[PATCH v2 1/3] platform/x86/intel/tpmi: Read feature control status

Srinivas Pandruvada
2023-07-11T22:10:07Z

Some of the PM features can be locked or disabled. In that case, write
interface can be locked.

This status is read via a mailbox. There is one TPMI ID which provides
base address for interface and data register for mail box operation.
The mailbox operations is defined in the TPMI specification. Refer to
https://github.com/intel/tpmi_power_management/ for TPMI specifications.

An API is exposed to feature drivers to read feature control status.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
The external interface will be used by all feature drivers, will
submit patch for that.

v2
- Renaming of register names as suggested by llpo
- cosmetic changes as suggested by llpo
- size change to u32 for checking with max 4K size

v1
This has all changes suggested by Andi

drivers/platform/x86/intel/tpmi.c | 178 ++++++++++++++++++++++++++++++
include/linux/intel_tpmi.h | 2 +
2 files changed, 180 insertions(+)

diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
index d1fd6e69401c..024e7671687a 100644
--- a/drivers/platform/x86/intel/tpmi.c
+++ b/drivers/platform/x86/intel/tpmi.c
@@ -47,8 +47,11 @@
*/

#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/delay.h>
#include <linux/intel_tpmi.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/pci.h>

@@ -98,6 +101,7 @@ struct intel_tpmi_pm_feature {
* @feature_count: Number of TPMI of TPMI instances pointed by tpmi_features
* @pfs_start: Start of PFS offset for the TPMI instances in this device
* @plat_info: Stores platform info which can be used by the client drivers
+ * @tpmi_control_mem: Memory mapped IO for getting control information
*
* Stores the information for all TPMI devices enumerated from a single PCI device.
*/
@@ -107,6 +111,7 @@ struct intel_tpmi_info {
int feature_count;
u64 pfs_start;
struct intel_tpmi_plat_info plat_info;
+ void __iomem *tpmi_control_mem;
};

/**
@@ -139,9 +144,16 @@ enum intel_tpmi_id {
TPMI_ID_PEM = 1, /* Power and Perf excursion Monitor */
TPMI_ID_UNCORE = 2, /* Uncore Frequency Scaling */
TPMI_ID_SST = 5, /* Speed Select Technology */
+ TPMI_CONTROL_ID = 0x80, /* Special ID for getting feature status */
TPMI_INFO_ID = 0x81, /* Special ID for PCI BDF and Package ID information */
};

+/*
+ * TPMI PFS and per feature memory size can't exceed 4K.
+ * Also PFS start and feature memory is 4K aligned.
+ */
+#define TPMI_MAX_BUFFER_SIZE (4 * 1024)
+
/* Used during auxbus device creation */
static DEFINE_IDA(intel_vsec_tpmi_ida);

@@ -175,6 +187,169 @@ struct resource *tpmi_get_resource_at_index(struct auxiliary_device *auxdev, int
}
EXPORT_SYMBOL_NS_GPL(tpmi_get_resource_at_index, INTEL_TPMI);

