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SubjectRe: [PATCH v3] media: si2168: Refactor command setup code
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Hi Marc,

Replying inline.


On 04/07/2019 05.33, Marc Gonzalez wrote:
> Refactor the command setup code, and let the compiler determine
> the size of each command.
>
> Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
> ---
> Changes from v1:
> - Use a real function to populate struct si2168_cmd *cmd, and a trivial
> macro wrapping it (macro because sizeof).
> Changes from v2:
> - Fix header mess
> - Add Jonathan's tag
> ---
> drivers/media/dvb-frontends/si2168.c | 146 +++++++++------------------
> 1 file changed, 45 insertions(+), 101 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
> index c64b360ce6b5..5e81e076369c 100644
> --- a/drivers/media/dvb-frontends/si2168.c
> +++ b/drivers/media/dvb-frontends/si2168.c
> @@ -12,6 +12,16 @@
>
> static const struct dvb_frontend_ops si2168_ops;
>
> +static void cmd_setup(struct si2168_cmd *cmd, char *args, int wlen, int rlen)
> +{
> + memcpy(cmd->args, args, wlen);
> + cmd->wlen = wlen;
> + cmd->rlen = rlen;
> +}
> +


struct si2168_cmd.args is u8, not char. I also think const should apply
to the pointer.


> +#define CMD_SETUP(cmd, args, rlen) \
> + cmd_setup(cmd, args, sizeof(args) - 1, rlen)
> +


This is only a valid helper if args is a null terminated string. It just
so happens that every instance in this driver is, but that could be a
silent pitfall if someone used a u8 array with this macro.

Otherwise I'm ok with the refactoring.

