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/*
* Remote Processor Framework
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
*
* Ohad Ben-Cohen <ohad@wizery.com>
* Brian Swetland <swetland@google.com>
* Mark Grosen <mgrosen@ti.com>
* Fernando Guzman Lugo <fernando.lugo@ti.com>
* Suman Anna <s-anna@ti.com>
* Robert Tivy <rtivy@ti.com>
* Armando Uribe De Leon <x0095078@ti.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* 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.
*/

#define pr_fmt(fmt) "%s: " fmt, __func__

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/dma-mapping.h>
#include <linux/firmware.h>
#include <linux/string.h>
#include <linux/debugfs.h>
#include <linux/remoteproc.h>
#include <linux/iommu.h>
#include <linux/idr.h>
#include <linux/elf.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_ring.h>
#include <asm/byteorder.h>

#include "remoteproc_internal.h"

typedef int (*rproc_handle_resources_t)(struct rproc *rproc,
struct resource_table *table, int len);
typedef int (*rproc_handle_resource_t)(struct rproc *rproc, void *, int avail);

/* Unique indices for remoteproc devices */
static DEFINE_IDA(rproc_dev_index);

/*
* This is the IOMMU fault handler we register with the IOMMU API
* (when relevant; not all remote processors access memory through
* an IOMMU).
*
* IOMMU core will invoke this handler whenever the remote processor
* will try to access an unmapped device address.
*
* Currently this is mostly a stub, but it will be later used to trigger
* the recovery of the remote processor.
*/
static int rproc_iommu_fault(struct iommu_domain *domain, struct device *dev,
unsigned long iova, int flags, void *token)
{
dev_err(dev, "iommu fault: da 0x%lx flags 0x%x\n", iova, flags);

/*
* Let the iommu core know we're not really handling this fault;
* we just plan to use this as a recovery trigger.
*/
return -ENOSYS;
}

static int rproc_enable_iommu(struct rproc *rproc)
{
struct iommu_domain *domain;
struct device *dev = rproc->dev.parent;
int ret;

/*
* We currently use iommu_present() to decide if an IOMMU
* setup is needed.
*
* This works for simple cases, but will easily fail with
* platforms that do have an IOMMU, but not for this specific
* rproc.
*
* This will be easily solved by introducing hw capabilities
* that will be set by the remoteproc driver.
*/
if (!iommu_present(dev->bus)) {
dev_dbg(dev, "iommu not found\n");
return 0;
}

domain = iommu_domain_alloc(dev->bus);
if (!domain) {
dev_err(dev, "can't alloc iommu domain\n");
return -ENOMEM;
}

iommu_set_fault_handler(domain, rproc_iommu_fault, rproc);

ret = iommu_attach_device(domain, dev);
if (ret) {
dev_err(dev, "can't attach iommu device: %d\n", ret);
goto free_domain;
}

rproc->domain = domain;

return 0;

free_domain:
iommu_domain_free(domain);
return ret;
}

static void rproc_disable_iommu(struct rproc *rproc)
{
struct iommu_domain *domain = rproc->domain;
struct device *dev = rproc->dev.parent;

if (!domain)
return;

iommu_detach_device(domain, dev);
iommu_domain_free(domain);

return;
}

/*
* Some remote processors will ask us to allocate them physically contiguous
* memory regions (which we call "carveouts"), and map them to specific
* device addresses (which are hardcoded in the firmware).
*
* They may then ask us to copy objects into specific device addresses (e.g.
* code/data sections) or expose us certain symbols in other device address
* (e.g. their trace buffer).
*
* This function is an internal helper with which we can go over the allocated
* carveouts and translate specific device address to kernel virtual addresses
* so we can access the referenced memory.
*
* Note: phys_to_virt(iommu_iova_to_phys(rproc->domain, da)) will work too,
* but only on kernel direct mapped RAM memory. Instead, we're just using
* here the output of the DMA API, which should be more correct.
*/
void *rproc_da_to_va(struct rproc *rproc, u64 da, int len)
{
struct rproc_mem_entry *carveout;
void *ptr = NULL;

list_for_each_entry(carveout, &rproc->carveouts, node) {
int offset = da - carveout->da;

/* try next carveout if da is too small */
if (offset < 0)
continue;

