Re: [PATCH 20/26] pctv452e: don't do DMA on stack
On Fri, 7 Oct 2016 14:24:30 -0300
Mauro Carvalho Chehab wrote:
> The USB control messages require DMA to work. We cannot pass
> a stack-allocated buffer, as it is not warranted that the
> stack would be into a DMA enabled area.
>
> Signed-off-by: Mauro Carvalho Chehab
> ---
> drivers/media/usb/dvb-usb/pctv452e.c | 110
> ++- 1 file changed, 58 insertions(+),
> 52 deletions(-)
>
> diff --git a/drivers/media/usb/dvb-usb/pctv452e.c
> b/drivers/media/usb/dvb-usb/pctv452e.c index
> c05de1b088a4..855fe9d34b59 100644 ---
> a/drivers/media/usb/dvb-usb/pctv452e.c +++
> b/drivers/media/usb/dvb-usb/pctv452e.c @@ -97,13 +97,14 @@ struct
> pctv452e_state { u8 c; /* transaction counter, wraps
> around... */ u8 initialized; /* set to 1 if 0x15 has been sent */
> u16 last_rc_key;
> +
> + unsigned char data[80];
> };
>
> static int tt3650_ci_msg(struct dvb_usb_device *d, u8 cmd, u8 *data,
>unsigned int write_len, unsigned int
> read_len) {
> struct pctv452e_state *state = (struct pctv452e_state
> *)d->priv;
> - u8 buf[64];
> u8 id;
> unsigned int rlen;
> int ret;
> @@ -114,30 +115,30 @@ static int tt3650_ci_msg(struct dvb_usb_device
> *d, u8 cmd, u8 *data,
> id = state->c++;
>
> - buf[0] = SYNC_BYTE_OUT;
> - buf[1] = id;
> - buf[2] = cmd;
> - buf[3] = write_len;
> + state->data[0] = SYNC_BYTE_OUT;
> + state->data[1] = id;
> + state->data[2] = cmd;
> + state->data[3] = write_len;
>
> - memcpy(buf + 4, data, write_len);
> + memcpy(state->data + 4, data, write_len);
>
> rlen = (read_len > 0) ? 64 : 0;
> - ret = dvb_usb_generic_rw(d, buf, 4 + write_len,
> - buf, rlen, /* delay_ms */ 0);
> + ret = dvb_usb_generic_rw(d, state->data, 4 + write_len,
> + state->data, rlen, /* delay_ms */
> 0); if (0 != ret)
> goto failed;
>
> ret = -EIO;
> - if (SYNC_BYTE_IN != buf[0] || id != buf[1])
> + if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
> goto failed;
>
> - memcpy(data, buf + 4, read_len);
> + memcpy(data, state->data + 4, read_len);
>
> return 0;
>
> failed:
> err("CI error %d; %02X %02X %02X -> %*ph.",
> - ret, SYNC_BYTE_OUT, id, cmd, 3, buf);
> + ret, SYNC_BYTE_OUT, id, cmd, 3, state->data);
>
> return ret;
> }
> @@ -405,7 +406,6 @@ static int pctv452e_i2c_msg(struct dvb_usb_device
> *d, u8 addr, u8 *rcv_buf, u8 rcv_len)
> {
> struct pctv452e_state *state = (struct pctv452e_state
> *)d->priv;
> - u8 buf[64];
> u8 id;
> int ret;
>
> @@ -415,42 +415,40 @@ static int pctv452e_i2c_msg(struct
> dvb_usb_device *d, u8 addr, if (snd_len > 64 - 7 || rcv_len > 64 - 7)
> goto failed;
>
> - buf[0] = SYNC_BYTE_OUT;
> - buf[1] = id;
> - buf[2] = PCTV_CMD_I2C;
> - buf[3] = snd_len + 3;
> - buf[4] = addr << 1;
> - buf[5] = snd_len;
> - buf[6] = rcv_len;
> + state->data[0] = SYNC_BYTE_OUT;
> + state->data[1] = id;
