Re: [PATCH v3 1/1] r8169: Coalesce RTL8411b PHY power-down recovery programming instructions to reduce spinlock stalls
From: Mirsad Todorovac
Date: Sun Oct 29 2023 - 00:57:08 EST
On 10/28/23 21:21, Heiner Kallweit wrote:
On 28.10.2023 13:05, Mirsad Goran Todorovac wrote:
On RTL8411b the RX unit gets confused if the PHY is powered-down.
This was reported in [0] and confirmed by Realtek. Realtek provided
a sequence to fix the RX unit after PHY wakeup.
A series of about 130 r8168_mac_ocp_write() calls is performed to
program the RTL registers for recovery.
r8168_mac_ocp_write() expands to this code:
static void __r8168_mac_ocp_write(struct rtl8169_private *tp, u32 reg, u32 data)
{
if (rtl_ocp_reg_failure(reg))
return;
RTL_W32(tp, OCPDR, OCPAR_FLAG | (reg << 15) | data);
}
static void r8168_mac_ocp_write(struct rtl8169_private *tp, u32 reg, u32 data)
{
unsigned long flags;
raw_spin_lock_irqsave(&tp->mac_ocp_lock, flags);
__r8168_mac_ocp_write(tp, reg, data);
raw_spin_unlock_irqrestore(&tp->mac_ocp_lock, flags);
}
Register programming is done through RTL_W32() macro which expands into
#define RTL_W32(tp, reg, val32) writel((val32), tp->mmio_addr + (reg))
which is further (on Alpha):
extern inline void writel(u32 b, volatile void __iomem *addr)
{
mb();
__raw_writel(b, addr);
}
or on i386/x86_64:
#define build_mmio_write(name, size, type, reg, barrier) \
static inline void name(type val, volatile void __iomem *addr) \
{ asm volatile("mov" size " %0,%1": :reg (val), \
"m" (*(volatile type __force *)addr) barrier); }
build_mmio_write(writel, "l", unsigned int, "r", :"memory")
This obviously involves iat least a compiler barrier.
mb() expands into something like this i.e. on x86_64:
#define mb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
This means a whole lot of memory bus barriers: for spin_lock_irqsave(),
memory barrier, writel(), and spin_unlock_irqrestore().
With about 130 of these sequential calls to r8168_mac_ocp_write() this looks like
a LOCK storm that will thunder all of the cores and CPUs on the same memory controller
for certain time that locked memory read-modify-write cyclo or I/O takes to finish.
In a sequential case of RTL register programming, the writes to RTL registers
can be coalesced under a same raw spinlock. This can dramatically decrease the
number of bus stalls in a multicore or multi-CPU system:
static void __r8168_mac_ocp_write_seq(struct rtl8169_private *tp,
const struct recover_8411b_info *array)
{
struct recover_8411b_info const *p = array;
while (p->reg) {
if (!rtl_ocp_reg_failure(p->reg))
RTL_W32(tp, OCPDR, OCPAR_FLAG | (p->reg << 15) | p->data);
p++;
}
}
static void r8168_mac_ocp_write_seq(struct rtl8169_private *tp,
const struct recover_8411b_info *array)
{
unsigned long flags;
raw_spin_lock_irqsave(&tp->mac_ocp_lock, flags);
__r8168_mac_ocp_write_seq(tp, array);
raw_spin_unlock_irqrestore(&tp->mac_ocp_lock, flags);
}
static void rtl_hw_start_8411_2(struct rtl8169_private *tp)
{
...
/* The following Realtek-provided magic fixes an issue with the RX unit
* getting confused after the PHY having been powered-down.
*/
static const struct recover_8411b_info init_zero_seq[] = {
{ 0xFC28, 0x0000 }, { 0xFC2A, 0x0000 }, { 0xFC2C, 0x0000 }, { 0xFC2E, 0x0000 },
...
};
static const struct recover_8411b_info recover_seq[] = {
{ 0xF800, 0xE008 }, { 0xF802, 0xE00A }, { 0xF804, 0xE00C }, { 0xF806, 0xE00E },
...
