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Subject[PATCH 1/2] tpm: do not suspend/resume if power stays on
Date
From: Enric Balletbo i Serra <enric.balletbo@collabora.com>

commit b5d0ebc99bf5d0801a5ecbe958caa3d68b8eaee8 upstream

The suspend/resume behavior of the TPM can be controlled by setting
"powered-while-suspended" in the DTS. This is useful for the cases
when hardware does not power-off the TPM.

Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
---
drivers/char/tpm/tpm-interface.c | 3 +++
drivers/char/tpm/tpm.h | 2 ++
drivers/char/tpm/tpm_of.c | 3 +++
3 files changed, 8 insertions(+)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 830d7e30e508..5463b649bdf1 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -969,6 +969,9 @@ int tpm_pm_suspend(struct device *dev)
if (chip == NULL)
return -ENODEV;

+ if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
+ return 0;
+
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
tpm2_shutdown(chip, TPM2_SU_STATE);
return 0;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index aa4299cf7e5a..41756a9e9ad8 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -143,6 +143,8 @@ enum tpm_chip_flags {
TPM_CHIP_FLAG_TPM2 = BIT(1),
TPM_CHIP_FLAG_IRQ = BIT(2),
TPM_CHIP_FLAG_VIRTUAL = BIT(3),
+ TPM_CHIP_FLAG_HAVE_TIMEOUTS = BIT(4),
+ TPM_CHIP_FLAG_ALWAYS_POWERED = BIT(5),
};

struct tpm_chip {
diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 570f30c5c5f4..669f4a046398 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -37,6 +37,9 @@ int read_log(struct tpm_bios_log *log)
return -ENODEV;
}

+ if (of_property_read_bool(np, "powered-while-suspended"))
+ chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
+
sizep = of_get_property(np, "linux,sml-size", NULL);
if (sizep == NULL) {
pr_err("%s: ERROR - SML size not found\n", __func__);
--
2.17.0
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