/* try next carveout if da is too large */
if (offset + len > carveout->len)
continue;

ptr = carveout->va + offset;

break;
}

return ptr;
}
EXPORT_SYMBOL(rproc_da_to_va);

int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
{
struct rproc *rproc = rvdev->rproc;
struct device *dev = &rproc->dev;
struct rproc_vring *rvring = &rvdev->vring[i];
dma_addr_t dma;
void *va;
int ret, size, notifyid;

/* actual size of vring (in bytes) */
size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));

if (!idr_pre_get(&rproc->notifyids, GFP_KERNEL)) {
dev_err(dev, "idr_pre_get failed\n");
return -ENOMEM;
}

/*
* Allocate non-cacheable memory for the vring. In the future
* this call will also configure the IOMMU for us
* TODO: let the rproc know the da of this vring
*/
va = dma_alloc_coherent(dev->parent, size, &dma, GFP_KERNEL);
if (!va) {
dev_err(dev->parent, "dma_alloc_coherent failed\n");
return -EINVAL;
}

/*
* Assign an rproc-wide unique index for this vring
* TODO: assign a notifyid for rvdev updates as well
* TODO: let the rproc know the notifyid of this vring
* TODO: support predefined notifyids (via resource table)
*/
ret = idr_get_new(&rproc->notifyids, rvring, &notifyid);
if (ret) {
dev_err(dev, "idr_get_new failed: %d\n", ret);
dma_free_coherent(dev->parent, size, va, dma);
return ret;
}

dev_dbg(dev, "vring%d: va %p dma %x size %x idr %d\n", i, va,
dma, size, notifyid);

rvring->va = va;
rvring->dma = dma;
rvring->notifyid = notifyid;

return 0;
}

static int
rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
{
struct rproc *rproc = rvdev->rproc;
struct device *dev = &rproc->dev;
struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
struct rproc_vring *rvring = &rvdev->vring[i];

dev_dbg(dev, "vdev rsc: vring%d: da %x, qsz %d, align %d\n",
i, vring->da, vring->num, vring->align);

/* make sure reserved bytes are zeroes */
if (vring->reserved) {
dev_err(dev, "vring rsc has non zero reserved bytes\n");
return -EINVAL;
}

/* verify queue size and vring alignment are sane */
if (!vring->num || !vring->align) {
dev_err(dev, "invalid qsz (%d) or alignment (%d)\n",
vring->num, vring->align);
return -EINVAL;
}

rvring->len = vring->num;
rvring->align = vring->align;
rvring->rvdev = rvdev;

return 0;
}

void rproc_free_vring(struct rproc_vring *rvring)
{
int size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
struct rproc *rproc = rvring->rvdev->rproc;

dma_free_coherent(rproc->dev.parent, size, rvring->va, rvring->dma);
idr_remove(&rproc->notifyids, rvring->notifyid);
}

/**
* rproc_handle_vdev() - handle a vdev fw resource
* @rproc: the remote processor
* @rsc: the vring resource descriptor
* @avail: size of available data (for sanity checking the image)
*
* This resource entry requests the host to statically register a virtio
* device (vdev), and setup everything needed to support it. It contains
* everything needed to make it possible: the virtio device id, virtio
* device features, vrings information, virtio config space, etc...
*
* Before registering the vdev, the vrings are allocated from non-cacheable
* physically contiguous memory. Currently we only support two vrings per
* remote processor (temporary limitation). We might also want to consider
* doing the vring allocation only later when ->find_vqs() is invoked, and
* then release them upon ->del_vqs().
*
* Note: @da is currently not really handled correctly: we dynamically
* allocate it using the DMA API, ignoring requested hard coded addresses,
* and we don't take care of any required IOMMU programming. This is all
* going to be taken care of when the generic iommu-based DMA API will be
* merged. Meanwhile, statically-addressed iommu-based firmware images should
* use RSC_DEVMEM resource entries to map their required @da to the physical
* address of their base CMA region (ouch, hacky!).
*
* Returns 0 on success, or an appropriate error code otherwise
*/
static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
int avail)
{
struct device *dev = &rproc->dev;
struct rproc_vdev *rvdev;
int i, ret;

/* make sure resource isn't truncated */
if (sizeof(*rsc) + rsc->num_of_vrings * sizeof(struct fw_rsc_vdev_vring)
+ rsc->config_len > avail) {
dev_err(dev, "vdev rsc is truncated\n");
return -EINVAL;
}

