[PATCH v2 1/5] pmt: Add register access callbacks

["Michael J. Ruhl" <michael.j.ruhl@intel.com>]

Some HW does not have direct MMIO access to PMT control and data
features.

Augment the current callback infrastructure (data access) to allow
a registered driver to customize read/write access to the control
paths for PMT usage.

Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
---
 drivers/platform/x86/intel/pmt/crashlog.c | 39 +++++++++++++++++++++--
 include/linux/intel_vsec.h                | 26 +++++++++++----
 2 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/x86/intel/pmt/crashlog.c b/drivers/platform/x86/intel/pmt/crashlog.c
index b0393c9c5b4b..e4778068b068 100644
--- a/drivers/platform/x86/intel/pmt/crashlog.c
+++ b/drivers/platform/x86/intel/pmt/crashlog.c
@@ -129,7 +129,19 @@ static void pmt_crashlog_rmw(struct crashlog_entry *crashlog, u32 bit, bool set)
 {
 	const struct crashlog_control *control = &crashlog->info->control;
 	struct intel_pmt_entry *entry = &crashlog->entry;
-	u32 reg = readl(entry->disc_table + control->offset);
+	u32 guid = entry->header.guid;
+	u32 reg;
+	int err;
+
+	if (entry->cb->read_reg) {
+		err = entry->cb->read_reg(entry->pcidev, guid, &reg, control->offset);
+		if (err) {
+			pr_err("failed to read reg: %d\n", err);
+			return;
+		}
+	} else {
+		reg = readl(entry->disc_table + control->offset);
+	}
 
 	reg &= ~control->trigger_mask;
 
@@ -138,14 +150,35 @@ static void pmt_crashlog_rmw(struct crashlog_entry *crashlog, u32 bit, bool set)
 	else
 		reg &= ~bit;
 
-	writel(reg, entry->disc_table + control->offset);
+	if (entry->cb->write_reg) {
+		err = entry->cb->write_reg(entry->pcidev, guid, reg, control->offset);
+		if (err) {
+			pr_err("failed to write reg: %d\n", err);
+			return;
+		}
+	} else {
+		writel(reg, entry->disc_table + control->offset);
+	}
 }
 
 /* Read the status register and see if the specified @bit is set */
 static bool pmt_crashlog_rc(struct crashlog_entry *crashlog, u32 bit)
 {
 	const struct crashlog_status *status = &crashlog->info->status;
-	u32 reg = readl(crashlog->entry.disc_table + status->offset);
+	struct intel_pmt_entry *entry = &crashlog->entry;
+	u32 guid = entry->header.guid;
+	u32 reg;
+	int err;
+
+	if (entry->cb->read_reg) {
+		err = entry->cb->read_reg(entry->pcidev, guid, &reg, status->offset);
+		if (err) {
+			pr_err("failed to read reg: %d\n", err);
+			return false;
+		}
+	} else {
+		reg = readl(crashlog->entry.disc_table + status->offset);
+	}
 
 	return !!(reg & bit);
 }
diff --git a/include/linux/intel_vsec.h b/include/linux/intel_vsec.h
index 1a0f357c2427..c9b7aa860d0b 100644
--- a/include/linux/intel_vsec.h
+++ b/include/linux/intel_vsec.h
@@ -80,16 +80,28 @@ enum intel_vsec_quirks {
 
 /**
  * struct pmt_callbacks - Callback infrastructure for PMT devices
- * @read_telem: when specified, called by client driver to access PMT
- * data (instead of direct copy).
- * * pdev:  PCI device reference for the callback's use
- * * guid:  ID of data to acccss
- * * data:  buffer for the data to be copied
- * * off:   offset into the requested buffer
- * * count: size of buffer
+ * @read_telem: when specified, called by client driver to access PMT data (instead
+ * of direct copy).
+ * @pdev:  PCI device reference for the callback's use
+ * @guid:  ID of data to access
+ * @data:  buffer for the data to be copied
+ * @off:   offset into the requested buffer
+ * @count: size of buffer
+ * @read_reg: when specified called by client driver to read PMT state
+ * @pdev: PCI device reference for the callback's use
+ * @guid: ID of data to access
+ * @data: buffer for the register data to be read
+ * @offset: offset of control register to access
+ * @write_reg: when specified called by client driver to write PMT state
+ * @pdev: PCI device reference for the callback's use
+ * @guid: ID of data to access
+ * @data: buffer data to be written to the register
+ * @offset: offset of control register to access
  */
 struct pmt_callbacks {
 	int (*read_telem)(struct pci_dev *pdev, u32 guid, u64 *data, loff_t off, u32 count);
+	int (*read_reg)(struct pci_dev *pdev, u32 guid, u32 *data, u32 offset);
+	int (*write_reg)(struct pci_dev *pdev, u32 guid, u32 data, u32 offset);
 };
 
 struct vsec_feature_dependency {
-- 
2.52.0