+/* TPMI Control Interface */
+
+#define TPMI_CONTROL_STATUS_OFFSET 0x00
+#define TPMI_COMMAND_OFFSET 0x08
+
+/*
+ * Spec is calling for max 1 seconds to get ownership at the worst
+ * case. Read at 10 ms timeouts and repeat up to 1 second.
+ */
+#define TPMI_CONTROL_TIMEOUT_US (10 * USEC_PER_MSEC)
+#define TPMI_CONTROL_TIMEOUT_MAX_US USEC_PER_SEC
+
+#define TPMI_RB_TIMEOUT_US (10 * USEC_PER_MSEC)
+#define TPMI_RB_TIMEOUT_MAX_US USEC_PER_SEC
+
+/* TPMI Control status register defines */
+
+#define TPMI_CONTROL_STATUS_RB BIT_ULL(0)
+
+#define TPMI_CONTROL_STATUS_OWNER GENMASK_ULL(5, 4)
+#define TPMI_OWNER_NONE 0
+#define TPMI_OWNER_IN_BAND 1
+
+#define TPMI_CONTROL_STATUS_CPL BIT_ULL(6)
+#define TPMI_CONTROL_STATUS_RESULT GENMASK_ULL(15, 8)
+#define TPMI_CONTROL_STATUS_LEN GENMASK_ULL(31, 16)
+
+#define TPMI_CMD_PKT_LEN 2
+#define TPMI_CMD_STATUS_SUCCESS 0x40
+
+/* TPMI command data registers */
+#define TMPI_CONTROL_DATA_CMD GENMASK_ULL(7, 0)
+#define TMPI_CONTROL_DATA_VAL GENMASK_ULL(63, 32)
+#define TPMI_CONTROL_DATA_VAL_FEATURE GENMASK_ULL(48, 40)
+
+/* Command to send via control interface */
+#define TPMI_CONTROL_GET_STATE_CMD 0x10
+
+#define TPMI_CONTROL_CMD_MASK GENMASK_ULL(48, 40)
+
+#define TPMI_CMD_LEN_MASK GENMASK_ULL(18, 16)
+
+#define TPMI_STATE_DISABLED BIT_ULL(0)
+#define TPMI_STATE_LOCKED BIT_ULL(31)
+
+/* Mutex to complete get feature status without interruption */
+static DEFINE_MUTEX(tpmi_dev_lock);
+
+static int tpmi_wait_for_owner(struct intel_tpmi_info *tpmi_info, u8 owner)
+{
+ u64 control;
+
+ return read_poll_timeout(readq, control,
+ owner == FIELD_GET(TPMI_CONTROL_STATUS_OWNER, control),
+ TPMI_CONTROL_TIMEOUT_US, TPMI_CONTROL_TIMEOUT_MAX_US, false,
+ tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
+}
+
+static int tpmi_read_feature_status(struct intel_tpmi_info *tpmi_info, int feature_id,
+ int *locked, int *disabled)
+{
+ u64 control, data;
+ int ret;
+
+ if (!tpmi_info->tpmi_control_mem)
+ return -EFAULT;
+
+ mutex_lock(&tpmi_dev_lock);
+
+ /* Wait for owner bit set to 0 (none) */
+ ret = tpmi_wait_for_owner(tpmi_info, TPMI_OWNER_NONE);
+ if (ret)
+ goto err_unlock;
+
+ /* set command id to 0x10 for TPMI_GET_STATE */
+ data = FIELD_PREP(TMPI_CONTROL_DATA_CMD, TPMI_CONTROL_GET_STATE_CMD);
+
+ /* 32 bits for DATA offset and +8 for feature_id field */
+ data |= FIELD_PREP(TPMI_CONTROL_DATA_VAL_FEATURE, feature_id);
+
+ /* Write at command offset for qword access */
+ writeq(data, tpmi_info->tpmi_control_mem + TPMI_COMMAND_OFFSET);
+
+ /* Wait for owner bit set to in-band */
+ ret = tpmi_wait_for_owner(tpmi_info, TPMI_OWNER_IN_BAND);
+ if (ret)
+ goto err_unlock;
+
+ /* Set Run Busy and packet length of 2 dwords */
+ control = TPMI_CONTROL_STATUS_RB;
+ control |= FIELD_PREP(TPMI_CONTROL_STATUS_LEN, TPMI_CMD_PKT_LEN);
+
+ /* Write at status offset for qword access */
+ writeq(control, tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
+
+ /* Wait for Run Busy clear */
+ ret = read_poll_timeout(readq, control, !(control & TPMI_CONTROL_STATUS_RB),
+ TPMI_RB_TIMEOUT_US, TPMI_RB_TIMEOUT_MAX_US, false,
+ tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
+ if (ret)
+ goto done_proc;
+
+ control = FIELD_GET(TPMI_CONTROL_STATUS_RESULT, control);
+ if (control != TPMI_CMD_STATUS_SUCCESS) {
+ ret = -EBUSY;
+ goto done_proc;
+ }
+
+ /* Response is ready */
+ data = readq(tpmi_info->tpmi_control_mem + TPMI_COMMAND_OFFSET);
+ data = FIELD_GET(TMPI_CONTROL_DATA_VAL, data);
+
+ *disabled = 0;
+ *locked = 0;
+
+ if (!(data & TPMI_STATE_DISABLED))
+ *disabled = 1;
+
+ if (data & TPMI_STATE_LOCKED)
+ *locked = 1;
+
+ ret = 0;
+
+done_proc:
+ /* Set CPL "completion" bit */
+ writeq(TPMI_CONTROL_STATUS_CPL, tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
+
+err_unlock:
+ mutex_unlock(&tpmi_dev_lock);
+
+ return ret;
+}
+
+int tpmi_get_feature_status(struct auxiliary_device *auxdev, int feature_id,
+ int *locked, int *disabled)
+{
+ struct intel_vsec_device *intel_vsec_dev = dev_to_ivdev(auxdev->dev.parent);
+ struct intel_tpmi_info *tpmi_info = auxiliary_get_drvdata(&intel_vsec_dev->auxdev);
+
+ return tpmi_read_feature_status(tpmi_info, feature_id, locked, disabled);
+}
+EXPORT_SYMBOL_NS_GPL(tpmi_get_feature_status, INTEL_TPMI);
+
+static void tpmi_set_control_base(struct auxiliary_device *auxdev,
+ struct intel_tpmi_info *tpmi_info,
+ struct intel_tpmi_pm_feature *pfs)
+{
+ void __iomem *mem;
+ u32 size;
+
+ size = pfs->pfs_header.num_entries * pfs->pfs_header.entry_size * sizeof(u32);
+ /* This size is coming from trusted hardware, but verify anyway */
+ if (size > TPMI_MAX_BUFFER_SIZE)
+ return;
+
+ mem = devm_ioremap(&auxdev->dev, pfs->vsec_offset, size);
+ if (!mem)
+ return;
+
+ /* mem is pointing to TPMI CONTROL base */
+ tpmi_info->tpmi_control_mem = mem;
+}
+
static const char *intel_tpmi_name(enum intel_tpmi_id id)
{
switch (id) {
@@ -367,6 +542,9 @@ static int intel_vsec_tpmi_init(struct auxiliary_device *auxdev)
*/
if (pfs->pfs_header.tpmi_id == TPMI_INFO_ID)
tpmi_process_info(tpmi_info, pfs);
+
+ if (pfs->pfs_header.tpmi_id == TPMI_CONTROL_ID)
+ tpmi_set_control_base(auxdev, tpmi_info, pfs);
}

tpmi_info->pfs_start = pfs_start;
diff --git a/include/linux/intel_tpmi.h b/include/linux/intel_tpmi.h
index f505788c05da..04d937ad4dc4 100644
--- a/include/linux/intel_tpmi.h
+++ b/include/linux/intel_tpmi.h
@@ -27,4 +27,6 @@ struct intel_tpmi_plat_info *tpmi_get_platform_data(struct auxiliary_device *aux
struct resource *tpmi_get_resource_at_index(struct auxiliary_device *auxdev, int index);
int tpmi_get_resource_count(struct auxiliary_device *auxdev);

+int tpmi_get_feature_status(struct auxiliary_device *auxdev, int feature_id, int *locked,
+ int *disabled);
#endif
--
2.40.1