/* make sure reserved bytes are zeroes */
if (rsc->reserved[0] || rsc->reserved[1]) {
dev_err(dev, "vdev rsc has non zero reserved bytes\n");
return -EINVAL;
}

dev_dbg(dev, "vdev rsc: id %d, dfeatures %x, cfg len %d, %d vrings\n",
rsc->id, rsc->dfeatures, rsc->config_len, rsc->num_of_vrings);

/* we currently support only two vrings per rvdev */
if (rsc->num_of_vrings > ARRAY_SIZE(rvdev->vring)) {
dev_err(dev, "too many vrings: %d\n", rsc->num_of_vrings);
return -EINVAL;
}

rvdev = kzalloc(sizeof(struct rproc_vdev), GFP_KERNEL);
if (!rvdev)
return -ENOMEM;

rvdev->rproc = rproc;

/* parse the vrings */
for (i = 0; i < rsc->num_of_vrings; i++) {
ret = rproc_parse_vring(rvdev, rsc, i);
if (ret)
goto free_rvdev;
}

/* remember the device features */
rvdev->dfeatures = rsc->dfeatures;

list_add_tail(&rvdev->node, &rproc->rvdevs);

/* it is now safe to add the virtio device */
ret = rproc_add_virtio_dev(rvdev, rsc->id);
if (ret)
goto free_rvdev;

return 0;

free_rvdev:
kfree(rvdev);
return ret;
}

/**
* rproc_handle_trace() - handle a shared trace buffer resource
* @rproc: the remote processor
* @rsc: the trace resource descriptor
* @avail: size of available data (for sanity checking the image)
*
* In case the remote processor dumps trace logs into memory,
* export it via debugfs.
*
* Currently, the 'da' member of @rsc should contain the device address
* where the remote processor is dumping the traces. Later we could also
* support dynamically allocating this address using the generic
* DMA API (but currently there isn't a use case for that).
*
* Returns 0 on success, or an appropriate error code otherwise
*/
static int rproc_handle_trace(struct rproc *rproc, struct fw_rsc_trace *rsc,
int avail)
{
struct rproc_mem_entry *trace;
struct device *dev = &rproc->dev;
void *ptr;
char name[15];

if (sizeof(*rsc) > avail) {
dev_err(dev, "trace rsc is truncated\n");
return -EINVAL;
}

/* make sure reserved bytes are zeroes */
if (rsc->reserved) {
dev_err(dev, "trace rsc has non zero reserved bytes\n");
return -EINVAL;
}

/* what's the kernel address of this resource ? */
ptr = rproc_da_to_va(rproc, rsc->da, rsc->len);
if (!ptr) {
dev_err(dev, "erroneous trace resource entry\n");
return -EINVAL;
}

trace = kzalloc(sizeof(*trace), GFP_KERNEL);
if (!trace) {
dev_err(dev, "kzalloc trace failed\n");
return -ENOMEM;
}

/* set the trace buffer dma properties */
trace->len = rsc->len;
trace->va = ptr;

/* make sure snprintf always null terminates, even if truncating */
snprintf(name, sizeof(name), "trace%d", rproc->num_traces);

/* create the debugfs entry */
trace->priv = rproc_create_trace_file(name, rproc, trace);
if (!trace->priv) {
trace->va = NULL;
kfree(trace);
return -EINVAL;
}

list_add_tail(&trace->node, &rproc->traces);

rproc->num_traces++;

dev_dbg(dev, "%s added: va %p, da 0x%x, len 0x%x\n", name, ptr,
rsc->da, rsc->len);

return 0;
}

/**
* rproc_handle_devmem() - handle devmem resource entry
* @rproc: remote processor handle
* @rsc: the devmem resource entry
* @avail: size of available data (for sanity checking the image)
*
* Remote processors commonly need to access certain on-chip peripherals.
*
* Some of these remote processors access memory via an iommu device,
* and might require us to configure their iommu before they can access
* the on-chip peripherals they need.
*
* This resource entry is a request to map such a peripheral device.
*
* These devmem entries will contain the physical address of the device in
* the 'pa' member. If a specific device address is expected, then 'da' will
* contain it (currently this is the only use case supported). 'len' will
* contain the size of the physical region we need to map.
*
* Currently we just "trust" those devmem entries to contain valid physical
* addresses, but this is going to change: we want the implementations to
* tell us ranges of physical addresses the firmware is allowed to request,
* and not allow firmwares to request access to physical addresses that
* are outside those ranges.
*/
static int rproc_handle_devmem(struct rproc *rproc, struct fw_rsc_devmem *rsc,
int avail)
{
struct rproc_mem_entry *mapping;
struct device *dev = &rproc->dev;
int ret;