Regards,

Brad




> /* execute firmware command */
> static int si2168_cmd_execute(struct i2c_client *client, struct si2168_cmd *cmd)
> {
> @@ -84,15 +94,13 @@ static int si2168_ts_bus_ctrl(struct dvb_frontend *fe, int acquire)
> dev_dbg(&client->dev, "%s acquire: %d\n", __func__, acquire);
>
> /* set TS_MODE property */
> - memcpy(cmd.args, "\x14\x00\x01\x10\x10\x00", 6);
> + CMD_SETUP(&cmd, "\x14\x00\x01\x10\x10\x00", 4);
> if (acquire)
> cmd.args[4] |= dev->ts_mode;
> else
> cmd.args[4] |= SI2168_TS_TRISTATE;
> if (dev->ts_clock_gapped)
> cmd.args[4] |= 0x40;
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> ret = si2168_cmd_execute(client, &cmd);
>
> return ret;
> @@ -116,19 +124,13 @@ static int si2168_read_status(struct dvb_frontend *fe, enum fe_status *status)
>
> switch (c->delivery_system) {
> case SYS_DVBT:
> - memcpy(cmd.args, "\xa0\x01", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 13;
> + CMD_SETUP(&cmd, "\xa0\x01", 13);
> break;
> case SYS_DVBC_ANNEX_A:
> - memcpy(cmd.args, "\x90\x01", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 9;
> + CMD_SETUP(&cmd, "\x90\x01", 9);
> break;
> case SYS_DVBT2:
> - memcpy(cmd.args, "\x50\x01", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 14;
> + CMD_SETUP(&cmd, "\x50\x01", 14);
> break;
> default:
> ret = -EINVAL;
> @@ -165,9 +167,7 @@ static int si2168_read_status(struct dvb_frontend *fe, enum fe_status *status)
>
> /* BER */
> if (*status & FE_HAS_VITERBI) {
> - memcpy(cmd.args, "\x82\x00", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 3;
> + CMD_SETUP(&cmd, "\x82\x00", 3);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -198,9 +198,7 @@ static int si2168_read_status(struct dvb_frontend *fe, enum fe_status *status)
>
> /* UCB */
> if (*status & FE_HAS_SYNC) {
> - memcpy(cmd.args, "\x84\x01", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 3;
> + CMD_SETUP(&cmd, "\x84\x01", 3);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -286,22 +284,18 @@ static int si2168_set_frontend(struct dvb_frontend *fe)
> goto err;
> }
>
> - memcpy(cmd.args, "\x88\x02\x02\x02\x02", 5);
> - cmd.wlen = 5;
> - cmd.rlen = 5;
> + CMD_SETUP(&cmd, "\x88\x02\x02\x02\x02", 5);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> /* that has no big effect */
> if (c->delivery_system == SYS_DVBT)
> - memcpy(cmd.args, "\x89\x21\x06\x11\xff\x98", 6);
> + CMD_SETUP(&cmd, "\x89\x21\x06\x11\xff\x98", 3);
> else if (c->delivery_system == SYS_DVBC_ANNEX_A)
> - memcpy(cmd.args, "\x89\x21\x06\x11\x89\xf0", 6);
> + CMD_SETUP(&cmd, "\x89\x21\x06\x11\x89\xf0", 3);
> else if (c->delivery_system == SYS_DVBT2)
> - memcpy(cmd.args, "\x89\x21\x06\x11\x89\x20", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 3;
> + CMD_SETUP(&cmd, "\x89\x21\x06\x11\x89\x20", 3);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -318,103 +312,77 @@ static int si2168_set_frontend(struct dvb_frontend *fe)
> goto err;
> }
>
> - memcpy(cmd.args, "\x51\x03", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 12;
> + CMD_SETUP(&cmd, "\x51\x03", 12);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x12\x08\x04", 3);
> - cmd.wlen = 3;
> - cmd.rlen = 3;
> + CMD_SETUP(&cmd, "\x12\x08\x04", 3);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x0c\x10\x12\x00", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x0c\x10\x12\x00", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x06\x10\x24\x00", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x06\x10\x24\x00", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x07\x10\x00\x24", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x07\x10\x00\x24", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x0a\x10\x00\x00", 6);
> + CMD_SETUP(&cmd, "\x14\x00\x0a\x10\x00\x00", 4);
> cmd.args[4] = delivery_system | bandwidth;
> if (dev->spectral_inversion)
> cmd.args[5] |= 1;
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> /* set DVB-C symbol rate */
> if (c->delivery_system == SYS_DVBC_ANNEX_A) {
> - memcpy(cmd.args, "\x14\x00\x02\x11", 4);
> + CMD_SETUP(&cmd, "\x14\x00\x02\x11\x00\x00", 4);
> cmd.args[4] = ((c->symbol_rate / 1000) >> 0) & 0xff;
> cmd.args[5] = ((c->symbol_rate / 1000) >> 8) & 0xff;
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> }
>
