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firmware: arm_ffa: Add support for MEM_* interfaces
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Most of the MEM_* APIs share the same parameters, so they can be
generalised. Currently only MEM_SHARE is implemented and the user space
interface for that is not added yet.

Link: https://lore.kernel.org/r/[email protected]
Tested-by: Jens Wiklander <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
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@sudeep-holla
sudeep-holla committed May 26, 2021
1 parent d0c0bce commit cc2195f
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199 changes: 199 additions & 0 deletions drivers/firmware/arm_ffa/driver.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,8 @@
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/uuid.h>

Expand Down Expand Up @@ -349,6 +351,192 @@ static int ffa_msg_send_direct_req(u16 src_id, u16 dst_id, bool mode_32bit,
return -EINVAL;
}

static int ffa_mem_first_frag(u32 func_id, phys_addr_t buf, u32 buf_sz,
u32 frag_len, u32 len, u64 *handle)
{
ffa_value_t ret;

invoke_ffa_fn((ffa_value_t){
.a0 = func_id, .a1 = len, .a2 = frag_len,
.a3 = buf, .a4 = buf_sz,
}, &ret);

while (ret.a0 == FFA_MEM_OP_PAUSE)
invoke_ffa_fn((ffa_value_t){
.a0 = FFA_MEM_OP_RESUME,
.a1 = ret.a1, .a2 = ret.a2,
}, &ret);

if (ret.a0 == FFA_ERROR)
return ffa_to_linux_errno((int)ret.a2);

if (ret.a0 != FFA_SUCCESS)
return -EOPNOTSUPP;

if (handle)
*handle = PACK_HANDLE(ret.a2, ret.a3);

return frag_len;
}

static int ffa_mem_next_frag(u64 handle, u32 frag_len)
{
ffa_value_t ret;

invoke_ffa_fn((ffa_value_t){
.a0 = FFA_MEM_FRAG_TX,
.a1 = HANDLE_LOW(handle), .a2 = HANDLE_HIGH(handle),
.a3 = frag_len,
}, &ret);

while (ret.a0 == FFA_MEM_OP_PAUSE)
invoke_ffa_fn((ffa_value_t){
.a0 = FFA_MEM_OP_RESUME,
.a1 = ret.a1, .a2 = ret.a2,
}, &ret);

if (ret.a0 == FFA_ERROR)
return ffa_to_linux_errno((int)ret.a2);

if (ret.a0 != FFA_MEM_FRAG_RX)
return -EOPNOTSUPP;

return ret.a3;
}

static int
ffa_transmit_fragment(u32 func_id, phys_addr_t buf, u32 buf_sz, u32 frag_len,
u32 len, u64 *handle, bool first)
{
if (!first)
return ffa_mem_next_frag(*handle, frag_len);

return ffa_mem_first_frag(func_id, buf, buf_sz, frag_len, len, handle);
}

static u32 ffa_get_num_pages_sg(struct scatterlist *sg)
{
u32 num_pages = 0;

do {
num_pages += sg->length / FFA_PAGE_SIZE;
} while ((sg = sg_next(sg)));

return num_pages;
}

static int
ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
struct ffa_mem_ops_args *args)
{
int rc = 0;
bool first = true;
phys_addr_t addr = 0;
struct ffa_composite_mem_region *composite;
struct ffa_mem_region_addr_range *constituents;
struct ffa_mem_region_attributes *ep_mem_access;
struct ffa_mem_region *mem_region = buffer;
u32 idx, frag_len, length, buf_sz = 0, num_entries = sg_nents(args->sg);

mem_region->tag = args->tag;
mem_region->flags = args->flags;
mem_region->sender_id = drv_info->vm_id;
mem_region->attributes = FFA_MEM_NORMAL | FFA_MEM_WRITE_BACK |
FFA_MEM_INNER_SHAREABLE;
ep_mem_access = &mem_region->ep_mem_access[0];

for (idx = 0; idx < args->nattrs; idx++, ep_mem_access++) {
ep_mem_access->receiver = args->attrs[idx].receiver;
ep_mem_access->attrs = args->attrs[idx].attrs;
ep_mem_access->composite_off = COMPOSITE_OFFSET(args->nattrs);
}
mem_region->ep_count = args->nattrs;

composite = buffer + COMPOSITE_OFFSET(args->nattrs);
composite->total_pg_cnt = ffa_get_num_pages_sg(args->sg);
composite->addr_range_cnt = num_entries;

length = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, num_entries);
frag_len = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, 0);
if (frag_len > max_fragsize)
return -ENXIO;