/* no point in handling this resource without a valid iommu domain */
if (!rproc->domain)
return -EINVAL;

if (sizeof(*rsc) > avail) {
dev_err(dev, "devmem rsc is truncated\n");
return -EINVAL;
}

/* make sure reserved bytes are zeroes */
if (rsc->reserved) {
dev_err(dev, "devmem rsc has non zero reserved bytes\n");
return -EINVAL;
}

mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
if (!mapping) {
dev_err(dev, "kzalloc mapping failed\n");
return -ENOMEM;
}

ret = iommu_map(rproc->domain, rsc->da, rsc->pa, rsc->len, rsc->flags);
if (ret) {
dev_err(dev, "failed to map devmem: %d\n", ret);
goto out;
}

/*
* We'll need this info later when we'll want to unmap everything
* (e.g. on shutdown).
*
* We can't trust the remote processor not to change the resource
* table, so we must maintain this info independently.
*/
mapping->da = rsc->da;
mapping->len = rsc->len;
list_add_tail(&mapping->node, &rproc->mappings);

dev_dbg(dev, "mapped devmem pa 0x%x, da 0x%x, len 0x%x\n",
rsc->pa, rsc->da, rsc->len);

return 0;

out:
kfree(mapping);
return ret;
}

/**
* rproc_handle_carveout() - handle phys contig memory allocation requests
* @rproc: rproc handle
* @rsc: the resource entry
* @avail: size of available data (for image validation)
*
* This function will handle firmware requests for allocation of physically
* contiguous memory regions.
*
* These request entries should come first in the firmware's resource table,
* as other firmware entries might request placing other data objects inside
* these memory regions (e.g. data/code segments, trace resource entries, ...).
*
* Allocating memory this way helps utilizing the reserved physical memory
* (e.g. CMA) more efficiently, and also minimizes the number of TLB entries
* needed to map it (in case @rproc is using an IOMMU). Reducing the TLB
* pressure is important; it may have a substantial impact on performance.
*/
static int rproc_handle_carveout(struct rproc *rproc,
struct fw_rsc_carveout *rsc, int avail)
{
struct rproc_mem_entry *carveout, *mapping;
struct device *dev = &rproc->dev;
dma_addr_t dma;
void *va;
int ret;

if (sizeof(*rsc) > avail) {
dev_err(dev, "carveout rsc is truncated\n");
return -EINVAL;
}

/* make sure reserved bytes are zeroes */
if (rsc->reserved) {
dev_err(dev, "carveout rsc has non zero reserved bytes\n");
return -EINVAL;
}

dev_dbg(dev, "carveout rsc: da %x, pa %x, len %x, flags %x\n",
rsc->da, rsc->pa, rsc->len, rsc->flags);

mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
if (!mapping) {
dev_err(dev, "kzalloc mapping failed\n");
return -ENOMEM;
}

carveout = kzalloc(sizeof(*carveout), GFP_KERNEL);
if (!carveout) {
dev_err(dev, "kzalloc carveout failed\n");
ret = -ENOMEM;
goto free_mapping;
}

va = dma_alloc_coherent(dev->parent, rsc->len, &dma, GFP_KERNEL);
if (!va) {
dev_err(dev->parent, "dma_alloc_coherent err: %d\n", rsc->len);
ret = -ENOMEM;
goto free_carv;
}

dev_dbg(dev, "carveout va %p, dma %x, len 0x%x\n", va, dma, rsc->len);

/*
* Ok, this is non-standard.
*
* Sometimes we can't rely on the generic iommu-based DMA API
* to dynamically allocate the device address and then set the IOMMU
* tables accordingly, because some remote processors might
* _require_ us to use hard coded device addresses that their
* firmware was compiled with.
*
* In this case, we must use the IOMMU API directly and map
* the memory to the device address as expected by the remote
* processor.
*
* Obviously such remote processor devices should not be configured
* to use the iommu-based DMA API: we expect 'dma' to contain the
* physical address in this case.
*/
if (rproc->domain) {
ret = iommu_map(rproc->domain, rsc->da, dma, rsc->len,
rsc->flags);
if (ret) {
dev_err(dev, "iommu_map failed: %d\n", ret);
goto dma_free;
}

