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Date: Fri, 16 Jun 2023 10:13:37 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
cc: hdegoede@...hat.com, markgross@...nel.org,
platform-driver-x86@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 1/2] platform/x86/intel/tpmi: Read feature control
status
On Thu, 15 Jun 2023, Srinivas Pandruvada wrote:
> 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@...ux.intel.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
> As suggested by Dan Williams changed ioremap to devm_ioremap() after
> review by Andy.
>
> drivers/platform/x86/intel/tpmi.c | 147 ++++++++++++++++++++++++++++++
> include/linux/intel_tpmi.h | 2 +
> 2 files changed, 149 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/tpmi.c b/drivers/platform/x86/intel/tpmi.c
> index a5227951decc..9545e9cdb924 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;
> };
>
> /**
> @@ -139,6 +144,7 @@ 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 */
> };
>
> @@ -175,6 +181,144 @@ 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
> +#define TPMI_DATA_OFFSET 0x0C
> +/*
> + * 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
> +
> +#define TPMI_OWNER_NONE 0
> +#define TPMI_OWNER_IN_BAND 1
> +
> +#define TPMI_GENMASK_OWNER GENMASK_ULL(5, 4)
> +#define TPMI_GENMASK_STATUS GENMASK_ULL(15, 8)
> +
> +#define TPMI_GET_STATE_CMD 0x10
> +#define TPMI_GET_STATE_CMD_DATA_OFFSET 8
> +#define TPMI_CMD_DATA_OFFSET 32
> +#define TPMI_CMD_PKT_LEN_OFFSET 16
> +#define TPMI_CMD_PKT_LEN 2
> +#define TPMI_CONTROL_RB_BIT 0
> +#define TPMI_CONTROL_CPL_BIT 6
> +#define TPMI_CMD_STATUS_SUCCESS 0x40
> +#define TPMI_GET_STATUS_BIT_ENABLE 0
> +#define TPMI_GET_STATUS_BIT_LOCKED 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_GENMASK_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);
> +
> + 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 = TPMI_GET_STATE_CMD;
> + /* 32 bits for DATA offset and +8 for feature_id field */
> + data |= ((u64)feature_id << (TPMI_CMD_DATA_OFFSET + TPMI_GET_STATE_CMD_DATA_OFFSET));
This looks like you should add the GENMASK_ULL() for the fields and use
FIELD_PREP() instead of adding all those OFFSET defines + custom shifting.
> +
> + /* Write at command offset for qword access */
> + writeq(data, tpmi_info->tpmi_control_mem + TPMI_COMMAND_OFFSET);
> +
> + 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 */
> + writeq(BIT_ULL(TPMI_CONTROL_RB_BIT) | (TPMI_CMD_PKT_LEN << TPMI_CMD_PKT_LEN_OFFSET),
Define using BIT_ULL(0) instead. Use FIELD_PREP().
I'd drop _BIT from the define name but I leave it up to you, it just
makes your lines longer w/o much added value.
> + tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
> +
> + ret = read_poll_timeout(readq, control, !(control & BIT_ULL(TPMI_CONTROL_RB_BIT)),
> + 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_GENMASK_STATUS, control);
> + if (control != TPMI_CMD_STATUS_SUCCESS) {
> + ret = -EBUSY;
> + goto done_proc;
> + }
> +
> + data = readq(tpmi_info->tpmi_control_mem + TPMI_COMMAND_OFFSET);
> + data >>= TPMI_CMD_DATA_OFFSET; /* Upper 32 bits are for TPMI_DATA */
Define the field with GENMASK() and use FIELD_GET().
> +
> + *disabled = 0;
> + *locked = 0;
> +
> + if (!(data & BIT_ULL(TPMI_GET_STATUS_BIT_ENABLE)))
Put BIT_ULL() into the define.
Perhaps drop _BIT_ from the name.
> + *disabled = 1;
> +
> + if (data & BIT_ULL(TPMI_GET_STATUS_BIT_LOCKED))
Ditto.
> + *locked = 1;
> +
> + ret = 0;
> +
> +done_proc:
> + /* SET CPL "completion"bit */
Missing space.
> + writeq(BIT_ULL(TPMI_CONTROL_CPL_BIT),
BIT_ULL() to define.
> + 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;
> + u16 size;
> +
> + size = pfs->pfs_header.num_entries * pfs->pfs_header.entry_size * 4;
Can this overflow u16? Where does pfs_header content originate from? If
from HW, how is it the input validated?
--
i.
> + 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 +511,9 @@ 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
>
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