[PATCH 6/6] firedtv: reduce memset()s

From: Stefan Richter
Date: Wed Nov 18 2009 - 14:03:54 EST

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Before each FCP transdaction, the entire 512 bytes of the FCP frame were
cleared, then values filled in.

Clear only the bytes between filled-in bytes and end of the
- request frame, or
- response frame if data from a larger response will be needed, or
- whole frame if data from a variable length response will be taken.

Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
---
drivers/media/dvb/firewire/firedtv-avc.c | 146 ++++++++++-------------
1 file changed, 65 insertions(+), 81 deletions(-)

Index: linux-2.6.32-rc7/drivers/media/dvb/firewire/firedtv-avc.c
===================================================================
--- linux-2.6.32-rc7.orig/drivers/media/dvb/firewire/firedtv-avc.c
+++ linux-2.6.32-rc7/drivers/media/dvb/firewire/firedtv-avc.c
@@ -87,6 +87,21 @@ struct avc_response_frame {
u8 operand[509];
};

+#define LAST_OPERAND (509 - 1)
+
+static inline void clear_operands(struct avc_command_frame *c, int from, int to)
+{
+ memset(&c->operand[from], 0, to - from + 1);
+}
+
+static void pad_operands(struct avc_command_frame *c, int from)
+{
+ int to = ALIGN(from, 4);
+
+ if (from <= to && to <= LAST_OPERAND)
+ clear_operands(c, from, to);
+}
+
#define AVC_DEBUG_READ_DESCRIPTOR 0x0001
#define AVC_DEBUG_DSIT 0x0002
#define AVC_DEBUG_DSD 0x0004
@@ -303,8 +318,8 @@ static int add_pid_filter(struct firedtv
* tuning command for setting the relative LNB frequency
* (not supported by the AVC standard)
*/
-static void avc_tuner_tuneqpsk(struct firedtv *fdtv,
- struct dvb_frontend_parameters *params)
+static int avc_tuner_tuneqpsk(struct firedtv *fdtv,
+ struct dvb_frontend_parameters *params)
{
struct avc_command_frame *c = (void *)fdtv->avc_data;

@@ -356,14 +371,15 @@ static void avc_tuner_tuneqpsk(struct fi
c->operand[13] = 0x1;
c->operand[14] = 0xff;
c->operand[15] = 0xff;
- fdtv->avc_data_length = 20;
+
+ return 16;
} else {
- fdtv->avc_data_length = 16;
+ return 13;
}
}

-static void avc_tuner_dsd_dvb_c(struct firedtv *fdtv,
- struct dvb_frontend_parameters *params)
+static int avc_tuner_dsd_dvb_c(struct firedtv *fdtv,
+ struct dvb_frontend_parameters *params)
{
struct avc_command_frame *c = (void *)fdtv->avc_data;

@@ -427,13 +443,11 @@ static void avc_tuner_dsd_dvb_c(struct f
c->operand[20] = 0x00;
c->operand[21] = 0x00;

- /* Add PIDs to filter */
- fdtv->avc_data_length =
- ALIGN(22 + add_pid_filter(fdtv, &c->operand[22]) + 3, 4);
+ return 22 + add_pid_filter(fdtv, &c->operand[22]);
}

-static void avc_tuner_dsd_dvb_t(struct firedtv *fdtv,
- struct dvb_frontend_parameters *params)
+static int avc_tuner_dsd_dvb_t(struct firedtv *fdtv,
+ struct dvb_frontend_parameters *params)
{
struct dvb_ofdm_parameters *ofdm = &params->u.ofdm;
struct avc_command_frame *c = (void *)fdtv->avc_data;
@@ -531,32 +545,31 @@ static void avc_tuner_dsd_dvb_t(struct f
c->operand[15] = 0x00; /* network_ID[0] */
c->operand[16] = 0x00; /* network_ID[1] */

- /* Add PIDs to filter */
- fdtv->avc_data_length =
- ALIGN(17 + add_pid_filter(fdtv, &c->operand[17]) + 3, 4);
+ return 17 + add_pid_filter(fdtv, &c->operand[17]);
}

int avc_tuner_dsd(struct firedtv *fdtv,
struct dvb_frontend_parameters *params)
{
struct avc_command_frame *c = (void *)fdtv->avc_data;
- int ret;
+ int pos, ret;

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;

switch (fdtv->type) {
case FIREDTV_DVB_S:
- case FIREDTV_DVB_S2: avc_tuner_tuneqpsk(fdtv, params); break;
- case FIREDTV_DVB_C: avc_tuner_dsd_dvb_c(fdtv, params); break;
- case FIREDTV_DVB_T: avc_tuner_dsd_dvb_t(fdtv, params); break;
+ case FIREDTV_DVB_S2: pos = avc_tuner_tuneqpsk(fdtv, params); break;
+ case FIREDTV_DVB_C: pos = avc_tuner_dsd_dvb_c(fdtv, params); break;
+ case FIREDTV_DVB_T: pos = avc_tuner_dsd_dvb_t(fdtv, params); break;
default:
BUG();
}
+ pad_operands(c, pos);
+
+ fdtv->avc_data_length = ALIGN(3 + pos, 4);
ret = avc_write(fdtv);
#if 0
/*
@@ -585,8 +598,6 @@ int avc_tuner_set_pids(struct firedtv *f

