firmware: tegra: Add suspend hook and reset BPMP IPC early on resume

Add suspend hook and a 'suspended' field in the 'struct tegra_bpmp'
to mark if BPMP is suspended. Also, add a 'flags' field in the
'struct tegra_bpmp_message' whose 'TEGRA_BPMP_MESSAGE_RESET' bit can be
set from the Tegra MC driver to signal that the reset of BPMP IPC
channels is required before sending MRQ to the BPMP FW. Together both
the fields allow us to handle any requests that might be sent too soon
as they can cause hang during system resume.

One case where we see BPMP requests being sent before the BPMP driver
has resumed is the memory bandwidth requests which are triggered by
onlining the CPUs during system resume. The CPUs are onlined before the
BPMP has resumed and we need to reset the BPMP IPC channels to handle
these requests.

The additional check for 'flags' is done to avoid any un-intended BPMP
IPC reset if the tegra_bpmp_transfer*() API gets called during suspend
sequence after the BPMP driver is suspended.

Fixes: f41e1442ac5b ("cpufreq: tegra194: add OPP support and set bandwidth")
Co-developed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/soc/tegra/bpmp.h b/include/soc/tegra/bpmp.h
index 5842e38bb288..f5e4ac5b8cce 100644
--- a/include/soc/tegra/bpmp.h
+++ b/include/soc/tegra/bpmp.h
@@ -102,8 +102,12 @@ struct tegra_bpmp {
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_mirror;
 #endif
+
+	bool suspended;
 };
 
+#define TEGRA_BPMP_MESSAGE_RESET BIT(0)
+
 struct tegra_bpmp_message {
 	unsigned int mrq;
 
@@ -117,6 +121,8 @@ struct tegra_bpmp_message {
 		size_t size;
 		int ret;
 	} rx;
+
+	unsigned long flags;
 };
 
 #if IS_ENABLED(CONFIG_TEGRA_BPMP)