};
static const struct recover_8411b_info final_seq[] = {
{ 0xFC2A, 0x0743 }, { 0xFC2C, 0x0801 }, { 0xFC2E, 0x0BE9 }, { 0xFC30, 0x02FD },
...
};
r8168_mac_ocp_write_seq(tp, init_zero_seq);
mdelay(3);
r8168_mac_ocp_write(tp, 0xFC26, 0x0000);
r8168_mac_ocp_write_seq(tp, recover_seq);
r8168_mac_ocp_write(tp, 0xFC26, 0x8000);
r8168_mac_ocp_write_seq(tp, final_seq);
}
The hex data is preserved intact through s/r8168_mac_ocp_write[(]tp,/{ / and s/[)];/ },/
functions that only changed the function names and the ending of the line, so the actual
hex data is unchanged.
Note that the original reason for the introduction of the commit fe4e8db0392a6
was to enable recovery of the RX unit on the RTL8411b which was confused by the
powered-down PHY. This sequence of r8168_mac_ocp_write() calls amplifies the problem
I still have a problem with this statement as you're saying that the original
problem still exists. I don't think that's the case.
I will not disagree about it.
But we have only reduced the number of spin_lock_irqsave/spin_unlock_irqrestore()
pairs.
Maybe additionally, on the low level, memory barrier isn't required for each write to
MMIO?
If it still uses a LOCK addl $0, m32/m64, then it still creates 130 instances of all core
bus locks for this NIC reset after the lost PHY? I'm just thinking, this is nothing
authoritative ...
into a series of about 500+ memory bus locks, most waiting for the main memory read,
modify and write under a LOCK. The memory barrier in RTL_W32 should suffice for
the programming sequence to reach RTL NIC registers.
[0] https://bugzilla.redhat.com/show_bug.cgi?id=1692075
Fixes: fe4e8db0392a6 ("r8169: fix issue with confused RX unit after PHY power-down on RTL8411b")
Cc: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: nic_swsd@xxxxxxxxxxx
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/lkml/20231028005153.2180411-1-mirsad.todorovac@xxxxxxxxxxxx/
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx>
---
v3:
removed register/mask pair array sentinels, so using ARRAY_SIZE().
avoided duplication of RTL_W32() call code as advised by Heiner.
drivers/net/ethernet/realtek/r8169_main.c | 198 ++++++++--------------
1 file changed, 72 insertions(+), 126 deletions(-)
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 361b90007148..3b28bec7098b 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -939,6 +939,32 @@ static void r8168_mac_ocp_modify(struct rtl8169_private *tp, u32 reg, u16 mask,
raw_spin_unlock_irqrestore(&tp->mac_ocp_lock, flags);
}
+struct e_info_regmask_pair {
+ u32 reg;
+ u32 data;
+};
+
+static void __r8168_mac_ocp_write_seq(struct rtl8169_private *tp,
+ const struct e_info_regmask_pair *array, int len)
+{
+ struct e_info_regmask_pair const *p;
+
+ for (p = array; len--; p++)
+ __r8168_mac_ocp_write(tp, p->reg, p->data);
+}
+
+static void _r8168_mac_ocp_write_seq(struct rtl8169_private *tp,
+ const struct e_info_regmask_pair *array, int len)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&tp->mac_ocp_lock, flags);
+ __r8168_mac_ocp_write_seq(tp, array, len);
+ raw_spin_unlock_irqrestore(&tp->mac_ocp_lock, flags);
+}
+
+#define r8168_mac_ocp_write_seq(tp, a) _r8168_mac_ocp_write_seq(tp, a, ARRAY_SIZE(a))
+
/* Work around a hw issue with RTL8168g PHY, the quirk disables
* PHY MCU interrupts before PHY power-down.
*/
@@ -3107,138 +3133,58 @@ static void rtl_hw_start_8411_2(struct rtl8169_private *tp)
/* The following Realtek-provided magic fixes an issue with the RX unit
* getting confused after the PHY having been powered-down.
