linux/drivers/rpmsg/qcom_glink_smem.c
Bjorn Andersson 9d32497361 rpmsg: glink: smem: Ensure ordering during tx
Ensure the ordering of the fifo write and the update of the write index,
so that the index is not updated before the data has landed in the fifo.

Acked-By: Chris Lew <clew@codeaurora.org>
Reported-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2017-12-18 21:47:43 -08:00

318 lines
7.4 KiB
C

/*
* Copyright (c) 2016, Linaro Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only 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.
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/mfd/syscon.h>
#include <linux/slab.h>
#include <linux/rpmsg.h>
#include <linux/idr.h>
#include <linux/circ_buf.h>
#include <linux/soc/qcom/smem.h>
#include <linux/sizes.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <linux/workqueue.h>
#include <linux/list.h>
#include <linux/rpmsg/qcom_glink.h>
#include "qcom_glink_native.h"
#define FIFO_FULL_RESERVE 8
#define FIFO_ALIGNMENT 8
#define TX_BLOCKED_CMD_RESERVE 8 /* size of struct read_notif_request */
#define SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR 478
#define SMEM_GLINK_NATIVE_XPRT_FIFO_0 479
#define SMEM_GLINK_NATIVE_XPRT_FIFO_1 480
struct glink_smem_pipe {
struct qcom_glink_pipe native;
__le32 *tail;
__le32 *head;
void *fifo;
int remote_pid;
};
#define to_smem_pipe(p) container_of(p, struct glink_smem_pipe, native)
static size_t glink_smem_rx_avail(struct qcom_glink_pipe *np)
{
struct glink_smem_pipe *pipe = to_smem_pipe(np);
size_t len;
void *fifo;
u32 head;
u32 tail;
if (!pipe->fifo) {
fifo = qcom_smem_get(pipe->remote_pid,
SMEM_GLINK_NATIVE_XPRT_FIFO_1, &len);
if (IS_ERR(fifo)) {
pr_err("failed to acquire RX fifo handle: %ld\n",
PTR_ERR(fifo));
return 0;
}
pipe->fifo = fifo;
pipe->native.length = len;
}
head = le32_to_cpu(*pipe->head);
tail = le32_to_cpu(*pipe->tail);
if (head < tail)
return pipe->native.length - tail + head;
else
return head - tail;
}
static void glink_smem_rx_peak(struct qcom_glink_pipe *np,
void *data, unsigned int offset, size_t count)
{
struct glink_smem_pipe *pipe = to_smem_pipe(np);
size_t len;
u32 tail;
tail = le32_to_cpu(*pipe->tail);
tail += offset;
if (tail >= pipe->native.length)
tail -= pipe->native.length;
len = min_t(size_t, count, pipe->native.length - tail);
if (len) {
__ioread32_copy(data, pipe->fifo + tail,
len / sizeof(u32));
}
if (len != count) {
__ioread32_copy(data + len, pipe->fifo,
(count - len) / sizeof(u32));
}
}
static void glink_smem_rx_advance(struct qcom_glink_pipe *np,
size_t count)
{
struct glink_smem_pipe *pipe = to_smem_pipe(np);
u32 tail;
tail = le32_to_cpu(*pipe->tail);
tail += count;
if (tail > pipe->native.length)
tail -= pipe->native.length;
*pipe->tail = cpu_to_le32(tail);
}
static size_t glink_smem_tx_avail(struct qcom_glink_pipe *np)
{
struct glink_smem_pipe *pipe = to_smem_pipe(np);
u32 head;
u32 tail;
u32 avail;
head = le32_to_cpu(*pipe->head);
tail = le32_to_cpu(*pipe->tail);
if (tail <= head)
avail = pipe->native.length - head + tail;
else
avail = tail - head;
if (avail < (FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE))
avail = 0;
else
avail -= FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE;
return avail;
}
static unsigned int glink_smem_tx_write_one(struct glink_smem_pipe *pipe,
unsigned int head,
const void *data, size_t count)
{
size_t len;
len = min_t(size_t, count, pipe->native.length - head);
if (len)
memcpy(pipe->fifo + head, data, len);
if (len != count)
memcpy(pipe->fifo, data + len, count - len);
head += count;
if (head >= pipe->native.length)