if (!args->use_txbuf) {
addr = virt_to_phys(buffer);
buf_sz = max_fragsize / FFA_PAGE_SIZE;
}

constituents = buffer + frag_len;
idx = 0;
do {
if (frag_len == max_fragsize) {
rc = ffa_transmit_fragment(func_id, addr, buf_sz,
frag_len, length,
&args->g_handle, first);
if (rc < 0)
return -ENXIO;

first = false;
idx = 0;
frag_len = 0;
constituents = buffer;
}

if ((void *)constituents - buffer > max_fragsize) {
pr_err("Memory Region Fragment > Tx Buffer size\n");
return -EFAULT;
}

constituents->address = sg_phys(args->sg);
constituents->pg_cnt = args->sg->length / FFA_PAGE_SIZE;
constituents++;
frag_len += sizeof(struct ffa_mem_region_addr_range);
} while ((args->sg = sg_next(args->sg)));

return ffa_transmit_fragment(func_id, addr, buf_sz, frag_len,
length, &args->g_handle, first);
}

static int ffa_memory_ops(u32 func_id, struct ffa_mem_ops_args *args)
{
int ret;
void *buffer;

if (!args->use_txbuf) {
buffer = alloc_pages_exact(RXTX_BUFFER_SIZE, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
} else {
buffer = drv_info->tx_buffer;
mutex_lock(&drv_info->tx_lock);
}

ret = ffa_setup_and_transmit(func_id, buffer, RXTX_BUFFER_SIZE, args);

if (args->use_txbuf)
mutex_unlock(&drv_info->tx_lock);
else
free_pages_exact(buffer, RXTX_BUFFER_SIZE);

return ret < 0 ? ret : 0;
}

static int ffa_memory_reclaim(u64 g_handle, u32 flags)
{
ffa_value_t ret;

invoke_ffa_fn((ffa_value_t){
.a0 = FFA_MEM_RECLAIM,
.a1 = HANDLE_LOW(g_handle), .a2 = HANDLE_HIGH(g_handle),
.a3 = flags,
}, &ret);

if (ret.a0 == FFA_ERROR)
return ffa_to_linux_errno((int)ret.a2);

return 0;
}

static u32 ffa_api_version_get(void)
{
return drv_info->version;
Expand Down Expand Up @@ -387,11 +575,22 @@ static int ffa_sync_send_receive(struct ffa_device *dev,
dev->mode_32bit, data);
}

static int
ffa_memory_share(struct ffa_device *dev, struct ffa_mem_ops_args *args)
{
if (dev->mode_32bit)
return ffa_memory_ops(FFA_MEM_SHARE, args);

return ffa_memory_ops(FFA_FN_NATIVE(MEM_SHARE), args);
}

static const struct ffa_dev_ops ffa_ops = {
.api_version_get = ffa_api_version_get,
.partition_info_get = ffa_partition_info_get,
.mode_32bit_set = ffa_mode_32bit_set,
.sync_send_receive = ffa_sync_send_receive,
.memory_reclaim = ffa_memory_reclaim,
.memory_share = ffa_memory_share,
};

const struct ffa_dev_ops *ffa_dev_ops_get(struct ffa_device *dev)
Expand Down
139 changes: 139 additions & 0 deletions include/linux/arm_ffa.h
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Original file line number Diff line number Diff line change
Expand Up @@ -116,13 +116,152 @@ struct ffa_send_direct_data {
unsigned long data4; /* w7/x7 */
};

struct ffa_mem_region_addr_range {
/* The base IPA of the constituent memory region, aligned to 4 kiB */
u64 address;
/* The number of 4 kiB pages in the constituent memory region. */
u32 pg_cnt;
u32 reserved;
};

struct ffa_composite_mem_region {
/*
* The total number of 4 kiB pages included in this memory region. This
* must be equal to the sum of page counts specified in each
* `struct ffa_mem_region_addr_range`.
*/
u32 total_pg_cnt;
/* The number of constituents included in this memory region range */
u32 addr_range_cnt;
u64 reserved;
/** An array of `addr_range_cnt` memory region constituents. */
struct ffa_mem_region_addr_range constituents[];
};

struct ffa_mem_region_attributes {
/* The ID of the VM to which the memory is being given or shared. */
u16 receiver;
/*
* The permissions with which the memory region should be mapped in the
* receiver's page table.
*/
#define FFA_MEM_EXEC BIT(3)
#define FFA_MEM_NO_EXEC BIT(2)
#define FFA_MEM_RW BIT(1)
#define FFA_MEM_RO BIT(0)
u8 attrs;
/*
* Flags used during FFA_MEM_RETRIEVE_REQ and FFA_MEM_RETRIEVE_RESP
* for memory regions with multiple borrowers.
*/
#define FFA_MEM_RETRIEVE_SELF_BORROWER BIT(0)
u8 flag;
u32 composite_off;
/*
* Offset in bytes from the start of the outer `ffa_memory_region` to
* an `struct ffa_mem_region_addr_range`.
*/
u64 reserved;
};

struct ffa_mem_region {
/* The ID of the VM/owner which originally sent the memory region */
u16 sender_id;
#define FFA_MEM_NORMAL BIT(5)
#define FFA_MEM_DEVICE BIT(4)