*/
- r8168_mac_ocp_write(tp, 0xFC28, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC2A, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC2C, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC2E, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC30, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC32, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC34, 0x0000);
- r8168_mac_ocp_write(tp, 0xFC36, 0x0000);
+
+ static const struct e_info_regmask_pair init_zero_seq[] = {
+ { 0xFC28, 0x0000 }, { 0xFC2A, 0x0000 }, { 0xFC2C, 0x0000 }, { 0xFC2E, 0x0000 },
+ { 0xFC30, 0x0000 }, { 0xFC32, 0x0000 }, { 0xFC34, 0x0000 }, { 0xFC36, 0x0000 },
+ };
+
Don't mix code and variable declarations. Did you run checkpatch?
I think it would complain here.
Thank you for the warning, I will fix it.
As I said to Mr. Greg, I will do the required number of iterations to fix this issue.
I will add checkpatch to my routine handling of my submitted patches.
Thanks,
Mirsad
+ static const struct e_info_regmask_pair recover_seq[] = {
+ { 0xF800, 0xE008 }, { 0xF802, 0xE00A }, { 0xF804, 0xE00C }, { 0xF806, 0xE00E },
+ { 0xF808, 0xE027 }, { 0xF80A, 0xE04F }, { 0xF80C, 0xE05E }, { 0xF80E, 0xE065 },
+ { 0xF810, 0xC602 }, { 0xF812, 0xBE00 }, { 0xF814, 0x0000 }, { 0xF816, 0xC502 },
+ { 0xF818, 0xBD00 }, { 0xF81A, 0x074C }, { 0xF81C, 0xC302 }, { 0xF81E, 0xBB00 },
+ { 0xF820, 0x080A }, { 0xF822, 0x6420 }, { 0xF824, 0x48C2 }, { 0xF826, 0x8C20 },
+ { 0xF828, 0xC516 }, { 0xF82A, 0x64A4 }, { 0xF82C, 0x49C0 }, { 0xF82E, 0xF009 },
+ { 0xF830, 0x74A2 }, { 0xF832, 0x8CA5 }, { 0xF834, 0x74A0 }, { 0xF836, 0xC50E },
+ { 0xF838, 0x9CA2 }, { 0xF83A, 0x1C11 }, { 0xF83C, 0x9CA0 }, { 0xF83E, 0xE006 },
+ { 0xF840, 0x74F8 }, { 0xF842, 0x48C4 }, { 0xF844, 0x8CF8 }, { 0xF846, 0xC404 },
+ { 0xF848, 0xBC00 }, { 0xF84A, 0xC403 }, { 0xF84C, 0xBC00 }, { 0xF84E, 0x0BF2 },
+ { 0xF850, 0x0C0A }, { 0xF852, 0xE434 }, { 0xF854, 0xD3C0 }, { 0xF856, 0x49D9 },
+ { 0xF858, 0xF01F }, { 0xF85A, 0xC526 }, { 0xF85C, 0x64A5 }, { 0xF85E, 0x1400 },
+ { 0xF860, 0xF007 }, { 0xF862, 0x0C01 }, { 0xF864, 0x8CA5 }, { 0xF866, 0x1C15 },
+ { 0xF868, 0xC51B }, { 0xF86A, 0x9CA0 }, { 0xF86C, 0xE013 }, { 0xF86E, 0xC519 },
