diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/char/Makefile | 2 | ||||
| -rw-r--r-- | drivers/char/hvc_lguest.c | 177 | ||||
| -rw-r--r-- | drivers/char/virtio_console.c | 225 |
4 files changed, 230 insertions, 178 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 65491103e0f..bf18d757b87 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -613,6 +613,10 @@ config HVC_XEN help Xen virtual console device driver +config VIRTIO_CONSOLE + bool + select HVC_DRIVER + config HVCS tristate "IBM Hypervisor Virtual Console Server support" depends on PPC_PSERIES diff --git a/drivers/char/Makefile b/drivers/char/Makefile index c78ff26647e..07304d50e0c 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -42,7 +42,6 @@ obj-$(CONFIG_SYNCLINK_GT) += synclink_gt.o obj-$(CONFIG_N_HDLC) += n_hdlc.o obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o obj-$(CONFIG_SX) += sx.o generic_serial.o -obj-$(CONFIG_LGUEST_GUEST) += hvc_lguest.o obj-$(CONFIG_RIO) += rio/ generic_serial.o obj-$(CONFIG_HVC_CONSOLE) += hvc_vio.o hvsi.o obj-$(CONFIG_HVC_ISERIES) += hvc_iseries.o @@ -50,6 +49,7 @@ obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o obj-$(CONFIG_HVC_BEAT) += hvc_beat.o obj-$(CONFIG_HVC_DRIVER) += hvc_console.o obj-$(CONFIG_HVC_XEN) += hvc_xen.o +obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o obj-$(CONFIG_RAW_DRIVER) += raw.o obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o obj-$(CONFIG_MSPEC) += mspec.o diff --git a/drivers/char/hvc_lguest.c b/drivers/char/hvc_lguest.c deleted file mode 100644 index efccb215583..00000000000 --- a/drivers/char/hvc_lguest.c +++ /dev/null @@ -1,177 +0,0 @@ -/*D:300 - * The Guest console driver - * - * This is a trivial console driver: we use lguest's DMA mechanism to send - * bytes out, and register a DMA buffer to receive bytes in. It is assumed to - * be present and available from the very beginning of boot. - * - * Writing console drivers is one of the few remaining Dark Arts in Linux. - * Fortunately for us, the path of virtual consoles has been well-trodden by - * the PowerPC folks, who wrote "hvc_console.c" to generically support any - * virtual console. We use that infrastructure which only requires us to write - * the basic put_chars and get_chars functions and call the right register - * functions. - :*/ - -/*M:002 The console can be flooded: while the Guest is processing input the - * Host can send more. Buffering in the Host could alleviate this, but it is a - * difficult problem in general. :*/ -/* Copyright (C) 2006 Rusty Russell, IBM Corporation - * - * 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. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - */ -#include <linux/err.h> -#include <linux/init.h> -#include <linux/lguest_bus.h> -#include <asm/paravirt.h> -#include "hvc_console.h" - -/*D:340 This is our single console input buffer, with associated "struct - * lguest_dma" referring to it. Note the 0-terminated length array, and the - * use of physical address for the buffer itself. */ -static char inbuf[256]; -static struct lguest_dma cons_input = { .used_len = 0, - .addr[0] = __pa(inbuf), - .len[0] = sizeof(inbuf), - .len[1] = 0 }; - -/*D:310 The put_chars() callback is pretty straightforward. - * - * First we put the pointer and length in a "struct lguest_dma": we only have - * one pointer, so we set the second length to 0. Then we use SEND_DMA to send - * the data to (Host) buffers attached to the console key. Usually a device's - * key is a physical address within the device's memory, but because the - * console device doesn't have any associated physical memory, we use the - * LGUEST_CONSOLE_DMA_KEY constant (aka 0). */ -static int put_chars(u32 vtermno, const char *buf, int count) -{ - struct lguest_dma dma; - - /* FIXME: DMA buffers in a "struct lguest_dma" are not allowed - * to go over page boundaries. This never seems to happen, - * but if it did we'd need to fix this code. */ - dma.len[0] = count; - dma.len[1] = 0; - dma.addr[0] = __pa(buf); - - lguest_send_dma(LGUEST_CONSOLE_DMA_KEY, &dma); - /* We're expected to return the amount of data we wrote: all of it. */ - return count; -} - -/*D:350 get_chars() is the callback from the hvc_console infrastructure when - * an interrupt is received. - * - * Firstly we see if our buffer has been filled: if not, we return. The rest - * of the code deals with the fact that the hvc_console() infrastructure only - * asks us for 16 bytes at a time. We keep a "cons_offset" variable for - * partially-read buffers. */ -static int get_chars(u32 vtermno, char *buf, int count) -{ - static int cons_offset; - - /* Nothing left to see here... */ - if (!cons_input.used_len) - return 0; - - /* You want more than we have to give? Well, try wanting less! */ - if (cons_input.used_len - cons_offset < count) - count = cons_input.used_len - cons_offset; - - /* Copy across to their buffer and increment offset. */ - memcpy(buf, inbuf + cons_offset, count); - cons_offset += count; - - /* Finished? Zero offset, and reset cons_input so Host will use it - * again. */ - if (cons_offset == cons_input.used_len) { - cons_offset = 0; - cons_input.used_len = 0; - } - return count; -} -/*:*/ - -static struct hv_ops lguest_cons = { - .get_chars = get_chars, - .put_chars = put_chars, -}; - -/*D:320 Console drivers are initialized very early so boot messages can go - * out. At this stage, the console is output-only. Our driver checks we're a - * Guest, and if so hands hvc_instantiate() the console number (0), priority - * (0), and the struct hv_ops containing the put_chars() function. */ -static int __init cons_init(void) -{ - if (strcmp(pv_info.name, "lguest") != 0) - return 0; - - return hvc_instantiate(0, 0, &lguest_cons); -} -console_initcall(cons_init); - -/*D:370 To set up and manage our virtual console, we call hvc_alloc() and - * stash the result in the private pointer of the "struct lguest_device". - * Since we never remove the console device we never need this pointer again, - * but using ->private is considered good form, and you never know who's going - * to copy your driver. - * - * Once the console is set up, we bind our input buffer ready for input. */ -static int lguestcons_probe(struct lguest_device *lgdev) -{ - int err; - - /* The first argument of hvc_alloc() is the virtual console number, so - * we use zero. The second argument is the interrupt number. - * - * The third argument is a "struct hv_ops" containing the put_chars() - * and get_chars() pointers. The final argument is the output buffer - * size: we use 256 and expect the Host to have room for us to send - * that much. */ - lgdev->private = hvc_alloc(0, lgdev_irq(lgdev), &lguest_cons, 256); - if (IS_ERR(lgdev->private)) - return PTR_ERR(lgdev->private); - - /* We bind a single DMA buffer at key LGUEST_CONSOLE_DMA_KEY. - * "cons_input" is that statically-initialized global DMA buffer we saw - * above, and we also give the interrupt we want. */ - err = lguest_bind_dma(LGUEST_CONSOLE_DMA_KEY, &cons_input, 1, - lgdev_irq(lgdev)); - if (err) - printk("lguest console: failed to bind buffer.\n"); - return err; -} -/* Note the use of lgdev_irq() for the interrupt number. We tell hvc_alloc() - * to expect input when this interrupt is triggered, and then tell - * lguest_bind_dma() that is the interrupt to send us when input comes in. */ - -/*D:360 From now on the console driver follows standard Guest driver form: - * register_lguest_driver() registers the device type and probe function, and - * the probe function sets up the device. - * - * The standard "struct lguest_driver": */ -static struct lguest_driver lguestcons_drv = { - .name = "lguestcons", - .owner = THIS_MODULE, - .device_type = LGUEST_DEVICE_T_CONSOLE, - .probe = lguestcons_probe, -}; - -/* The standard init function */ -static int __init hvc_lguest_init(void) -{ - return register_lguest_driver(&lguestcons_drv); -} -module_init(hvc_lguest_init); diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c new file mode 100644 index 00000000000..100e8a201e3 --- /dev/null +++ b/drivers/char/virtio_console.c @@ -0,0 +1,225 @@ +/*D:300 + * The Guest console driver + * + * Writing console drivers is one of the few remaining Dark Arts in Linux. + * Fortunately for us, the path of virtual consoles has been well-trodden by + * the PowerPC folks, who wrote "hvc_console.c" to generically support any + * virtual console. We use that infrastructure which only requires us to write + * the basic put_chars and get_chars functions and call the right register + * functions. + :*/ + +/*M:002 The console can be flooded: while the Guest is processing input the + * Host can send more. Buffering in the Host could alleviate this, but it is a + * difficult problem in general. :*/ +/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include <linux/err.h> +#include <linux/init.h> +#include <linux/virtio.h> +#include <linux/virtio_console.h> +#include "hvc_console.h" + +/*D:340 These represent our input and output console queues, and the virtio + * operations for them. */ +static struct virtqueue *in_vq, *out_vq; +static struct virtio_device *vdev; + +/* This is our input buffer, and how much data is left in it. */ +static unsigned int in_len; +static char *in, *inbuf; + +/* The operations for our console. */ +static struct hv_ops virtio_cons; + +/*D:310 The put_chars() callback is pretty straightforward. + * + * We turn the characters into a scatter-gather list, add it to the output + * queue and then kick the Host. Then we sit here waiting for it to finish: + * inefficient in theory, but in practice implementations will do it + * immediately (lguest's