> + state->data[2] = PCTV_CMD_I2C;
> + state->data[3] = snd_len + 3;
> + state->data[4] = addr << 1;
> + state->data[5] = snd_len;
> + state->data[6] = rcv_len;
>
> - memcpy(buf + 7, snd_buf, snd_len);
> + memcpy(state->data + 7, snd_buf, snd_len);
>
> - ret = dvb_usb_generic_rw(d, buf, 7 + snd_len,
> - buf, /* rcv_len */ 64,
> + ret = dvb_usb_generic_rw(d, state->data, 7 + snd_len,
> + state->data, /* rcv_len */ 64,
> /* delay_ms */ 0);
> if (ret < 0)
> goto failed;
>
> /* TT USB protocol error. */
> ret = -EIO;
> - if (SYNC_BYTE_IN != buf[0] || id != buf[1])
> + if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
> goto failed;
>
> /* I2C device didn't respond as expected. */
> ret = -EREMOTEIO;
> - if (buf[5] < snd_len || buf[6] < rcv_len)
> + if (state->data[5] < snd_len || state->data[6] < rcv_len)
> goto failed;
>
> - memcpy(rcv_buf, buf + 7, rcv_len);
> + memcpy(rcv_buf, state->data + 7, rcv_len);
>
> return rcv_len;
>
> failed:
> - err("I2C error %d; %02X %02X %02X %02X %02X -> "
> - "%02X %02X %02X %02X %02X.",
> + err("I2C error %d; %02X %02X %02X %02X %02X -> %*ph",
>ret, SYNC_BYTE_OUT, id, addr << 1, snd_len, rcv_len,
> - buf[0], buf[1], buf[4], buf[5], buf[6]);
> -
> + 7, state->data);
> return ret;
> }
>
> @@ -499,8 +497,7 @@ static u32 pctv452e_i2c_func(struct i2c_adapter
> *adapter) static int pctv452e_power_ctrl(struct dvb_usb_device *d,
> int i) {
> struct pctv452e_state *state = (struct pctv452e_state
> *)d->priv;
> - u8 b0[] = { 0xaa, 0, PCTV_CMD_RESET, 1, 0 };
> - u8 rx[PCTV_
[PATCH 20/26] pctv452e: don't do DMA on stack
The USB control messages require DMA to work. We cannot pass
a stack-allocated buffer, as it is not warranted that the
stack would be into a DMA enabled area.
Signed-off-by: Mauro Carvalho Chehab
---
drivers/media/usb/dvb-usb/pctv452e.c | 110 ++-
1 file changed, 58 insertions(+), 52 deletions(-)
diff --git a/drivers/media/usb/dvb-usb/pctv452e.c
b/drivers/media/usb/dvb-usb/pctv452e.c
index c05de1b088a4..855fe9d34b59 100644
--- a/drivers/media/usb/dvb-usb/pctv452e.c
+++ b/drivers/media/usb/dvb-usb/pctv452e.c
@@ -97,13 +97,14 @@ struct pctv452e_state {
u8 c; /* transaction counter, wraps around... */
u8 initialized; /* set to 1 if 0x15 has been sent */
u16 last_rc_key;
+
+ unsigned char data[80];
};
static int tt3650_ci_msg(struct dvb_usb_device *d, u8 cmd, u8 *data,
unsigned int write_len, unsigned int read_len)
{
struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
- u8 buf[64];
u8 id;
unsigned int rlen;
int ret;
@@ -114,30 +115,30 @@ static int tt3650_ci_msg(struct dvb_usb_device *d, u8
cmd, u8 *data,
id = state->c++;
- buf[0] = SYNC_BYTE_OUT;
- buf[1] = id;
- buf[2] = cmd;
- buf[3] = write_len;
+ state->data[0] = SYNC_BYTE_OUT;
+ state->data[1] = id;
+ state->data[2] = cmd;
