ath9k: add comments for ath9k_hw_configpcipowersave()
This is used for ASPM.
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/hw.c b/drivers/net/wireless/ath9k/hw.c
index 72ca1c8..cfcaaf8 100644
--- a/drivers/net/wireless/ath9k/hw.c
+++ b/drivers/net/wireless/ath9k/hw.c
@@ -2632,6 +2632,15 @@
return status;
}
+/*
+ * Helper for ASPM support.
+ *
+ * Disable PLL when in L0s as well as receiver clock when in L1.
+ * This power saving option must be enabled through the SerDes.
+ *
+ * Programming the SerDes must go through the same 288 bit serial shift
+ * register as the other analog registers. Hence the 9 writes.
+ */
void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore)
{
u8 i;
@@ -2639,13 +2648,20 @@
if (ah->is_pciexpress != true)
return;
+ /* Do not touch SerDes registers */
if (ah->config.pcie_powersave_enable == 2)
return;
+ /* Nothing to do on restore for 11N */
if (restore)
return;
if (AR_SREV_9280_20_OR_LATER(ah)) {
+ /*
+ * AR9280 2.0 or later chips use SerDes values from the
+ * initvals.h initialized depending on chipset during
+ * ath9k_hw_do_attach()
+ */
for (i = 0; i < ah->iniPcieSerdes.ia_rows; i++) {
REG_WRITE(ah, INI_RA(&ah->iniPcieSerdes, i, 0),
INI_RA(&ah->iniPcieSerdes, i, 1));
@@ -2656,10 +2672,12 @@
REG_WRITE(ah, AR_PCIE_SERDES, 0x9248fd00);
REG_WRITE(ah, AR_PCIE_SERDES, 0x24924924);
+ /* RX shut off when elecidle is asserted */
REG_WRITE(ah, AR_PCIE_SERDES, 0xa8000019);
REG_WRITE(ah, AR_PCIE_SERDES, 0x13160820);
REG_WRITE(ah, AR_PCIE_SERDES, 0xe5980560);
+ /* Shut off CLKREQ active in L1 */
if (ah->config.pcie_clock_req)
REG_WRITE(ah, AR_PCIE_SERDES, 0x401deffc);
else
@@ -2669,29 +2687,46 @@
REG_WRITE(ah, AR_PCIE_SERDES, 0xbe105554);
REG_WRITE(ah, AR_PCIE_SERDES, 0x00043007);
+ /* Load the new settings */
REG_WRITE(ah, AR_PCIE_SERDES2, 0x00000000);
udelay(1000);
} else {
REG_WRITE(ah, AR_PCIE_SERDES, 0x9248fc00);
REG_WRITE(ah, AR_PCIE_SERDES, 0x24924924);
+
+ /* RX shut off when elecidle is asserted */
REG_WRITE(ah, AR_PCIE_SERDES, 0x28000039);
REG_WRITE(ah, AR_PCIE_SERDES, 0x53160824);
REG_WRITE(ah, AR_PCIE_SERDES, 0xe5980579);
+
+ /*
+ * Ignore ah->ah_config.pcie_clock_req setting for
+ * pre-AR9280 11n
+ */
REG_WRITE(ah, AR_PCIE_SERDES, 0x001defff);
+
REG_WRITE(ah, AR_PCIE_SERDES, 0x1aaabe40);
REG_WRITE(ah, AR_PCIE_SERDES, 0xbe105554);
REG_WRITE(ah, AR_PCIE_SERDES, 0x000e3007);
+
+ /* Load the new settings */
REG_WRITE(ah, AR_PCIE_SERDES2, 0x00000000);
}
+ /* set bit 19 to allow forcing of pcie core into L1 state */
REG_SET_BIT(ah, AR_PCIE_PM_CTRL, AR_PCIE_PM_CTRL_ENA);
+ /* Several PCIe massages to ensure proper behaviour */
if (ah->config.pcie_waen) {
REG_WRITE(ah, AR_WA, ah->config.pcie_waen);
} else {
if (AR_SREV_9285(ah))
REG_WRITE(ah, AR_WA, AR9285_WA_DEFAULT);
+ /*
+ * On AR9280 chips bit 22 of 0x4004 needs to be set to
+ * otherwise card may disappear.
+ */
else if (AR_SREV_9280(ah))
REG_WRITE(ah, AR_WA, AR9280_WA_DEFAULT);
else