Launcher does). */ +static int put_chars(u32 vtermno, const char *buf, int count) +{ + struct scatterlist sg[1]; + unsigned int len; + + /* This is a convenient routine to initialize a single-elem sg list */ + sg_init_one(sg, buf, count); + + /* add_buf wants a token to identify this buffer: we hand it any + * non-NULL pointer, since there's only ever one buffer. */ + if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) == 0) { + /* Tell Host to go! */ + out_vq->vq_ops->kick(out_vq); + /* Chill out until it's done with the buffer. */ + while (!out_vq->vq_ops->get_buf(out_vq, &len)) + cpu_relax(); + } + + /* We're expected to return the amount of data we wrote: all of it. */ + return count; +} + +/* Create a scatter-gather list representing our input buffer and put it in the + * queue. */ +static void add_inbuf(void) +{ + struct scatterlist sg[1]; + sg_init_one(sg, inbuf, PAGE_SIZE); + + /* We should always be able to add one buffer to an empty queue. */ + if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) != 0) + BUG(); + in_vq->vq_ops->kick(in_vq); +} + +/*D:350 get_chars() is the callback from the hvc_console infrastructure when + * an interrupt is received. + * + * Most of the code deals with the fact that the hvc_console() infrastructure + * only asks us for 16 bytes at a time. We keep in_offset and in_used fields + * for partially-filled buffers. */ +static int get_chars(u32 vtermno, char *buf, int count) +{ + /* If we don't have an input queue yet, we can't get input. */ + BUG_ON(!in_vq); + + /* No buffer? Try to get one. */ + if (!in_len) { + in = in_vq->vq_ops->get_buf(in_vq, &in_len); + if (!in) + return 0; + } + + /* You want more than we have to give? Well, try wanting less! */ + if (in_len < count) + count = in_len; + + /* Copy across to their buffer and increment offset. */ + memcpy(buf, in, count); + in += count; + in_len -= count; + + /* Finished? Re-register buffer so Host will use it again. */ + if (in_len == 0) + add_inbuf(); + + return count; +} +/*:*/ + +/*D:320 Console drivers are initialized very early so boot messages can go out, + * so we do things slightly differently from the generic virtio initialization + * of the net and block drivers. + * + * At this stage, the console is output-only. It's too early to set up a + * virtqueue, so we let the drivers do some boutique early-output thing. */ +int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)) +{ + virtio_cons.put_chars = put_chars; + return hvc_instantiate(0, 0, &virtio_cons); +} + +/*D:370 Once we're further in boot, we get probed like any other virtio device. + * At this stage we set up the output virtqueue. + * + * To set up and manage our virtual console, we call hvc_alloc(). Since we + * never remove the console device we never need this pointer again. + * + * Finally we put our input buffer in the input queue, ready to receive. */ +static int virtcons_probe(struct virtio_device *dev) +{ + int err; + struct hvc_struct *hvc; + + vdev = dev; + + /* This is the scratch page we use to receive console input */ + inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!inbuf) { + err = -ENOMEM; + goto fail; + } + + /* Find the input queue. */ + /* FIXME: This is why we want to wean off hvc: we do nothing + * when input comes in. */ + in_vq = vdev->config->find_vq(vdev, NULL); + if (IS_ERR(in_vq)) { + err = PTR_ERR(in_vq); + goto free; + } + + out_vq = vdev->config->find_vq(vdev, NULL); + if (IS_ERR(out_vq)) { + err = PTR_ERR(out_vq); + goto free_in_vq; + } + + /* Start using the new console output. */ + virtio_cons.get_chars = get_chars; + virtio_cons.put_chars = put_chars; + + /* The first argument of hvc_alloc() is the virtual console number, so + * we use zero. The second argument is the interrupt number; we + * currently leave this as zero: it would be better not to use the + * hvc mechanism and fix this (FIXME!). + * + * The third argument is a "struct hv_ops" containing the put_chars() + * and get_chars() pointers. The final argument is the output buffer + * size: we can do any size, so we put PAGE_SIZE here. */ + hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE); + if (IS_ERR(hvc)) { + err = PTR_ERR(hvc); + goto free_out_vq; + } + + /* Register the input buffer the first time. */ + add_inbuf(); + return 0; + +free_out_vq: + vdev->config->del_vq(out_vq); +free_in_vq: + vdev->config->del_vq(in_vq); +free: + kfree(inbuf); +fail: + return err; +} + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_console = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = id_table, + .probe = virtcons_probe, +}; + +static int __init init(void) +{ + return register_virtio_driver(&virtio_console); +} +module_init(init); + +MODULE_DEVICE_TABLE(virtio, id_table); +MODULE_DESCRIPTION("Virtio console driver"); +MODULE_LICENSE("GPL"); |