[PATCH 4.9 099/153] w1: ds2490: USB transfer buffers need to be DMAable

Greg Kroah-Hartman
2017-03-10T09:22:42Z

From: Maciej S. Szmigiero <mail@maciej.szmigiero.name>

commit 61cd1b4cd1e8f7f7642ab64529d9bd52e8374641 upstream.

ds2490 driver was doing USB transfers from / to buffers on a stack.
This is not permitted and made the driver non-working with vmapped stacks.

Since all these transfers are done under the same bus_mutex lock we can
simply use shared buffers in a device private structure for two most common
of them.

While we are at it, let's also fix a comparison between int and size_t in
ds9490r_search() which made the driver spin in this function if state
register get requests were failing.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/w1/masters/ds2490.c | 142 ++++++++++++++++++++++++++------------------
1 file changed, 84 insertions(+), 58 deletions(-)

--- a/drivers/w1/masters/ds2490.c
+++ b/drivers/w1/masters/ds2490.c
@@ -153,6 +153,9 @@ struct ds_device
*/
u16 spu_bit;

+ u8 st_buf[ST_SIZE];
+ u8 byte_buf;
+
struct w1_bus_master master;
};

@@ -174,7 +177,6 @@ struct ds_status
u8 data_in_buffer_status;
u8 reserved1;
u8 reserved2;
-
};

static struct usb_device_id ds_id_table [] = {
@@ -244,28 +246,6 @@ static int ds_send_control(struct ds_dev
return err;
}

-static int ds_recv_status_nodump(struct ds_device *dev, struct ds_status *st,
- unsigned char *buf, int size)
-{
- int count, err;
-
- memset(st, 0, sizeof(*st));
-
- count = 0;
- err = usb_interrupt_msg(dev->udev, usb_rcvintpipe(dev->udev,
- dev->ep[EP_STATUS]), buf, size, &count, 1000);
- if (err < 0) {
- pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n",
- dev->ep[EP_STATUS], err);
- return err;
- }
-
- if (count >= sizeof(*st))
- memcpy(st, buf, sizeof(*st));
-
- return count;
-}
-
static inline void ds_print_msg(unsigned char *buf, unsigned char *str, int off)
{
pr_info("%45s: %8x\n", str, buf[off]);
@@ -324,6 +304,35 @@ static void ds_dump_status(struct ds_dev
}
}

+static int ds_recv_status(struct ds_device *dev, struct ds_status *st,
+ bool dump)
+{
+ int count, err;
+
+ if (st)
+ memset(st, 0, sizeof(*st));
+
+ count = 0;
+ err = usb_interrupt_msg(dev->udev,
+ usb_rcvintpipe(dev->udev,
+ dev->ep[EP_STATUS]),
+ dev->st_buf, sizeof(dev->st_buf),
+ &count, 1000);
+ if (err < 0) {
+ pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n",
+ dev->ep[EP_STATUS], err);
+ return err;
+ }
+
+ if (dump)
+ ds_dump_status(dev, dev->st_buf, count);
+
+ if (st && count >= sizeof(*st))
+ memcpy(st, dev->st_buf, sizeof(*st));
+
+ return count;
+}
+
static void ds_reset_device(struct ds_device *dev)
{
ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
@@ -344,7 +353,6 @@ static void ds_reset_device(struct ds_de
static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size)
{
int count, err;
- struct ds_status st;

/* Careful on size. If size is less than what is available in
* the input buffer, the device fails the bulk transfer and
@@ -359,14 +367,9 @@ static int ds_recv_data(struct ds_device
err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]),
buf, size, &count, 1000);
if (err < 0) {
- u8 buf[ST_SIZE];
- int count;
-
pr_info("Clearing ep0x%x.\n", dev->ep[EP_DATA_IN]);
usb_clear_halt(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]));
-
- count = ds_recv_status_nodump(dev, &st, buf, sizeof(buf));
- ds_dump_status(dev, buf, count);
+ ds_recv_status(dev, NULL, true);
return err;
}

@@ -404,7 +407,6 @@ int ds_stop_pulse(struct ds_device *dev,
{
struct ds_status st;
int count = 0, err = 0;
- u8 buf[ST_SIZE];

do {
err = ds_send_control(dev, CTL_HALT_EXE_IDLE, 0);
@@ -413,7 +415,7 @@ int ds_stop_pulse(struct ds_device *dev,
err = ds_send_control(dev, CTL_RESUME_EXE, 0);
if (err)
break;
- err = ds_recv_status_nodump(dev, &st, buf, sizeof(buf));
+ err = ds_recv_status(dev, &st, false);
if (err)
break;

@@ -456,18 +458,17 @@ int ds_detect(struct ds_device *dev, str

static int ds_wait_status(struct ds_device *dev, struct ds_status *st)
{
- u8 buf[ST_SIZE];
int err, count = 0;

do {
st->status = 0;
- err = ds_recv_status_nodump(dev, st, buf, sizeof(buf));
+ err = ds_recv_status(dev, st, false);
#if 0
if (err >= 0) {
int i;
printk("0x%x: count=%d, status: ", dev->ep[EP_STATUS], err);
for (i=0; i<err; ++i)
- printk("%02x ", buf[i]);
+ printk("%02x ", dev->st_buf[i]);
printk("\n");
}
#endif
@@ -485,7 +486,7 @@ static int ds_wait_status(struct ds_devi
* can do something with it).
*/
if (err > 16 || count >= 100 || err < 0)
- ds_dump_status(dev, buf, err);
+ ds_dump_status(dev, dev->st_buf, err);

