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Commit 89993890 authored by Ivo van Doorn's avatar Ivo van Doorn Committed by John W. Linville
Browse files

rt2x00: Fix rt2400pci signal 



After sampling hundreds of RX frame descriptors,
the results were conclusive:
- The Ralink documentation regarding the SIGNAL and RSSI are wrong.

It turns out that of the 5 BBR registers, we should not use BBR0 and BBR1
for SIGNAL and RSSI respectively, but actually BBR1 and BBR2.
BBR0 does show values, but the exact meaning remains unclear,
but they cannot be translated into a SIGNAL or RSSI field.
BBR3, BBR4 and BBR5 are always 0, so their meaning is unknown.

As it turns out, the reported SIGNAL is the PLCP value, this
in contradiction to what was expected looking at rt2500pci which
only reported the PLCP values for OFDM rates and bitrate values
for CCK rates.

This means we should let the driver raise the flag about the contents
of the SIGNAL field so rt2x00lib can always do the right thing based
on what the driver reports.

Signed-off-by: default avatarIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent dac37d72

drivers/net/wireless/rt2x00/rt2400pci.c

+5 −1
Original line number Diff line number Diff line
@@ -1058,9 +1058,11 @@ static void rt2400pci_fill_rxdone(struct queue_entry *entry, 
	struct queue_entry_priv_pci_rx *priv_rx = entry->priv_data;

	u32 word0;

	u32 word2;

	u32 word3;



	rt2x00_desc_read(priv_rx->desc, 0, &word0);

	rt2x00_desc_read(priv_rx->desc, 2, &word2);

	rt2x00_desc_read(priv_rx->desc, 3, &word3);



	rxdesc->flags = 0;

	if (rt2x00_get_field32(word0, RXD_W0_CRC_ERROR))
@@ -1070,9 +1072,11 @@ static void rt2400pci_fill_rxdone(struct queue_entry *entry, 


	/*

	 * Obtain the status about this packet.

	 * The signal is the PLCP value.

	 */

	rxdesc->signal = rt2x00_get_field32(word2, RXD_W2_SIGNAL);

	rxdesc->rssi = rt2x00_get_field32(word2, RXD_W2_RSSI) -

	rxdesc->signal_plcp = 1;

	rxdesc->rssi = rt2x00_get_field32(word2, RXD_W3_RSSI) -

	    entry->queue->rt2x00dev->rssi_offset;

	rxdesc->ofdm = 0;

	rxdesc->size = rt2x00_get_field32(word0, RXD_W0_DATABYTE_COUNT);

drivers/net/wireless/rt2x00/rt2400pci.h

+3 −3
Original line number Diff line number Diff line
@@ -899,13 +899,13 @@ 
 * Word2

 */

#define RXD_W2_BUFFER_LENGTH		FIELD32(0x0000ffff)

#define RXD_W2_SIGNAL			FIELD32(0x00ff0000)

#define RXD_W2_RSSI			FIELD32(0xff000000)

#define RXD_W2_BBR0			FIELD32(0x00ff0000)

#define RXD_W2_SIGNAL			FIELD32(0xff000000)



/*

 * Word3

 */

#define RXD_W3_BBR2			FIELD32(0x000000ff)

#define RXD_W3_RSSI			FIELD32(0x000000ff)

#define RXD_W3_BBR3			FIELD32(0x0000ff00)

#define RXD_W3_BBR4			FIELD32(0x00ff0000)

#define RXD_W3_BBR5			FIELD32(0xff000000)

drivers/net/wireless/rt2x00/rt2500pci.c

+8 −1
Original line number Diff line number Diff line
@@ -1219,10 +1219,17 @@ static void rt2500pci_fill_rxdone(struct queue_entry *entry, 
	if (rt2x00_get_field32(word0, RXD_W0_PHYSICAL_ERROR))

		rxdesc->flags |= RX_FLAG_FAILED_PLCP_CRC;



	/*

	 * Obtain the status about this packet.

	 * When frame was received with an OFDM bitrate,

	 * the signal is the PLCP value. If it was received with

	 * a CCK bitrate the signal is the rate in 100kbit/s.

	 */

	rxdesc->ofdm = rt2x00_get_field32(word0, RXD_W0_OFDM);

	rxdesc->signal = rt2x00_get_field32(word2, RXD_W2_SIGNAL);

	rxdesc->signal_plcp = rxdesc->ofdm;

	rxdesc->rssi = rt2x00_get_field32(word2, RXD_W2_RSSI) -

	    entry->queue->rt2x00dev->rssi_offset;

	rxdesc->ofdm = rt2x00_get_field32(word0, RXD_W0_OFDM);

	rxdesc->size = rt2x00_get_field32(word0, RXD_W0_DATABYTE_COUNT);

	rxdesc->my_bss = !!rt2x00_get_field32(word0, RXD_W0_MY_BSS);

}

drivers/net/wireless/rt2x00/rt2500usb.c

+5 −1
Original line number Diff line number Diff line
@@ -1135,11 +1135,15 @@ static void rt2500usb_fill_rxdone(struct queue_entry *entry, 


	/*

	 * Obtain the status about this packet.

	 * When frame was received with an OFDM bitrate,

	 * the signal is the PLCP value. If it was received with

	 * a CCK bitrate the signal is the rate in 100kbit/s.

	 */

	rxdesc->ofdm = rt2x00_get_field32(word0, RXD_W0_OFDM);

	rxdesc->signal = rt2x00_get_field32(word1, RXD_W1_SIGNAL);

	rxdesc->signal_plcp = rxdesc->ofdm;

	rxdesc->rssi = rt2x00_get_field32(word1, RXD_W1_RSSI) -

	    entry->queue->rt2x00dev->rssi_offset;

	rxdesc->ofdm = rt2x00_get_field32(word0, RXD_W0_OFDM);

	rxdesc->size = rt2x00_get_field32(word0, RXD_W0_DATABYTE_COUNT);

	rxdesc->my_bss = !!rt2x00_get_field32(word0, RXD_W0_MY_BSS);

drivers/net/wireless/rt2x00/rt2x00dev.c

+9 −7
Original line number Diff line number Diff line
@@ -573,6 +573,13 @@ void rt2x00lib_rxdone(struct queue_entry *entry, 
	int idx = -1;

	u16 fc;



	/*

	 * If the signal is the plcp value,

	 * we need to strip the preamble bit (0x08).

	 */

	if (rxdesc->signal_plcp)

		rxdesc->signal &= ~0x08;



	/*

	 * Update RX statistics.

	 */
@@ -580,13 +587,8 @@ void rt2x00lib_rxdone(struct queue_entry *entry, 
	for (i = 0; i < sband->n_bitrates; i++) {

		rate = rt2x00_get_rate(sband->bitrates[i].hw_value);



		/*

		 * When frame was received with an OFDM bitrate,

		 * the signal is the PLCP value. If it was received with

		 * a CCK bitrate the signal is the rate in 100kbit/s.

		 */

		if ((rxdesc->ofdm && rate->plcp == rxdesc->signal) ||

		    (!rxdesc->ofdm && rate->bitrate == rxdesc->signal)) {

		if ((rxdesc->signal_plcp && rate->plcp == rxdesc->signal) ||

		    (!rxdesc->signal_plcp && rate->bitrate == rxdesc->signal)) {

			idx = i;

			break;

		}