/*
* We'll need this info later when we'll want to unmap
* everything (e.g. on shutdown).
*
* We can't trust the remote processor not to change the
* resource table, so we must maintain this info independently.
*/
mapping->da = rsc->da;
mapping->len = rsc->len;
list_add_tail(&mapping->node, &rproc->mappings);

dev_dbg(dev, "carveout mapped 0x%x to 0x%x\n", rsc->da, dma);
}

/*
* Some remote processors might need to know the pa
* even though they are behind an IOMMU. E.g., OMAP4's
* remote M3 processor needs this so it can control
* on-chip hardware accelerators that are not behind
* the IOMMU, and therefor must know the pa.
*
* Generally we don't want to expose physical addresses
* if we don't have to (remote processors are generally
* _not_ trusted), so we might want to do this only for
* remote processor that _must_ have this (e.g. OMAP4's
* dual M3 subsystem).
*
* Non-IOMMU processors might also want to have this info.
* In this case, the device address and the physical address
* are the same.
*/
rsc->pa = dma;

carveout->va = va;
carveout->len = rsc->len;
carveout->dma = dma;
carveout->da = rsc->da;

list_add_tail(&carveout->node, &rproc->carveouts);

return 0;

dma_free:
dma_free_coherent(dev->parent, rsc->len, va, dma);
free_carv:
kfree(carveout);
free_mapping:
kfree(mapping);
return ret;
}

/*
* A lookup table for resource handlers. The indices are defined in
* enum fw_resource_type.
*/
static rproc_handle_resource_t rproc_handle_rsc[] = {
[RSC_CARVEOUT] = (rproc_handle_resource_t)rproc_handle_carveout,
[RSC_DEVMEM] = (rproc_handle_resource_t)rproc_handle_devmem,
[RSC_TRACE] = (rproc_handle_resource_t)rproc_handle_trace,
[RSC_VDEV] = NULL, /* VDEVs were handled upon registrarion */
};

/* handle firmware resource entries before booting the remote processor */
static int
rproc_handle_boot_rsc(struct rproc *rproc, struct resource_table *table, int len)
{
struct device *dev = &rproc->dev;
rproc_handle_resource_t handler;
int ret = 0, i;

for (i = 0; i < table->num; i++) {
int offset = table->offset[i];
struct fw_rsc_hdr *hdr = (void *)table + offset;
int avail = len - offset - sizeof(*hdr);
void *rsc = (void *)hdr + sizeof(*hdr);

/* make sure table isn't truncated */
if (avail < 0) {
dev_err(dev, "rsc table is truncated\n");
return -EINVAL;
}

dev_dbg(dev, "rsc: type %d\n", hdr->type);

if (hdr->type >= RSC_LAST) {
dev_warn(dev, "unsupported resource %d\n", hdr->type);
continue;
}

handler = rproc_handle_rsc[hdr->type];
if (!handler)
continue;

ret = handler(rproc, rsc, avail);
if (ret)
break;
}

return ret;
}

/* handle firmware resource entries while registering the remote processor */
static int
rproc_handle_virtio_rsc(struct rproc *rproc, struct resource_table *table, int len)
{
struct device *dev = &rproc->dev;
int ret = 0, i;

for (i = 0; i < table->num; i++) {
int offset = table->offset[i];
struct fw_rsc_hdr *hdr = (void *)table + offset;
int avail = len - offset - sizeof(*hdr);
struct fw_rsc_vdev *vrsc;

/* make sure table isn't truncated */
if (avail < 0) {
dev_err(dev, "rsc table is truncated\n");
return -EINVAL;
}

dev_dbg(dev, "%s: rsc type %d\n", __func__, hdr->type);

if (hdr->type != RSC_VDEV)
continue;

vrsc = (struct fw_rsc_vdev *)hdr->data;

ret = rproc_handle_vdev(rproc, vrsc, avail);
if (ret)
break;
}

return ret;
}

/**
* rproc_resource_cleanup() - clean up and free all acquired resources
* @rproc: rproc handle
*
* This function will free all resources acquired for @rproc, and it
* is called whenever @rproc either shuts down or fails to boot.
*/
static void rproc_resource_cleanup(struct rproc *rproc)
{
struct rproc_mem_entry *entry, *tmp;
struct device *dev = &rproc->dev;

/* clean up debugfs trace entries */
list_for_each_entry_safe(entry, tmp, &rproc->traces, node) {
rproc_remove_trace_file(entry->priv);
rproc->num_traces--;
list_del(&entry->node);
kfree(entry);
}