+ state->data[3] = write_len;
- memcpy(buf + 4, data, write_len);
+ memcpy(state->data + 4, data, write_len);
rlen = (read_len > 0) ? 64 : 0;
- ret = dvb_usb_generic_rw(d, buf, 4 + write_len,
- buf, rlen, /* delay_ms */ 0);
+ ret = dvb_usb_generic_rw(d, state->data, 4 + write_len,
+ state->data, rlen, /* delay_ms */ 0);
if (0 != ret)
goto failed;
ret = -EIO;
- if (SYNC_BYTE_IN != buf[0] || id != buf[1])
+ if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
goto failed;
- memcpy(data, buf + 4, read_len);
+ memcpy(data, state->data + 4, read_len);
return 0;
failed:
err("CI error %d; %02X %02X %02X -> %*ph.",
-ret, SYNC_BYTE_OUT, id, cmd, 3, buf);
+ret, SYNC_BYTE_OUT, id, cmd, 3, state->data);
return ret;
}
@@ -405,7 +406,6 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u8
addr,
u8 *rcv_buf, u8 rcv_len)
{
struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
- u8 buf[64];
u8 id;
int ret;
@@ -415,42 +415,40 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u8
addr,
if (snd_len > 64 - 7 || rcv_len > 64 - 7)
goto failed;
- buf[0] = SYNC_BYTE_OUT;
- buf[1] = id;
- buf[2] = PCTV_CMD_I2C;
- buf[3] = snd_len + 3;
- buf[4] = addr << 1;
- buf[5] = snd_len;
- buf[6] = rcv_len;
+ state->data[0] = SYNC_BYTE_OUT;
+ state->data[1] = id;
+ state->data[2] = PCTV_CMD_I2C;
+ state->data[3] = snd_len + 3;
+ state->data[4] = addr << 1;
+ state->data[5] = snd_len;
+ state->data[6] = rcv_len;
- memcpy(buf + 7, snd_buf, snd_len);
+ memcpy(state->data + 7, snd_buf, snd_len);
- ret = dvb_usb_generic_rw(d, buf, 7 + snd_len,
- buf, /* rcv_len */ 64,
+ ret = dvb_usb_generic_rw(d, state->data, 7 + snd_len,
+ state->data, /* rcv_len */ 64,
/* delay_ms */ 0);
if (ret < 0)
goto failed;
/* TT USB protocol error. */
ret = -EIO;
- if (SYNC_BYTE_IN != buf[0] || id != buf[1])
+ if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
goto failed;
/* I2C device didn't respond as expected. */
ret = -EREMOTEIO;
- if (buf[5] < snd_len || buf[6] < rcv_len)
+ if (state->data[5] < snd_len || state->data[6] < rcv_len)
goto failed;
- memcpy(rcv_buf, buf + 7, rcv_len);
+ memcpy(rcv_buf, state->data + 7, rcv_len);
return rcv_len;
failed:
- err("I2C error %d; %02X %02X %02X %02X %02X -> "
-"%02X %02X %02X %02X %02X.",
+ err("I2C error %d; %02X %02X %02X %02X %02X -> %*ph",
ret, SYNC_BYTE_OUT, id, addr << 1, snd_len, rcv_len,
-buf[0], buf[1], buf[4], buf[5], buf[6]);
-
+7, state->data);
return ret;
}
@@ -499,8 +497,7 @@ static u32 pctv452e_i2c_func(struct i2c_adapter *adapter)
static int pctv452e_power_ctrl(struct dvb_usb_device *d, int i)
{
struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
- u8 b0[] = { 0xaa, 0, PCTV_CMD_RESET, 1, 0 };
- u8 rx[PCTV_ANSWER_LEN];
+ u8 *rx;
int ret;
info("%s: %d\n", __func__, i);
@@ -511,6 +508,10 @@ static i
