diff mbox series

[v5,1/8] clk: sunxi-ng: Mark msgbox clocks as critical

Message ID 20191215042455.51001-2-samuel@sholland.org (mailing list archive)
State Changes Requested, archived
Headers show
Series Allwinner sun6i message box support | expand

Commit Message

Samuel Holland Dec. 15, 2019, 4:24 a.m. UTC 
The msgbox clock is critical because the hardware it controls is shared
between Linux and system firmware. The message box may be used by the
EL3 secure monitor's PSCI implementation. On 64-bit sunxi SoCs, this is
provided by ARM TF-A; 32-bit SoCs use a different implementation. The
secure monitor uses the message box to forward requests to power
management firmware running on a separate CPU.

It is not enough for the secure monitor to enable the clock each time
Linux performs a SMC into EL3, as both the firmware and Linux can run
concurrently on separate CPUs. So it is never safe for Linux to turn
this clock off, and it should be marked as critical.

At this time, such power management firmware only exists for the A64 and
H5 SoCs.  However, it makes sense to take care of all CCU drivers now
for consistency, and to ease the transition in the future once firmware
is ported to the other SoCs.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun50i-h6.c  | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-a23.c  | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-a33.c  | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-a83t.c | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-h3.c   | 3 ++-
 drivers/clk/sunxi-ng/ccu-sun9i-a80.c  | 3 ++-
 7 files changed, 14 insertions(+), 7 deletions(-)

Comments

Maxime Ripard Dec. 16, 2019, 2 p.m. UTC | #1 
On Sat, Dec 14, 2019 at 10:24:48PM -0600, Samuel Holland wrote:
> The msgbox clock is critical because the hardware it controls is shared
> between Linux and system firmware. The message box may be used by the
> EL3 secure monitor's PSCI implementation. On 64-bit sunxi SoCs, this is
> provided by ARM TF-A; 32-bit SoCs use a different implementation. The
> secure monitor uses the message box to forward requests to power
> management firmware running on a separate CPU.
>
> It is not enough for the secure monitor to enable the clock each time
> Linux performs a SMC into EL3, as both the firmware and Linux can run
> concurrently on separate CPUs. So it is never safe for Linux to turn
> this clock off, and it should be marked as critical.
>
> At this time, such power management firmware only exists for the A64 and
> H5 SoCs.  However, it makes sense to take care of all CCU drivers now
> for consistency, and to ease the transition in the future once firmware
> is ported to the other SoCs.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>

This is pretty much the same case than for the AR100 clock though,
right?

I'm still not sure about why we should enable it that clock all the
time, even if you're not using the ARISC.

Maxime
diff mbox series

Patch

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 49bd7a4c015c..045121b50da3 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -342,8 +342,9 @@  static SUNXI_CCU_GATE(bus_de_clk,	"bus-de",	"ahb1",
 		      0x064, BIT(12), 0);
 static SUNXI_CCU_GATE(bus_gpu_clk,	"bus-gpu",	"ahb1",
 		      0x064, BIT(20), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x064, BIT(21), 0);
+		      0x064, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x064, BIT(22), 0);
 
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-h6.c b/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
index f2497d0a4683..91da52ca3c75 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
@@ -349,8 +349,9 @@  static SUNXI_CCU_GATE(bus_vp9_clk, "bus-vp9", "psi-ahb1-ahb2",
 static SUNXI_CCU_GATE(bus_dma_clk, "bus-dma", "psi-ahb1-ahb2",
 		      0x70c, BIT(0), 0);
 
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk, "bus-msgbox", "psi-ahb1-ahb2",
-		      0x71c, BIT(0), 0);
+		      0x71c, BIT(0), CLK_IS_CRITICAL);
 
 static SUNXI_CCU_GATE(bus_spinlock_clk, "bus-spinlock", "psi-ahb1-ahb2",
 		      0x72c, BIT(0), 0);
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a23.c b/drivers/clk/sunxi-ng/ccu-sun8i-a23.c
index 103aa504f6c8..5a28583f57e2 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a23.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a23.c
@@ -255,8 +255,9 @@  static SUNXI_CCU_GATE(bus_de_fe_clk,	"bus-de-fe",	"ahb1",
 		      0x064, BIT(14), 0);
 static SUNXI_CCU_GATE(bus_gpu_clk,	"bus-gpu",	"ahb1",
 		      0x064, BIT(20), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x064, BIT(21), 0);
+		      0x064, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x064, BIT(22), 0);
 static SUNXI_CCU_GATE(bus_drc_clk,	"bus-drc",	"ahb1",
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
index 91838cd11037..50cf3726ef30 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c
@@ -267,8 +267,9 @@  static SUNXI_CCU_GATE(bus_de_fe_clk,	"bus-de-fe",	"ahb1",
 		      0x064, BIT(14), 0);
 static SUNXI_CCU_GATE(bus_gpu_clk,	"bus-gpu",	"ahb1",
 		      0x064, BIT(20), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x064, BIT(21), 0);
+		      0x064, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x064, BIT(22), 0);
 static SUNXI_CCU_GATE(bus_drc_clk,	"bus-drc",	"ahb1",
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
index 2b434521c5cc..4ab3a76f4ffa 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
@@ -339,8 +339,9 @@  static SUNXI_CCU_GATE(bus_de_clk,	"bus-de",	"ahb1",
 		      0x064, BIT(12), 0);
 static SUNXI_CCU_GATE(bus_gpu_clk,	"bus-gpu",	"ahb1",
 		      0x064, BIT(20), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x064, BIT(21), 0);
+		      0x064, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x064, BIT(22), 0);
 
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
index 6b636362379e..7429d3fe8fb7 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
@@ -273,8 +273,9 @@  static SUNXI_CCU_GATE(bus_de_clk,	"bus-de",	"ahb1",
 		      0x064, BIT(12), 0);
 static SUNXI_CCU_GATE(bus_gpu_clk,	"bus-gpu",	"ahb1",
 		      0x064, BIT(20), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x064, BIT(21), 0);
+		      0x064, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x064, BIT(22), 0);
 
diff --git a/drivers/clk/sunxi-ng/ccu-sun9i-a80.c b/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
index ef29582676f6..471e841aabdf 100644
--- a/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
+++ b/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
@@ -748,8 +748,9 @@  static SUNXI_CCU_GATE(bus_usb_clk,	"bus-usb",	"ahb1",
 		      0x584, BIT(1), 0);
 static SUNXI_CCU_GATE(bus_gmac_clk,	"bus-gmac",	"ahb1",
 		      0x584, BIT(17), 0);
+/* Used for communication between firmware components at runtime */
 static SUNXI_CCU_GATE(bus_msgbox_clk,	"bus-msgbox",	"ahb1",
-		      0x584, BIT(21), 0);
+		      0x584, BIT(21), CLK_IS_CRITICAL);
 static SUNXI_CCU_GATE(bus_spinlock_clk,	"bus-spinlock",	"ahb1",
 		      0x584, BIT(22), 0);
 static SUNXI_CCU_GATE(bus_hstimer_clk,	"bus-hstimer",	"ahb1",