/* clean up carveout allocations */
list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
dma_free_coherent(dev->parent, entry->len, entry->va, entry->dma);
list_del(&entry->node);
kfree(entry);
}

/* clean up iommu mapping entries */
list_for_each_entry_safe(entry, tmp, &rproc->mappings, node) {
size_t unmapped;

unmapped = iommu_unmap(rproc->domain, entry->da, entry->len);
if (unmapped != entry->len) {
/* nothing much to do besides complaining */
dev_err(dev, "failed to unmap %u/%zu\n", entry->len,
unmapped);
}

list_del(&entry->node);
kfree(entry);
}
}

/*
* take a firmware and boot a remote processor with it.
*/
static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
{
struct device *dev = &rproc->dev;
const char *name = rproc->firmware;
struct resource_table *table;
int ret, tablesz;

ret = rproc_fw_sanity_check(rproc, fw);
if (ret)
return ret;

dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);

/*
* if enabling an IOMMU isn't relevant for this rproc, this is
* just a nop
*/
ret = rproc_enable_iommu(rproc);
if (ret) {
dev_err(dev, "can't enable iommu: %d\n", ret);
return ret;
}

rproc->bootaddr = rproc_get_boot_addr(rproc, fw);

/* look for the resource table */
table = rproc_find_rsc_table(rproc, fw, &tablesz);
if (!table) {
ret = -EINVAL;
goto clean_up;
}

/* handle fw resources which are required to boot rproc */
ret = rproc_handle_boot_rsc(rproc, table, tablesz);
if (ret) {
dev_err(dev, "Failed to process resources: %d\n", ret);
goto clean_up;
}

/* load the ELF segments to memory */
ret = rproc_load_segments(rproc, fw);
if (ret) {
dev_err(dev, "Failed to load program segments: %d\n", ret);
goto clean_up;
}

/* power up the remote processor */
ret = rproc->ops->start(rproc);
if (ret) {
dev_err(dev, "can't start rproc %s: %d\n", rproc->name, ret);
goto clean_up;
}

rproc->state = RPROC_RUNNING;

dev_info(dev, "remote processor %s is now up\n", rproc->name);

return 0;

clean_up:
rproc_resource_cleanup(rproc);
rproc_disable_iommu(rproc);
return ret;
}

/*
* take a firmware and look for virtio devices to register.
*
* Note: this function is called asynchronously upon registration of the
* remote processor (so we must wait until it completes before we try
* to unregister the device. one other option is just to use kref here,
* that might be cleaner).
*/
static void rproc_fw_config_virtio(const struct firmware *fw, void *context)
{
struct rproc *rproc = context;
struct resource_table *table;
int ret, tablesz;

if (rproc_fw_sanity_check(rproc, fw) < 0)
goto out;

/* look for the resource table */
table = rproc_find_rsc_table(rproc, fw, &tablesz);
if (!table)
goto out;

/* look for virtio devices and register them */
ret = rproc_handle_virtio_rsc(rproc, table, tablesz);
if (ret)
goto out;

out:
release_firmware(fw);
/* allow rproc_del() contexts, if any, to proceed */
complete_all(&rproc->firmware_loading_complete);
}

/**
* rproc_boot() - boot a remote processor
* @rproc: handle of a remote processor
*
* Boot a remote processor (i.e. load its firmware, power it on, ...).
*
* If the remote processor is already powered on, this function immediately
* returns (successfully).
*
* Returns 0 on success, and an appropriate error value otherwise.
*/
int rproc_boot(struct rproc *rproc)
{
const struct firmware *firmware_p;
struct device *dev;
int ret;

if (!rproc) {
pr_err("invalid rproc handle\n");
return -EINVAL;
}

dev = &rproc->dev;

ret = mutex_lock_interruptible(&rproc->lock);
if (ret) {
dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret);
return ret;
}

/* loading a firmware is required */
if (!rproc->firmware) {
dev_err(dev, "%s: no firmware to load\n", __func__);
ret = -EINVAL;
goto unlock_mutex;
}

/* prevent underlying implementation from being removed */
if (!try_module_get(dev->parent->driver->owner)) {
dev_err(dev, "%s: can't get owner\n", __func__);
ret = -EINVAL;
goto unlock_mutex;
}

/* skip the boot process if rproc is already powered up */
if (atomic_inc_return(&rproc->power) > 1) {
ret = 0;
goto unlock_mutex;
}

dev_info(dev, "powering up %s\n", rproc->name);