+ { 0xF870, 0x74A0 }, { 0xF872, 0x48C4 }, { 0xF874, 0x8CA0 }, { 0xF876, 0xC516 },
+ { 0xF878, 0x74A4 }, { 0xF87A, 0x48C8 }, { 0xF87C, 0x48CA }, { 0xF87E, 0x9CA4 },
+ { 0xF880, 0xC512 }, { 0xF882, 0x1B00 }, { 0xF884, 0x9BA0 }, { 0xF886, 0x1B1C },
+ { 0xF888, 0x483F }, { 0xF88A, 0x9BA2 }, { 0xF88C, 0x1B04 }, { 0xF88E, 0xC508 },
+ { 0xF890, 0x9BA0 }, { 0xF892, 0xC505 }, { 0xF894, 0xBD00 }, { 0xF896, 0xC502 },
+ { 0xF898, 0xBD00 }, { 0xF89A, 0x0300 }, { 0xF89C, 0x051E }, { 0xF89E, 0xE434 },
+ { 0xF8A0, 0xE018 }, { 0xF8A2, 0xE092 }, { 0xF8A4, 0xDE20 }, { 0xF8A6, 0xD3C0 },
+ { 0xF8A8, 0xC50F }, { 0xF8AA, 0x76A4 }, { 0xF8AC, 0x49E3 }, { 0xF8AE, 0xF007 },
+ { 0xF8B0, 0x49C0 }, { 0xF8B2, 0xF103 }, { 0xF8B4, 0xC607 }, { 0xF8B6, 0xBE00 },
+ { 0xF8B8, 0xC606 }, { 0xF8BA, 0xBE00 }, { 0xF8BC, 0xC602 }, { 0xF8BE, 0xBE00 },
+ { 0xF8C0, 0x0C4C }, { 0xF8C2, 0x0C28 }, { 0xF8C4, 0x0C2C }, { 0xF8C6, 0xDC00 },
+ { 0xF8C8, 0xC707 }, { 0xF8CA, 0x1D00 }, { 0xF8CC, 0x8DE2 }, { 0xF8CE, 0x48C1 },
+ { 0xF8D0, 0xC502 }, { 0xF8D2, 0xBD00 }, { 0xF8D4, 0x00AA }, { 0xF8D6, 0xE0C0 },
+ { 0xF8D8, 0xC502 }, { 0xF8DA, 0xBD00 }, { 0xF8DC, 0x0132 },
+ };
+
+ static const struct e_info_regmask_pair final_seq[] = {
+ { 0xFC2A, 0x0743 }, { 0xFC2C, 0x0801 }, { 0xFC2E, 0x0BE9 }, { 0xFC30, 0x02FD },
+ { 0xFC32, 0x0C25 }, { 0xFC34, 0x00A9 }, { 0xFC36, 0x012D },
+ };
+
+ r8168_mac_ocp_write_seq(tp, init_zero_seq);
mdelay(3);
r8168_mac_ocp_write(tp, 0xFC26, 0x0000);
- r8168_mac_ocp_write(tp, 0xF800, 0xE008);
- r8168_mac_ocp_write(tp, 0xF802, 0xE00A);
- r8168_mac_ocp_write(tp, 0xF804, 0xE00C);
- r8168_mac_ocp_write(tp, 0xF806, 0xE00E);
- r8168_mac_ocp_write(tp, 0xF808, 0xE027);
- r8168_mac_ocp_write(tp, 0xF80A, 0xE04F);
- r8168_mac_ocp_write(tp, 0xF80C, 0xE05E);
- r8168_mac_ocp_write(tp, 0xF80E, 0xE065);
- r8168_mac_ocp_write(tp, 0xF810, 0xC602);
- r8168_mac_ocp_write(tp, 0xF812, 0xBE00);
- r8168_mac_ocp_write(tp, 0xF814, 0x0000);
- r8168_mac_ocp_write(tp, 0xF816, 0xC502);
- r8168_mac_ocp_write(tp, 0xF818, 0xBD00);
- r8168_mac_ocp_write(tp, 0xF81A, 0x074C);
- r8168_mac_ocp_write(tp, 0xF81C, 0xC302);
- r8168_mac_ocp_write(tp, 0xF81E, 0xBB00);
- r8168_mac_ocp_write(tp, 0xF820, 0x080A);
- r8168_mac_ocp_write(tp, 0xF822, 0x6420);
- r8168_mac_ocp_write(tp, 0xF824, 0x48C2);