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_DSD;
@@ -608,6 +619,7 @@ int avc_tuner_set_pids(struct firedtv *f
c->operand[pos++] = 0x00; /* tableID */
c->operand[pos++] = 0x00; /* filter_length */
}
+ pad_operands(c, pos);

fdtv->avc_data_length = ALIGN(3 + pos, 4);
ret = avc_write(fdtv);
@@ -629,8 +641,6 @@ int avc_tuner_get_ts(struct firedtv *fdt

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_DSIT;
@@ -644,9 +654,12 @@ int avc_tuner_get_ts(struct firedtv *fdt
c->operand[4] = 0x00; /* antenna number */
c->operand[5] = 0x0; /* system_specific_search_flags */
c->operand[6] = sl; /* system_specific_multiplex selection_length */
- c->operand[7] = 0x00; /* valid_flags [0] */
- c->operand[8] = 0x00; /* valid_flags [1] */
- c->operand[7 + sl] = 0x00; /* nr_of_dsit_sel_specs (always 0) */
+ /*
+ * operand[7]: valid_flags[0]
+ * operand[8]: valid_flags[1]
+ * operand[7 + sl]: nr_of_dsit_sel_specs (always 0)
+ */
+ clear_operands(c, 7, 24);

fdtv->avc_data_length = fdtv->type == FIREDTV_DVB_T ? 24 : 28;
ret = avc_write(fdtv);
@@ -669,8 +682,6 @@ int avc_identify_subunit(struct firedtv

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_READ_DESCRIPTOR;
@@ -682,6 +693,7 @@ int avc_identify_subunit(struct firedtv
c->operand[4] = 0x08; /* length lowbyte */
c->operand[5] = 0x00; /* offset highbyte */
c->operand[6] = 0x0d; /* offset lowbyte */
+ clear_operands(c, 7, 8); /* padding */

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -710,19 +722,18 @@ int avc_tuner_status(struct firedtv *fdt

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_READ_DESCRIPTOR;

c->operand[0] = DESCRIPTOR_TUNER_STATUS;
c->operand[1] = 0xff; /* read_result_status */
- c->operand[2] = 0x00; /* reserved */
- c->operand[3] = 0; /* SIZEOF_ANTENNA_INPUT_INFO >> 8; */
- c->operand[4] = 0; /* SIZEOF_ANTENNA_INPUT_INFO & 0xff; */
- c->operand[5] = 0x00;
- c->operand[6] = 0x00;
+ /*
+ * operand[2]: reserved
+ * operand[3]: SIZEOF_ANTENNA_INPUT_INFO >> 8
+ * operand[4]: SIZEOF_ANTENNA_INPUT_INFO & 0xff
+ */
+ clear_operands(c, 2, 31);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -788,12 +799,10 @@ int avc_lnb_control(struct firedtv *fdtv
{
struct avc_command_frame *c = (void *)fdtv->avc_data;
struct avc_response_frame *r = (void *)fdtv->avc_data;
- int i, j, k, ret;
+ int pos, j, k, ret;

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -802,23 +811,21 @@ int avc_lnb_control(struct firedtv *fdtv
c->operand[1] = SFE_VENDOR_DE_COMPANYID_1;
c->operand[2] = SFE_VENDOR_DE_COMPANYID_2;
c->operand[3] = SFE_VENDOR_OPCODE_LNB_CONTROL;
-
c->operand[4] = voltage;
c->operand[5] = nrdiseq;

- i = 6;
-
+ pos = 6;
for (j = 0; j < nrdiseq; j++) {
- c->operand[i++] = diseqcmd[j].msg_len;
+ c->operand[pos++] = diseqcmd[j].msg_len;

for (k = 0; k < diseqcmd[j].msg_len; k++)
- c->operand[i++] = diseqcmd[j].msg[k];
+ c->operand[pos++] = diseqcmd[j].msg[k];
}
+ c->operand[pos++] = burst;
+ c->operand[pos++] = conttone;
+ pad_operands(c, pos);

- c->operand[i++] = burst;
- c->operand[i++] = conttone;
-
- fdtv->avc_data_length = ALIGN(3 + i, 4);
+ fdtv->avc_data_length = ALIGN(3 + pos, 4);
ret = avc_write(fdtv);
if (ret < 0)
goto out;
@@ -840,8 +847,6 @@ int avc_register_remote_control(struct f

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_NOTIFY;
c->subunit = AVC_SUBUNIT_TYPE_UNIT | 7;
c->opcode = AVC_OPCODE_VENDOR;
@@ -850,6 +855,7 @@ int avc_register_remote_control(struct f
c->operand[1] = SFE_VENDOR_DE_COMPANYID_1;
c->operand[2] = SFE_VENDOR_DE_COMPANYID_2;
c->operand[3] = SFE_VENDOR_OPCODE_REGISTER_REMOTE_CONTROL;
+ c->operand[4] = 0; /* padding */

fdtv->avc_data_length = 8;
ret = avc_write(fdtv);
@@ -878,8 +884,6 @@ int avc_tuner_host2ca(struct firedtv *fd