/* load firmware */
ret = request_firmware(&firmware_p, rproc->firmware, dev);
if (ret < 0) {
dev_err(dev, "request_firmware failed: %d\n", ret);
goto downref_rproc;
}

ret = rproc_fw_boot(rproc, firmware_p);

release_firmware(firmware_p);

downref_rproc:
if (ret) {
module_put(dev->parent->driver->owner);
atomic_dec(&rproc->power);
}
unlock_mutex:
mutex_unlock(&rproc->lock);
return ret;
}
EXPORT_SYMBOL(rproc_boot);

/**
* rproc_shutdown() - power off the remote processor
* @rproc: the remote processor
*
* Power off a remote processor (previously booted with rproc_boot()).
*
* In case @rproc is still being used by an additional user(s), then
* this function will just decrement the power refcount and exit,
* without really powering off the device.
*
* Every call to rproc_boot() must (eventually) be accompanied by a call
* to rproc_shutdown(). Calling rproc_shutdown() redundantly is a bug.
*
* Notes:
* - we're not decrementing the rproc's refcount, only the power refcount.
* which means that the @rproc handle stays valid even after rproc_shutdown()
* returns, and users can still use it with a subsequent rproc_boot(), if
* needed.
*/
void rproc_shutdown(struct rproc *rproc)
{
struct device *dev = &rproc->dev;
int ret;

ret = mutex_lock_interruptible(&rproc->lock);
if (ret) {
dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, ret);
return;
}

/* if the remote proc is still needed, bail out */
if (!atomic_dec_and_test(&rproc->power))
goto out;

/* power off the remote processor */
ret = rproc->ops->stop(rproc);
if (ret) {
atomic_inc(&rproc->power);
dev_err(dev, "can't stop rproc: %d\n", ret);
goto out;
}

/* clean up all acquired resources */
rproc_resource_cleanup(rproc);

rproc_disable_iommu(rproc);

rproc->state = RPROC_OFFLINE;

dev_info(dev, "stopped remote processor %s\n", rproc->name);

out:
mutex_unlock(&rproc->lock);
if (!ret)
module_put(dev->parent->driver->owner);
}
EXPORT_SYMBOL(rproc_shutdown);

/**
* rproc_add() - register a remote processor
* @rproc: the remote processor handle to register
*
* Registers @rproc with the remoteproc framework, after it has been
* allocated with rproc_alloc().
*
* This is called by the platform-specific rproc implementation, whenever
* a new remote processor device is probed.
*
* Returns 0 on success and an appropriate error code otherwise.
*
* Note: this function initiates an asynchronous firmware loading
* context, which will look for virtio devices supported by the rproc's
* firmware.
*
* If found, those virtio devices will be created and added, so as a result
* of registering this remote processor, additional virtio drivers might be
* probed.
*/
int rproc_add(struct rproc *rproc)
{
struct device *dev = &rproc->dev;
int ret = 0;

ret = device_add(dev);
if (ret < 0)
return ret;

dev_info(dev, "%s is available\n", rproc->name);

dev_info(dev, "Note: remoteproc is still under development and considered experimental.\n");
dev_info(dev, "THE BINARY FORMAT IS NOT YET FINALIZED, and backward compatibility isn't yet guaranteed.\n");

/* create debugfs entries */
rproc_create_debug_dir(rproc);

/* rproc_del() calls must wait until async loader completes */
init_completion(&rproc->firmware_loading_complete);

/*
* We must retrieve early virtio configuration info from
* the firmware (e.g. whether to register a virtio device,
* what virtio features does it support, ...).
*
* We're initiating an asynchronous firmware loading, so we can
* be built-in kernel code, without hanging the boot process.
*/
ret = request_firmware_nowait(THIS_MODULE, FW_ACTION_HOTPLUG,
rproc->firmware, dev, GFP_KERNEL,
rproc, rproc_fw_config_virtio);
if (ret < 0) {
dev_err(dev, "request_firmware_nowait failed: %d\n", ret);
complete_all(&rproc->firmware_loading_complete);
}

return ret;
}
EXPORT_SYMBOL(rproc_add);