- r8168_mac_ocp_write(tp, 0xF826, 0x8C20);
- r8168_mac_ocp_write(tp, 0xF828, 0xC516);
- r8168_mac_ocp_write(tp, 0xF82A, 0x64A4);
- r8168_mac_ocp_write(tp, 0xF82C, 0x49C0);
- r8168_mac_ocp_write(tp, 0xF82E, 0xF009);
- r8168_mac_ocp_write(tp, 0xF830, 0x74A2);
- r8168_mac_ocp_write(tp, 0xF832, 0x8CA5);
- r8168_mac_ocp_write(tp, 0xF834, 0x74A0);
- r8168_mac_ocp_write(tp, 0xF836, 0xC50E);
- r8168_mac_ocp_write(tp, 0xF838, 0x9CA2);
- r8168_mac_ocp_write(tp, 0xF83A, 0x1C11);
- r8168_mac_ocp_write(tp, 0xF83C, 0x9CA0);
- r8168_mac_ocp_write(tp, 0xF83E, 0xE006);
- r8168_mac_ocp_write(tp, 0xF840, 0x74F8);
- r8168_mac_ocp_write(tp, 0xF842, 0x48C4);
- r8168_mac_ocp_write(tp, 0xF844, 0x8CF8);
- r8168_mac_ocp_write(tp, 0xF846, 0xC404);
- r8168_mac_ocp_write(tp, 0xF848, 0xBC00);
- r8168_mac_ocp_write(tp, 0xF84A, 0xC403);
- r8168_mac_ocp_write(tp, 0xF84C, 0xBC00);
- r8168_mac_ocp_write(tp, 0xF84E, 0x0BF2);
- r8168_mac_ocp_write(tp, 0xF850, 0x0C0A);
- r8168_mac_ocp_write(tp, 0xF852, 0xE434);
- r8168_mac_ocp_write(tp, 0xF854, 0xD3C0);
- r8168_mac_ocp_write(tp, 0xF856, 0x49D9);
- r8168_mac_ocp_write(tp, 0xF858, 0xF01F);
- r8168_mac_ocp_write(tp, 0xF85A, 0xC526);
- r8168_mac_ocp_write(tp, 0xF85C, 0x64A5);
- r8168_mac_ocp_write(tp, 0xF85E, 0x1400);
- r8168_mac_ocp_write(tp, 0xF860, 0xF007);
- r8168_mac_ocp_write(tp, 0xF862, 0x0C01);
- r8168_mac_ocp_write(tp, 0xF864, 0x8CA5);
- r8168_mac_ocp_write(tp, 0xF866, 0x1C15);
- r8168_mac_ocp_write(tp, 0xF868, 0xC51B);
- r8168_mac_ocp_write(tp, 0xF86A, 0x9CA0);
- r8168_mac_ocp_write(tp, 0xF86C, 0xE013);
- r8168_mac_ocp_write(tp, 0xF86E, 0xC519);
- r8168_mac_ocp_write(tp, 0xF870, 0x74A0);
- r8168_mac_ocp_write(tp, 0xF872, 0x48C4);
- r8168_mac_ocp_write(tp, 0xF874, 0x8CA0);
- r8168_mac_ocp_write(tp, 0xF876, 0xC516);
- r8168_mac_ocp_write(tp, 0xF878, 0x74A4);
- r8168_mac_ocp_write(tp, 0xF87A, 0x48C8);
- r8168_mac_ocp_write(tp, 0xF87C, 0x48CA);
- r8168_mac_ocp_write(tp, 0xF87E, 0x9CA4);
- r8168_mac_ocp_write(tp, 0xF880, 0xC512);
- r8168_mac_ocp_write(tp, 0xF882, 0x1B00);
- r8168_mac_ocp_write(tp, 0xF884, 0x9BA0);
- r8168_mac_ocp_write(tp, 0xF886, 0x1B1C);
- r8168_mac_ocp_write(tp, 0xF888, 0x483F);
- r8168_mac_ocp_write(tp, 0xF88A, 0x9BA2);
- r8168_mac_ocp_write(tp, 0xF88C, 0x1B04);