head -= pipe->native.length;
return head;
}
static void glink_smem_tx_write(struct qcom_glink_pipe *glink_pipe,
const void *hdr, size_t hlen,
const void *data, size_t dlen)
{
struct glink_smem_pipe *pipe = to_smem_pipe(glink_pipe);
unsigned int head;
head = le32_to_cpu(*pipe->head);
head = glink_smem_tx_write_one(pipe, head, hdr, hlen);
head = glink_smem_tx_write_one(pipe, head, data, dlen);
/* Ensure head is always aligned to 8 bytes */
head = ALIGN(head, 8);
if (head >= pipe->native.length)
head -= pipe->native.length;
/* Ensure ordering of fifo and head update */
wmb();
*pipe->head = cpu_to_le32(head);
}
static void qcom_glink_smem_release(struct device *dev)
{
kfree(dev);
}
struct qcom_glink *qcom_glink_smem_register(struct device *parent,
struct device_node *node)
{
struct glink_smem_pipe *rx_pipe;
struct glink_smem_pipe *tx_pipe;
struct qcom_glink *glink;
struct device *dev;
u32 remote_pid;
__le32 *descs;
size_t size;
int ret;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return ERR_PTR(-ENOMEM);
dev->parent = parent;
dev->of_node = node;
dev->release = qcom_glink_smem_release;
dev_set_name(dev, "%s:%s", node->parent->name, node->name);
ret = device_register(dev);
if (ret) {
pr_err("failed to register glink edge\n");
return ERR_PTR(ret);
}
ret = of_property_read_u32(dev->of_node, "qcom,remote-pid",
&remote_pid);
if (ret) {
dev_err(dev, "failed to parse qcom,remote-pid\n");
goto err_put_dev;
}
rx_pipe = devm_kzalloc(dev, sizeof(*rx_pipe), GFP_KERNEL);
tx_pipe = devm_kzalloc(dev, sizeof(*tx_pipe), GFP_KERNEL);
if (!rx_pipe || !tx_pipe) {
ret = -ENOMEM;
goto err_put_dev;
}
ret = qcom_smem_alloc(remote_pid,
SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, 32);
if (ret && ret != -EEXIST) {
dev_err(dev, "failed to allocate glink descriptors\n");
goto err_put_dev;
}
descs = qcom_smem_get(remote_pid,
SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, &size);
if (IS_ERR(descs)) {
dev_err(dev, "failed to acquire xprt descriptor\n");
ret = PTR_ERR(descs);
goto err_put_dev;
}
if (size != 32) {
dev_err(dev, "glink descriptor of invalid size\n");
ret = -EINVAL;
goto err_put_dev;
}
tx_pipe->tail = &descs[0];
tx_pipe->head = &descs[1];
rx_pipe->tail = &descs[2];
rx_pipe->head = &descs[3];
ret = qcom_smem_alloc(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
SZ_16K);
if (ret && ret != -EEXIST) {
dev_err(dev, "failed to allocate TX fifo\n");
goto err_put_dev;
}
tx_pipe->fifo = qcom_smem_get(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
&tx_pipe->native.length);
if (IS_ERR(tx_pipe->fifo)) {
dev_err(dev, "failed to acquire TX fifo\n");
ret = PTR_ERR(tx_pipe->fifo);
goto err_put_dev;
}
rx_pipe->native.avail = glink_smem_rx_avail;
rx_pipe->native.peak = glink_smem_rx_peak;
rx_pipe->native.advance = glink_smem_rx_advance;
rx_pipe->remote_pid = remote_pid;
tx_pipe->native.avail = glink_smem_tx_avail;
tx_pipe->native.write = glink_smem_tx_write;
tx_pipe->remote_pid = remote_pid;
*rx_pipe->tail = 0;
*tx_pipe->head = 0;
glink = qcom_glink_native_probe(dev,
GLINK_FEATURE_INTENT_REUSE,
&rx_pipe->native, &tx_pipe->native,
false);
if (IS_ERR(glink)) {
ret = PTR_ERR(glink);
goto err_put_dev;
}
return glink;
err_put_dev:
put_device(dev);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(qcom_glink_smem_register);
void qcom_glink_smem_unregister(struct qcom_glink *glink)
{
qcom_glink_native_remove(glink);
qcom_glink_native_unregister(glink);
}
EXPORT_SYMBOL_GPL(qcom_glink_smem_unregister);
MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
MODULE_DESCRIPTION("Qualcomm GLINK SMEM driver");
MODULE_LICENSE("GPL v2");