/* Extended data isn't an error. Well, a short is, but the dump
* would have already told the user that and we can't do anything
@@ -608,7 +609,6 @@ static int ds_write_byte(struct ds_devic
{
int err;
struct ds_status st;
- u8 rbyte;

err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM | dev->spu_bit, byte);
if (err)
@@ -621,11 +621,11 @@ static int ds_write_byte(struct ds_devic
if (err)
return err;

- err = ds_recv_data(dev, &rbyte, sizeof(rbyte));
+ err = ds_recv_data(dev, &dev->byte_buf, 1);
if (err < 0)
return err;

- return !(byte == rbyte);
+ return !(byte == dev->byte_buf);
}

static int ds_read_byte(struct ds_device *dev, u8 *byte)
@@ -712,7 +712,6 @@ static void ds9490r_search(void *data, s
int err;
u16 value, index;
struct ds_status st;
- u8 st_buf[ST_SIZE];
int search_limit;
int found = 0;
int i;
@@ -724,7 +723,12 @@ static void ds9490r_search(void *data, s
/* FIFO 128 bytes, bulk packet size 64, read a multiple of the
* packet size.
*/
- u64 buf[2*64/8];
+ const size_t bufsize = 2 * 64;
+ u64 *buf;
+
+ buf = kmalloc(bufsize, GFP_KERNEL);
+ if (!buf)
+ return;

mutex_lock(&master->bus_mutex);

@@ -745,10 +749,9 @@ static void ds9490r_search(void *data, s
do {
schedule_timeout(jtime);

- if (ds_recv_status_nodump(dev, &st, st_buf, sizeof(st_buf)) <
- sizeof(st)) {
+ err = ds_recv_status(dev, &st, false);
+ if (err < 0 || err < sizeof(st))
break;
- }

if (st.data_in_buffer_status) {
/* Bulk in can receive partial ids, but when it does
@@ -758,7 +761,7 @@ static void ds9490r_search(void *data, s
* bulk without first checking if status says there
* is data to read.
*/
- err = ds_recv_data(dev, (u8 *)buf, sizeof(buf));
+ err = ds_recv_data(dev, (u8 *)buf, bufsize);
if (err < 0)
break;
for (i = 0; i < err/8; ++i) {
@@ -794,9 +797,14 @@ static void ds9490r_search(void *data, s
}
search_out:
mutex_unlock(&master->bus_mutex);
+ kfree(buf);
}

#if 0
+/*
+ * FIXME: if this disabled code is ever used in the future all ds_send_data()
+ * calls must be changed to use a DMAable buffer.
+ */
static int ds_match_access(struct ds_device *dev, u64 init)
{
int err;
@@ -845,13 +853,12 @@ static int ds_set_path(struct ds_device

static u8 ds9490r_touch_bit(void *data, u8 bit)
{
- u8 ret;
struct ds_device *dev = data;

- if (ds_touch_bit(dev, bit, &ret))
+ if (ds_touch_bit(dev, bit, &dev->byte_buf))
return 0;

- return ret;
+ return dev->byte_buf;
}

#if 0
@@ -866,13 +873,12 @@ static u8 ds9490r_read_bit(void *data)
{
struct ds_device *dev = data;
int err;
- u8 bit = 0;

- err = ds_touch_bit(dev, 1, &bit);
+ err = ds_touch_bit(dev, 1, &dev->byte_buf);
if (err)
return 0;

- return bit & 1;
+ return dev->byte_buf & 1;
}
#endif

@@ -887,32 +893,52 @@ static u8 ds9490r_read_byte(void *data)
{
struct ds_device *dev = data;
int err;
- u8 byte = 0;

- err = ds_read_byte(dev, &byte);
+ err = ds_read_byte(dev, &dev->byte_buf);
if (err)
return 0;

- return byte;
+ return dev->byte_buf;
}

static void ds9490r_write_block(void *data, const u8 *buf, int len)
{
struct ds_device *dev = data;
+ u8 *tbuf;
+
+ if (len <= 0)
+ return;
+
+ tbuf = kmalloc(len, GFP_KERNEL);
+ if (!tbuf)
+ return;
+
+ memcpy(tbuf, buf, len);
+ ds_write_block(dev, tbuf, len);

- ds_write_block(dev, (u8 *)buf, len);
+ kfree(tbuf);
}

static u8 ds9490r_read_block(void *data, u8 *buf, int len)
{
struct ds_device *dev = data;
int err;
+ u8 *tbuf;

- err = ds_read_block(dev, buf, len);
- if (err < 0)
+ if (len <= 0)
+ return 0;
+
+ tbuf = kmalloc(len, GFP_KERNEL);
+ if (!tbuf)
return 0;

- return len;
+ err = ds_read_block(dev, tbuf, len);
+ if (err >= 0)
+ memcpy(buf, tbuf, len);
+
+ kfree(tbuf);
+
+ return err >= 0 ? len : 0;
}

static u8 ds9490r_reset(void *data)