/**
* rproc_type_release() - release a remote processor instance
* @dev: the rproc's device
*
* This function should _never_ be called directly.
*
* It will be called by the driver core when no one holds a valid pointer
* to @dev anymore.
*/
static void rproc_type_release(struct device *dev)
{
struct rproc *rproc = container_of(dev, struct rproc, dev);

dev_info(&rproc->dev, "releasing %s\n", rproc->name);

rproc_delete_debug_dir(rproc);

idr_remove_all(&rproc->notifyids);
idr_destroy(&rproc->notifyids);

if (rproc->index >= 0)
ida_simple_remove(&rproc_dev_index, rproc->index);

kfree(rproc);
}

static struct device_type rproc_type = {
.name = "remoteproc",
.release = rproc_type_release,
};

/**
* rproc_alloc() - allocate a remote processor handle
* @dev: the underlying device
* @name: name of this remote processor
* @ops: platform-specific handlers (mainly start/stop)
* @firmware: name of firmware file to load
* @len: length of private data needed by the rproc driver (in bytes)
*
* Allocates a new remote processor handle, but does not register
* it yet.
*
* This function should be used by rproc implementations during initialization
* of the remote processor.
*
* After creating an rproc handle using this function, and when ready,
* implementations should then call rproc_add() to complete
* the registration of the remote processor.
*
* On success the new rproc is returned, and on failure, NULL.
*
* Note: _never_ directly deallocate @rproc, even if it was not registered
* yet. Instead, when you need to unroll rproc_alloc(), use rproc_put().
*/
struct rproc *rproc_alloc(struct device *dev, const char *name,
const struct rproc_ops *ops,
const char *firmware, int len)
{
struct rproc *rproc;

if (!dev || !name || !ops)
return NULL;

rproc = kzalloc(sizeof(struct rproc) + len, GFP_KERNEL);
if (!rproc) {
dev_err(dev, "%s: kzalloc failed\n", __func__);
return NULL;
}

rproc->name = name;
rproc->ops = ops;
rproc->firmware = firmware;
rproc->priv = &rproc[1];

device_initialize(&rproc->dev);
rproc->dev.parent = dev;
rproc->dev.type = &rproc_type;

/* Assign a unique device index and name */
rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
if (rproc->index < 0) {
dev_err(dev, "ida_simple_get failed: %d\n", rproc->index);
put_device(&rproc->dev);
return NULL;
}

dev_set_name(&rproc->dev, "remoteproc%d", rproc->index);

atomic_set(&rproc->power, 0);

/* Set ELF as the default fw_ops handler */
rproc->fw_ops = &rproc_elf_fw_ops;

mutex_init(&rproc->lock);

idr_init(&rproc->notifyids);

INIT_LIST_HEAD(&rproc->carveouts);
INIT_LIST_HEAD(&rproc->mappings);
INIT_LIST_HEAD(&rproc->traces);
INIT_LIST_HEAD(&rproc->rvdevs);

rproc->state = RPROC_OFFLINE;

return rproc;
}
EXPORT_SYMBOL(rproc_alloc);

/**
* rproc_put() - unroll rproc_alloc()
* @rproc: the remote processor handle
*
* This function decrements the rproc dev refcount.
*
* If no one holds any reference to rproc anymore, then its refcount would
* now drop to zero, and it would be freed.
*/
void rproc_put(struct rproc *rproc)
{
put_device(&rproc->dev);
}
EXPORT_SYMBOL(rproc_put);

/**
* rproc_del() - unregister a remote processor
* @rproc: rproc handle to unregister
*
* This function should be called when the platform specific rproc
* implementation decides to remove the rproc device. it should
* _only_ be called if a previous invocation of rproc_add()
* has completed successfully.
*
* After rproc_del() returns, @rproc isn't freed yet, because
* of the outstanding reference created by rproc_alloc. To decrement that
* one last refcount, one still needs to call rproc_put().
*
* Returns 0 on success and -EINVAL if @rproc isn't valid.
*/
int rproc_del(struct rproc *rproc)
{
struct rproc_vdev *rvdev, *tmp;

if (!rproc)
return -EINVAL;

/* if rproc is just being registered, wait */
wait_for_completion(&rproc->firmware_loading_complete);

/* clean up remote vdev entries */
list_for_each_entry_safe(rvdev, tmp, &rproc->rvdevs, node)
rproc_remove_virtio_dev(rvdev);

device_del(&rproc->dev);

return 0;
}
EXPORT_SYMBOL(rproc_del);

static int __init remoteproc_init(void)
{
rproc_init_debugfs();

return 0;
}
module_init(remoteproc_init);

static void __exit remoteproc_exit(void)
{
rproc_exit_debugfs();
}
module_exit(remoteproc_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Generic Remote Processor Framework");
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