#define FFA_MEM_WRITE_BACK (3 << 2)
#define FFA_MEM_NON_CACHEABLE (1 << 2)

#define FFA_DEV_nGnRnE (0 << 2)
#define FFA_DEV_nGnRE (1 << 2)
#define FFA_DEV_nGRE (2 << 2)
#define FFA_DEV_GRE (3 << 2)

#define FFA_MEM_NON_SHAREABLE (0)
#define FFA_MEM_OUTER_SHAREABLE (2)
#define FFA_MEM_INNER_SHAREABLE (3)
u8 attributes;
u8 reserved_0;
/*
* Clear memory region contents after unmapping it from the sender and
* before mapping it for any receiver.
*/
#define FFA_MEM_CLEAR BIT(0)
/*
* Whether the hypervisor may time slice the memory sharing or retrieval
* operation.
*/
#define FFA_TIME_SLICE_ENABLE BIT(1)

#define FFA_MEM_RETRIEVE_TYPE_IN_RESP (0 << 3)
#define FFA_MEM_RETRIEVE_TYPE_SHARE (1 << 3)
#define FFA_MEM_RETRIEVE_TYPE_LEND (2 << 3)
#define FFA_MEM_RETRIEVE_TYPE_DONATE (3 << 3)

#define FFA_MEM_RETRIEVE_ADDR_ALIGN_HINT BIT(9)
#define FFA_MEM_RETRIEVE_ADDR_ALIGN(x) ((x) << 5)
/* Flags to control behaviour of the transaction. */
u32 flags;
#define HANDLE_LOW_MASK GENMASK_ULL(31, 0)
#define HANDLE_HIGH_MASK GENMASK_ULL(63, 32)
#define HANDLE_LOW(x) ((u32)(FIELD_GET(HANDLE_LOW_MASK, (x))))
#define HANDLE_HIGH(x) ((u32)(FIELD_GET(HANDLE_HIGH_MASK, (x))))

#define PACK_HANDLE(l, h) \
(FIELD_PREP(HANDLE_LOW_MASK, (l)) | FIELD_PREP(HANDLE_HIGH_MASK, (h)))
/*
* A globally-unique ID assigned by the hypervisor for a region
* of memory being sent between VMs.
*/
u64 handle;
/*
* An implementation defined value associated with the receiver and the
* memory region.
*/
u64 tag;
u32 reserved_1;
/*
* The number of `ffa_mem_region_attributes` entries included in this
* transaction.
*/
u32 ep_count;
/*
* An array of endpoint memory access descriptors.
* Each one specifies a memory region offset, an endpoint and the
* attributes with which this memory region should be mapped in that
* endpoint's page table.
*/
struct ffa_mem_region_attributes ep_mem_access[];
};

#define COMPOSITE_OFFSET(x) \
(offsetof(struct ffa_mem_region, ep_mem_access[x]))
#define CONSTITUENTS_OFFSET(x) \
(offsetof(struct ffa_composite_mem_region, constituents[x]))
#define COMPOSITE_CONSTITUENTS_OFFSET(x, y) \
(COMPOSITE_OFFSET(x) + CONSTITUENTS_OFFSET(y))

struct ffa_mem_ops_args {
bool use_txbuf;
u32 nattrs;
u32 flags;
u64 tag;
u64 g_handle;
struct scatterlist *sg;
struct ffa_mem_region_attributes *attrs;
};

struct ffa_dev_ops {
u32 (*api_version_get)(void);
int (*partition_info_get)(const char *uuid_str,
struct ffa_partition_info *buffer);
void (*mode_32bit_set)(struct ffa_device *dev);
int (*sync_send_receive)(struct ffa_device *dev,
struct ffa_send_direct_data *data);
int (*memory_reclaim)(u64 g_handle, u32 flags);
int (*memory_share)(struct ffa_device *dev,
struct ffa_mem_ops_args *args);
};

#endif /* _LINUX_ARM_FFA_H */

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