V4L/DVB: firedtv: reduce memset()s

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@s5r6.in-berlin.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 65 insertions, 81 deletions

diff --git a/drivers/media/dvb/firewire/firedtv-avc.c b/drivers/media/dvb/firewire/firedtv-avc.c
index e70642811217..1b31bebc27d6 100644
--- a/drivers/media/dvb/firewire/firedtv-avc.c
+++ b/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 *fdtv, u8 *operand)
  * 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 firedtv *fdtv,
                 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 firedtv *fdtv,
         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 firedtv *fdtv,
         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 *fdtv, unsigned char pidc, u16 pid[])
 
         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 *fdtv, unsigned char pidc, u16 pid[])
                         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 *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_DSIT;
@@ -644,9 +654,12 @@ int avc_tuner_get_ts(struct firedtv *fdtv)
         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 *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_READ_DESCRIPTOR;
@@ -682,6 +693,7 @@ int avc_identify_subunit(struct firedtv *fdtv)
         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 *fdtv, struct firedtv_tuner_status *stat)
 
         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, char voltage, char burst,
 {
         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, char voltage, char burst,
         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 firedtv *fdtv)
 
         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 firedtv *fdtv)
         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 *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;
@@ -890,8 +894,7 @@ int avc_tuner_host2ca(struct firedtv *fdtv)
         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, char *app_info, unsigned int *len)
 
         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, char *app_info, unsigned int *len)
         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, char *app_info, unsigned int *len)
 
         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, char *app_info, unsigned int *len)
         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, char *msg, int length)
 
         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, char *msg, int length)
 
         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, char *msg, int length)
                         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, char *msg, int length)
         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 *fdtv, int *interval)
 
         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 *fdtv, int *interval)
         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 *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;
@@ -1234,8 +1222,7 @@ int avc_ca_enter_menu(struct firedtv *fdtv)
         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, char *mmi_object, unsigned int *len)
 
         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, char *mmi_object, unsigned int *len)
         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);