> - memcpy(cmd.args, "\x14\x00\x0f\x10\x10\x00", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x0f\x10\x10\x00", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x09\x10\xe3\x08", 6);
> + CMD_SETUP(&cmd, "\x14\x00\x09\x10\xe3\x08", 4);
> cmd.args[5] |= dev->ts_clock_inv ? 0x00 : 0x10;
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x08\x10\xd7\x05", 6);
> + CMD_SETUP(&cmd, "\x14\x00\x08\x10\xd7\x05", 4);
> cmd.args[5] |= dev->ts_clock_inv ? 0x00 : 0x10;
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x01\x12\x00\x00", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x01\x12\x00\x00", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x14\x00\x01\x03\x0c\x00", 6);
> - cmd.wlen = 6;
> - cmd.rlen = 4;
> + CMD_SETUP(&cmd, "\x14\x00\x01\x03\x0c\x00", 4);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> - memcpy(cmd.args, "\x85", 1);
> - cmd.wlen = 1;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\x85", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -444,26 +412,20 @@ static int si2168_init(struct dvb_frontend *fe)
> dev_dbg(&client->dev, "\n");
>
> /* initialize */
> - memcpy(cmd.args, "\xc0\x12\x00\x0c\x00\x0d\x16\x00\x00\x00\x00\x00\x00", 13);
> - cmd.wlen = 13;
> - cmd.rlen = 0;
> + CMD_SETUP(&cmd, "\xc0\x12\x00\x0c\x00\x0d\x16\x00\x00\x00\x00\x00\x00", 0);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> if (dev->warm) {
> /* resume */
> - memcpy(cmd.args, "\xc0\x06\x08\x0f\x00\x20\x21\x01", 8);
> - cmd.wlen = 8;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\xc0\x06\x08\x0f\x00\x20\x21\x01", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> udelay(100);
> - memcpy(cmd.args, "\x85", 1);
> - cmd.wlen = 1;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\x85", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -472,9 +434,7 @@ static int si2168_init(struct dvb_frontend *fe)
> }
>
> /* power up */
> - memcpy(cmd.args, "\xc0\x06\x01\x0f\x00\x20\x20\x01", 8);
> - cmd.wlen = 8;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\xc0\x06\x01\x0f\x00\x20\x20\x01", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -542,17 +502,13 @@ static int si2168_init(struct dvb_frontend *fe)
>
> release_firmware(fw);
>
> - memcpy(cmd.args, "\x01\x01", 2);
> - cmd.wlen = 2;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\x01\x01", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
>
> /* query firmware version */
> - memcpy(cmd.args, "\x11", 1);
> - cmd.wlen = 1;
> - cmd.rlen = 10;
> + CMD_SETUP(&cmd, "\x11", 10);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -610,9 +566,7 @@ static int si2168_sleep(struct dvb_frontend *fe)
> if (dev->version > ('B' << 24 | 4 << 16 | 0 << 8 | 11 << 0))
> dev->warm = false;
>
> - memcpy(cmd.args, "\x13", 1);
> - cmd.wlen = 1;
> - cmd.rlen = 0;
> + CMD_SETUP(&cmd, "\x13", 0);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -638,9 +592,7 @@ static int si2168_select(struct i2c_mux_core *muxc, u32 chan)
> struct si2168_cmd cmd;
>
> /* open I2C gate */
> - memcpy(cmd.args, "\xc0\x0d\x01", 3);
> - cmd.wlen = 3;
> - cmd.rlen = 0;
> + CMD_SETUP(&cmd, "\xc0\x0d\x01", 0);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -658,9 +610,7 @@ static int si2168_deselect(struct i2c_mux_core *muxc, u32 chan)
> struct si2168_cmd cmd;
>
> /* close I2C gate */
> - memcpy(cmd.args, "\xc0\x0d\x00", 3);
> - cmd.wlen = 3;
> - cmd.rlen = 0;
> + CMD_SETUP(&cmd, "\xc0\x0d\x00", 0);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err;
> @@ -753,25 +703,19 @@ static int si2168_probe(struct i2c_client *client,
> mutex_init(&dev->i2c_mutex);
>
> /* Initialize */
> - memcpy(cmd.args, "\xc0\x12\x00\x0c\x00\x0d\x16\x00\x00\x00\x00\x00\x00", 13);
> - cmd.wlen = 13;
> - cmd.rlen = 0;
> + CMD_SETUP(&cmd, "\xc0\x12\x00\x0c\x00\x0d\x16\x00\x00\x00\x00\x00\x00", 0);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err_kfree;
>
> /* Power up */
> - memcpy(cmd.args, "\xc0\x06\x01\x0f\x00\x20\x20\x01", 8);
> - cmd.wlen = 8;
> - cmd.rlen = 1;
> + CMD_SETUP(&cmd, "\xc0\x06\x01\x0f\x00\x20\x20\x01", 1);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err_kfree;
>
> /* Query chip revision */
> - memcpy(cmd.args, "\x02", 1);
> - cmd.wlen = 1;
> - cmd.rlen = 13;
> + CMD_SETUP(&cmd, "\x02", 13);
> ret = si2168_cmd_execute(client, &cmd);
> if (ret)
> goto err_kfree;

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