * Ian Campbell <ian.campbell@xxxxxxxxxx>
+ * Copyright (c) 2012 Citrix Systems.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+
+#include <xen/config.h>
+#include <xen/lib.h>
+#include <xen/sched.h>
+#include <xen/errno.h>
+#include <xen/ctype.h>
+#include <xen/serial.h>
+
+#include "vuart.h"
+#include "io.h"
+
+#define domain_has_vuart(d) ((d)->arch.vuart.info != NULL)
+
+int domain_vuart_init(struct domain *d)
+{
+ ASSERT( !d->domain_id );
+
+ d->arch.vuart.info = serial_vuart_info(SERHND_DTUART);
+ if ( !d->arch.vuart.info )
+ return 0;
+
+ spin_lock_init(&d->arch.vuart.lock);
+ d->arch.vuart.idx = 0;
+
+ d->arch.vuart.buf = xzalloc_array(char, VUART_BUF_SIZE);
+ if ( !d->arch.vuart.buf )
+ return -ENOMEM;
+
+ return 0;
+}
+
+void domain_vuart_free(struct domain *d)
+{
+ if ( !domain_has_vuart(d) )
+ return;
+
+ xfree(d->arch.vuart.buf);
+}
+
+static void vuart_print_char(struct vcpu *v, char c)
+{
+ struct domain *d = v->domain;
+ struct vuart *uart = &d->arch.vuart;
+
+ /* Accept only printable characters, newline, and horizontal tab. */
+ if ( !isprint(c) && (c != '\n') && (c != '\t') )
+ return ;
+
+ spin_lock(&uart->lock);
+ uart->buf[uart->idx++] = c;
+ if ( (uart->idx == (VUART_BUF_SIZE - 2)) || (c == '\n') )
+ {
+ if ( c != '\n' )
+ uart->buf[uart->idx++] = '\n';
+ uart->buf[uart->idx] = '\0';
+ printk(XENLOG_G_DEBUG "DOM%u: %s", d->domain_id, uart->buf);
+ uart->idx = 0;
+ }
+ spin_unlock(&uart->lock);
+}
+
+static int vuart_mmio_check(struct vcpu *v, paddr_t addr)
+{
+ const struct vuart_info *info = v->domain->arch.vuart.info;
+
+ return (domain_has_vuart(v->domain) && addr >= info->base_addr &&
+ addr <= (info->base_addr + info->size));
+}
+
+static int vuart_mmio_read(struct vcpu *v, mmio_info_t *info)
+{
+ struct domain *d = v->domain;
+ struct hsr_dabt dabt = info->dabt;
+ struct cpu_user_regs *regs = guest_cpu_user_regs();
+ register_t *r = select_user_reg(regs, dabt.reg);
+ paddr_t offset = info->gpa - d->arch.vuart.info->base_addr;
+
+ /* By default zeroed the register */
+ *r = 0;
+
+ if ( offset == d->arch.vuart.info->status_off )
+ /* All holding registers empty, ready to send etc */
+ *r = d->arch.vuart.info->status;
+
+ return 1;
+}
+
+static int vuart_mmio_write(struct vcpu *v, mmio_info_t *info)
+{
+ struct domain *d = v->domain;
+ struct hsr_dabt dabt = info->dabt;
+ struct cpu_user_regs *regs = guest_cpu_user_regs();
+ register_t *r = select_user_reg(regs, dabt.reg);
+ paddr_t offset = info->gpa - d->arch.vuart.info->base_addr;
+
+ if ( offset == d->arch.vuart.info->data_off )
+ /* ignore any status bits */
+ vuart_print_char(v, *r & 0xFF);
+
+ return 1;
+}
+
+const struct mmio_handler vuart_mmio_handler = {
+ .check_handler = vuart_mmio_check,
+ .read_handler = vuart_mmio_read,
+ .write_handler = vuart_mmio_write,
+};
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
+
diff --git a/xen/arch/arm/vuart.h b/xen/arch/arm/vuart.h
new file mode 100644
index 0000000..9445e50
--- /dev/null
+++ b/xen/arch/arm/vuart.h
@@ -0,0 +1,35 @@
+/*
+ * xen/arch/arm/vuart.h
+ *
+ * Virtual UART Emulation Support
+ *
+ * Ian Campbell <ian.campbell@xxxxxxxxxx>
+ * Copyright (c) 2012 Citrix Systems.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#ifndef __ARCH_ARM_VUART_H__
+#define __ARCH_ARM_VUART_H__
+
+int domain_vuart_init(struct domain *d);
+void domain_vuart_free(struct domain *d);
+
+#endif /* __ARCH_ARM_VUART_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 89f88f6..67bfbbc 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -8,6 +8,7 @@
#include <asm/p2m.h>
#include <asm/vfp.h>
#include <public/hvm/params.h>
+#include <xen/serial.h>
/* Represents state corresponding to a block of 32 interrupts */
struct vgic_irq_rank {
@@ -103,12 +104,13 @@ struct arch_domain
paddr_t cbase; /* CPU base address */
} vgic;
- struct vpl011 {
-#define VPL011_BUF_SIZE 128
- char *buf;
- int idx;
- spinlock_t lock;
- } uart0;
+ struct vuart {
+#define VUART_BUF_SIZE 128
+ char *buf;
+ int idx;
+ const struct vuart_info *info;
+ spinlock_t lock;
+ } vuart;
} __cacheline_aligned;
--
1.7.10.4
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