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -890,8 +894,7 @@ int avc_tuner_host2ca(struct firedtv *fd
c->operand[3] = SFE_VENDOR_OPCODE_HOST2CA;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_APPLICATION_INFO; /* ca tag */
- c->operand[6] = 0; /* more/last */
- c->operand[7] = 0; /* length */
+ clear_operands(c, 6, 8);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -937,8 +940,6 @@ int avc_ca_app_info(struct firedtv *fdtv

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_STATUS;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -949,6 +950,7 @@ int avc_ca_app_info(struct firedtv *fdtv
c->operand[3] = SFE_VENDOR_OPCODE_CA2HOST;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_APPLICATION_INFO; /* ca tag */
+ clear_operands(c, 6, LAST_OPERAND);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -979,8 +981,6 @@ int avc_ca_info(struct firedtv *fdtv, ch

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_STATUS;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -991,6 +991,7 @@ int avc_ca_info(struct firedtv *fdtv, ch
c->operand[3] = SFE_VENDOR_OPCODE_CA2HOST;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_APPLICATION_INFO; /* ca tag */
+ clear_operands(c, 6, LAST_OPERAND);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -1020,8 +1021,6 @@ int avc_ca_reset(struct firedtv *fdtv)

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -1064,8 +1063,6 @@ int avc_ca_pmt(struct firedtv *fdtv, cha

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_CONTROL;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -1096,7 +1093,7 @@ int avc_ca_pmt(struct firedtv *fdtv, cha

c->operand[12] = 0x02; /* Table id=2 */
c->operand[13] = 0x80; /* Section syntax + length */
- /* c->operand[14] = XXXprogram_info_length + 12; */
+
c->operand[15] = msg[1]; /* Program number */
c->operand[16] = msg[2];
c->operand[17] = 0x01; /* Version number=0 + current/next=1 */
@@ -1144,12 +1141,7 @@ int avc_ca_pmt(struct firedtv *fdtv, cha
write_pos += es_info_length;
}
}
-
- /* CRC */
- c->operand[write_pos++] = 0x00;
- c->operand[write_pos++] = 0x00;
- c->operand[write_pos++] = 0x00;
- c->operand[write_pos++] = 0x00;
+ write_pos += 4; /* CRC */

c->operand[7] = 0x82;
c->operand[8] = (write_pos - 10) >> 8;
@@ -1161,6 +1153,7 @@ int avc_ca_pmt(struct firedtv *fdtv, cha
c->operand[write_pos - 3] = (crc32_csum >> 16) & 0xff;
c->operand[write_pos - 2] = (crc32_csum >> 8) & 0xff;
c->operand[write_pos - 1] = (crc32_csum >> 0) & 0xff;
+ pad_operands(c, write_pos);

fdtv->avc_data_length = ALIGN(3 + write_pos, 4);
ret = avc_write(fdtv);
@@ -1186,8 +1179,6 @@ int avc_ca_get_time_date(struct firedtv

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_STATUS;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -1198,8 +1189,7 @@ int avc_ca_get_time_date(struct firedtv
c->operand[3] = SFE_VENDOR_OPCODE_CA2HOST;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_DATE_TIME; /* ca tag */
- c->operand[6] = 0; /* more/last */
- c->operand[7] = 0; /* length */
+ clear_operands(c, 6, LAST_OPERAND);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -1222,8 +1212,6 @@ int avc_ca_enter_menu(struct firedtv *fd

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_STATUS;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -1234,8 +1222,7 @@ int avc_ca_enter_menu(struct firedtv *fd
c->operand[3] = SFE_VENDOR_OPCODE_HOST2CA;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_ENTER_MENU;
- c->operand[6] = 0; /* more/last */
- c->operand[7] = 0; /* length */
+ clear_operands(c, 6, 8);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);
@@ -1255,8 +1242,6 @@ int avc_ca_get_mmi(struct firedtv *fdtv,

mutex_lock(&fdtv->avc_mutex);

- memset(c, 0, sizeof(*c));
-
c->ctype = AVC_CTYPE_STATUS;
c->subunit = AVC_SUBUNIT_TYPE_TUNER | fdtv->subunit;
c->opcode = AVC_OPCODE_VENDOR;
@@ -1267,8 +1252,7 @@ int avc_ca_get_mmi(struct firedtv *fdtv,
c->operand[3] = SFE_VENDOR_OPCODE_CA2HOST;
c->operand[4] = 0; /* slot */
c->operand[5] = SFE_VENDOR_TAG_CA_MMI;
- c->operand[6] = 0; /* more/last */
- c->operand[7] = 0; /* length */
+ clear_operands(c, 6, LAST_OPERAND);

fdtv->avc_data_length = 12;
ret = avc_write(fdtv);

--
Stefan Richter
-=====-==--= =-== =--=-
http://arcgraph.de/sr/

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