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Date: Wed, 27 Jul 2016 14:09:13 +0000
From: "Avargil, Raanan" <raanan.avargil@...el.com>
To: Jarod Wilson <jarod@...hat.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"Hall, Christopher S" <christopher.s.hall@...el.com>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>
Subject: RE: [Intel-wired-lan] [PATCH net-next v3 1/2] e1000e: factor out
systim sanitization
This is prepatory work for an expanding list of adapter families that have occasional ~10 hour clock jumps when being used for PTP. Factor out the sanitization function and convert to using a feature (bug) flag, per suggestion from Jesse Brandeburg.
Littering functional code with device-specific checks is much messier than simply checking a flag, and having device-specific init set flags as needed.
There are probably a number of other cases in the e1000e code that could/should be converted similarly.
Suggested-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
CC: Jesse Brandeburg <jesse.brandeburg@...el.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
CC: intel-wired-lan@...ts.osuosl.org
CC: netdev@...r.kernel.org
Signed-off-by: Jarod Wilson <jarod@...hat.com>
---
drivers/net/ethernet/intel/e1000e/82571.c | 6 ++- drivers/net/ethernet/intel/e1000e/e1000.h | 1 + drivers/net/ethernet/intel/e1000e/netdev.c | 66 ++++++++++++++++++------------
3 files changed, 44 insertions(+), 29 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/82571.c b/drivers/net/ethernet/intel/e1000e/82571.c
index 7fd4d54..6b03c85 100644
--- a/drivers/net/ethernet/intel/e1000e/82571.c
+++ b/drivers/net/ethernet/intel/e1000e/82571.c
@@ -2032,7 +2032,8 @@ const struct e1000_info e1000_82574_info = {
| FLAG2_DISABLE_ASPM_L0S
| FLAG2_DISABLE_ASPM_L1
| FLAG2_NO_DISABLE_RX
- | FLAG2_DMA_BURST,
+ | FLAG2_DMA_BURST
+ | FLAG2_CHECK_SYSTIM_OVERFLOW,
.pba = 32,
.max_hw_frame_size = DEFAULT_JUMBO,
.get_variants = e1000_get_variants_82571,
@@ -2053,7 +2054,8 @@ const struct e1000_info e1000_82583_info = {
| FLAG_HAS_CTRLEXT_ON_LOAD,
.flags2 = FLAG2_DISABLE_ASPM_L0S
| FLAG2_DISABLE_ASPM_L1
- | FLAG2_NO_DISABLE_RX,
+ | FLAG2_NO_DISABLE_RX
+ | FLAG2_CHECK_SYSTIM_OVERFLOW,
.pba = 32,
.max_hw_frame_size = DEFAULT_JUMBO,
.get_variants = e1000_get_variants_82571,
diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index ef96cd1..879cca4 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -452,6 +452,7 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca);
#define FLAG2_PCIM2PCI_ARBITER_WA BIT(11)
#define FLAG2_DFLT_CRC_STRIPPING BIT(12)
#define FLAG2_CHECK_RX_HWTSTAMP BIT(13)
+#define FLAG2_CHECK_SYSTIM_OVERFLOW BIT(14)
#define E1000_RX_DESC_PS(R, i) \
(&(((union e1000_rx_desc_packet_split *)((R).desc))[i])) diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 41f32c0..1b2df11 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -4303,6 +4303,42 @@ void e1000e_reinit_locked(struct e1000_adapter *adapter) }
/**
+ * e1000e_sanitize_systim - sanitize raw cycle counter reads
+ * @hw: pointer to the HW structure
+ * @systim: cycle_t value read, sanitized and returned
+ *
+ * Errata for 82574/82583 possible bad bits read from SYSTIMH/L:
+ * check to see that the time is incrementing at a reasonable
+ * rate and is a multiple of incvalue.
+ **/
+static cycle_t e1000e_sanitize_systim(struct e1000_hw *hw, cycle_t
+systim) {
+ u64 time_delta, rem, temp;
+ cycle_t systim_next;
+ u32 incvalue;
+ int i;
+
+ incvalue = er32(TIMINCA) & E1000_TIMINCA_INCVALUE_MASK;
+ for (i = 0; i < E1000_MAX_82574_SYSTIM_REREADS; i++) {
+ /* latch SYSTIMH on read of SYSTIML */
+ systim_next = (cycle_t)er32(SYSTIML);
+ systim_next |= (cycle_t)er32(SYSTIMH) << 32;
+
+ time_delta = systim_next - systim;
+ temp = time_delta;
+ /* VMWare users have seen incvalue of zero, don't div / 0 */
+ rem = incvalue ? do_div(temp, incvalue) : (time_delta != 0);
+
+ systim = systim_next;
+
+ if ((time_delta < E1000_82574_SYSTIM_EPSILON) && (rem == 0))
+ break;
+ }
+
+ return systim;
+}
+
+/**
* e1000e_cyclecounter_read - read raw cycle counter (used by time counter)
* @cc: cyclecounter structure
**/
@@ -4312,7 +4348,7 @@ static cycle_t e1000e_cyclecounter_read(const struct cyclecounter *cc)
cc);
struct e1000_hw *hw = &adapter->hw;
u32 systimel, systimeh;
- cycle_t systim, systim_next;
+ cycle_t systim;
/* SYSTIMH latching upon SYSTIML read does not work well.
* This means that if SYSTIML overflows after we read it but before
* we read SYSTIMH, the value of SYSTIMH has been incremented and we @@ -4335,33 +4371,9 @@ static cycle_t e1000e_cyclecounter_read(const struct cyclecounter *cc)
systim = (cycle_t)systimel;
systim |= (cycle_t)systimeh << 32;
- if ((hw->mac.type == e1000_82574) || (hw->mac.type == e1000_82583)) {
- u64 time_delta, rem, temp;
- u32 incvalue;
- int i;
-
- /* errata for 82574/82583 possible bad bits read from SYSTIMH/L
- * check to see that the time is incrementing at a reasonable
- * rate and is a multiple of incvalue
- */
- incvalue = er32(TIMINCA) & E1000_TIMINCA_INCVALUE_MASK;
- for (i = 0; i < E1000_MAX_82574_SYSTIM_REREADS; i++) {
- /* latch SYSTIMH on read of SYSTIML */
- systim_next = (cycle_t)er32(SYSTIML);
- systim_next |= (cycle_t)er32(SYSTIMH) << 32;
-
- time_delta = systim_next - systim;
- temp = time_delta;
- /* VMWare users have seen incvalue of zero, don't div / 0 */
- rem = incvalue ? do_div(temp, incvalue) : (time_delta != 0);
-
- systim = systim_next;
+ if (adapter->flags2 & FLAG2_CHECK_SYSTIM_OVERFLOW)
+ systim = e1000e_sanitize_systim(hw, systim);
- if ((time_delta < E1000_82574_SYSTIM_EPSILON) &&
- (rem == 0))
- break;
- }
- }
return systim;
}
--
1.8.3.1
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Looks ok to me.
Adding Chris who asked what happens if we reach the max retry counter (E1000_MAX_82574_SYSTIM_REREAD)?
This counter is set to 50.
Can you, for testing purposes, decreased this value (or even set it to 0) and see what happens?
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