- r8168_mac_ocp_write(tp, 0xF88E, 0xC508);
- r8168_mac_ocp_write(tp, 0xF890, 0x9BA0);
- r8168_mac_ocp_write(tp, 0xF892, 0xC505);
- r8168_mac_ocp_write(tp, 0xF894, 0xBD00);
- r8168_mac_ocp_write(tp, 0xF896, 0xC502);
- r8168_mac_ocp_write(tp, 0xF898, 0xBD00);
- r8168_mac_ocp_write(tp, 0xF89A, 0x0300);
- r8168_mac_ocp_write(tp, 0xF89C, 0x051E);
- r8168_mac_ocp_write(tp, 0xF89E, 0xE434);
- r8168_mac_ocp_write(tp, 0xF8A0, 0xE018);
- r8168_mac_ocp_write(tp, 0xF8A2, 0xE092);
- r8168_mac_ocp_write(tp, 0xF8A4, 0xDE20);
- r8168_mac_ocp_write(tp, 0xF8A6, 0xD3C0);
- r8168_mac_ocp_write(tp, 0xF8A8, 0xC50F);
- r8168_mac_ocp_write(tp, 0xF8AA, 0x76A4);
- r8168_mac_ocp_write(tp, 0xF8AC, 0x49E3);
- r8168_mac_ocp_write(tp, 0xF8AE, 0xF007);
- r8168_mac_ocp_write(tp, 0xF8B0, 0x49C0);
- r8168_mac_ocp_write(tp, 0xF8B2, 0xF103);
- r8168_mac_ocp_write(tp, 0xF8B4, 0xC607);
- r8168_mac_ocp_write(tp, 0xF8B6, 0xBE00);
- r8168_mac_ocp_write(tp, 0xF8B8, 0xC606);
- r8168_mac_ocp_write(tp, 0xF8BA, 0xBE00);
- r8168_mac_ocp_write(tp, 0xF8BC, 0xC602);
- r8168_mac_ocp_write(tp, 0xF8BE, 0xBE00);
- r8168_mac_ocp_write(tp, 0xF8C0, 0x0C4C);
- r8168_mac_ocp_write(tp, 0xF8C2, 0x0C28);
- r8168_mac_ocp_write(tp, 0xF8C4, 0x0C2C);
- r8168_mac_ocp_write(tp, 0xF8C6, 0xDC00);
- r8168_mac_ocp_write(tp, 0xF8C8, 0xC707);
- r8168_mac_ocp_write(tp, 0xF8CA, 0x1D00);
- r8168_mac_ocp_write(tp, 0xF8CC, 0x8DE2);
- r8168_mac_ocp_write(tp, 0xF8CE, 0x48C1);
- r8168_mac_ocp_write(tp, 0xF8D0, 0xC502);
- r8168_mac_ocp_write(tp, 0xF8D2, 0xBD00);
- r8168_mac_ocp_write(tp, 0xF8D4, 0x00AA);
- r8168_mac_ocp_write(tp, 0xF8D6, 0xE0C0);
- r8168_mac_ocp_write(tp, 0xF8D8, 0xC502);
- r8168_mac_ocp_write(tp, 0xF8DA, 0xBD00);
- r8168_mac_ocp_write(tp, 0xF8DC, 0x0132);
+ r8168_mac_ocp_write_seq(tp, recover_seq);
r8168_mac_ocp_write(tp, 0xFC26, 0x8000);
- r8168_mac_ocp_write(tp, 0xFC2A, 0x0743);
- r8168_mac_ocp_write(tp, 0xFC2C, 0x0801);
- r8168_mac_ocp_write(tp, 0xFC2E, 0x0BE9);
- r8168_mac_ocp_write(tp, 0xFC30, 0x02FD);
- r8168_mac_ocp_write(tp, 0xFC32, 0x0C25);
- r8168_mac_ocp_write(tp, 0xFC34, 0x00A9);
- r8168_mac_ocp_write(tp, 0xFC36, 0x012D);
+ r8168_mac_ocp_write_seq(tp, final_seq);
+
}
static void rtl_hw_start_8168h_1(struct rtl8169_private *tp)