STB (Smart Trace Buffer), is a debug trace buffer that isolates the
failures by analyzing the last running feature of a system. This
non-intrusive way always runs in the background and stores the trace
into the SoC.
This patch enables the STB feature by passing module param
"enable_stb=1" while loading the driver and provides mechanism to
access the STB buffer using the read and write routines.
Co-developed-by: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx>
Signed-off-by: Sanket Goswami <Sanket.Goswami@xxxxxxx>
---
Changes in v6:
- Capture the read data directly into buf in amd_pmc_read_stb().
Changes in v5:
- Use kfree() only once in .open as suggested by Hans.
Changes in v4:
- Use kzalloc() for memory allocation.
Changes in v3:
- Use sizeof(u32) with multiplier as suggested by Mark Gross.
Changes in v2:
- Create amd_pmc_stb_debugfs_fops structure to get STB data.
- Address review comments from Hans.
drivers/platform/x86/amd-pmc.c | 132 +++++++++++++++++++++++++++++++++
1 file changed, 132 insertions(+)
diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
index b3b8a5daa02e..581cfd702082 100644
--- a/drivers/platform/x86/amd-pmc.c
+++ b/drivers/platform/x86/amd-pmc.c
@@ -35,6 +35,12 @@
#define AMD_PMC_SCRATCH_REG_CZN 0x94
#define AMD_PMC_SCRATCH_REG_YC 0xD14
+/* STB Registers */
+#define AMD_PMC_STB_INDEX_ADDRESS 0xF8
+#define AMD_PMC_STB_INDEX_DATA 0xFC
+#define AMD_PMC_STB_PMI_0 0x03E30600
+#define AMD_PMC_STB_PREDEF 0xC6000001
+
/* Base address of SMU for mapping physical address to virtual address */
#define AMD_PMC_SMU_INDEX_ADDRESS 0xB8
#define AMD_PMC_SMU_INDEX_DATA 0xBC
@@ -82,6 +88,7 @@
#define SOC_SUBSYSTEM_IP_MAX 12
#define DELAY_MIN_US 2000
#define DELAY_MAX_US 3000
+#define FIFO_SIZE 4096
enum amd_pmc_def {
MSG_TEST = 0x01,
MSG_OS_HINT_PCO,
@@ -128,8 +135,14 @@ struct amd_pmc_dev {
#endif /* CONFIG_DEBUG_FS */
};
+static bool enable_stb;
+module_param(enable_stb, bool, 0644);
+MODULE_PARM_DESC(enable_stb, "Enable the STB debug mechanism");
+
static struct amd_pmc_dev pmc;
static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, u32 arg, u32 *data, u8 msg, bool ret);
+static int amd_pmc_write_stb(struct amd_pmc_dev *dev, u32 data);
+static int amd_pmc_read_stb(struct amd_pmc_dev *dev, u32 *buf);
static inline u32 amd_pmc_reg_read(struct amd_pmc_dev *dev, int reg_offset)
{
@@ -176,6 +189,50 @@ static int amd_pmc_get_smu_version(struct amd_pmc_dev *dev)
return 0;
}
+static int amd_pmc_stb_debugfs_open(struct inode *inode, struct file *filp)
+{
+ struct amd_pmc_dev *dev = filp->f_inode->i_private;
+ u32 size = FIFO_SIZE * sizeof(u32);
+ u32 *buf;
+ int rc;
+
+ buf = kzalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ rc = amd_pmc_read_stb(dev, buf);
+ if (rc) {
+ kfree(buf);
+ return rc;
+ }
+
+ filp->private_data = buf;
+ return rc;
+}
+
+static ssize_t amd_pmc_stb_debugfs_read(struct file *filp, char __user *buf, size_t size,
+ loff_t *pos)
+{
+ if (!filp->private_data)
+ return -EINVAL;
+
+ return simple_read_from_buffer(buf, size, pos, filp->private_data,
+ FIFO_SIZE * sizeof(u32));
+}
+
+static int amd_pmc_stb_debugfs_release(struct inode *inode, struct file *filp)
+{
+ kfree(filp->private_data);
+ return 0;
+}
+
+const struct file_operations amd_pmc_stb_debugfs_fops = {
+ .owner = THIS_MODULE,
+ .open = amd_pmc_stb_debugfs_open,
+ .read = amd_pmc_stb_debugfs_read,
+ .release = amd_pmc_stb_debugfs_release,
+};
+
static int amd_pmc_idlemask_read(struct amd_pmc_dev *pdev, struct device *dev,
struct seq_file *s)
{
@@ -289,6 +346,10 @@ static void amd_pmc_dbgfs_register(struct amd_pmc_dev *dev)
&s0ix_stats_fops);
debugfs_create_file("amd_pmc_idlemask", 0644, dev->dbgfs_dir, dev,
&amd_pmc_idlemask_fops);
+ /* Enable STB only when the module_param is set */
+ if (enable_stb)
+ debugfs_create_file("stb_read", 0644, dev->dbgfs_dir, dev,
+ &amd_pmc_stb_debugfs_fops);
}
#else
static inline void amd_pmc_dbgfs_register(struct amd_pmc_dev *dev)
@@ -485,6 +546,13 @@ static int __maybe_unused amd_pmc_suspend(struct device *dev)
if (rc)
dev_err(pdev->dev, "suspend failed\n");
+ if (enable_stb)
+ rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF);
+ if (rc) {
+ dev_err(pdev->dev, "error writing to STB\n");
+ return rc;
+ }
+
return rc;
}
@@ -505,6 +573,14 @@ static int __maybe_unused amd_pmc_resume(struct device *dev)
/* Dump the IdleMask to see the blockers */
amd_pmc_idlemask_read(pdev, dev, NULL);
+ /* Write data incremented by 1 to distinguish in stb_read */
+ if (enable_stb)
+ rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1);
+ if (rc) {
+ dev_err(pdev->dev, "error writing to STB\n");
+ return rc;
+ }
+
return 0;
}
@@ -521,6 +597,62 @@ static const struct pci_device_id pmc_pci_ids[] = {
{ }
};
+static int amd_pmc_write_stb(struct amd_pmc_dev *dev, u32 data)
+{
+ int err;
+
+ err = pci_write_config_dword(dev->rdev, AMD_PMC_STB_INDEX_ADDRESS, AMD_PMC_STB_PMI_0);
+ if (err) {
+ dev_err(dev->dev, "failed to write addr in stb: 0x%X\n",
+ AMD_PMC_STB_INDEX_ADDRESS);
+ err = pcibios_err_to_errno(err);
+ goto err_pci_dev_put;
+ }
+
+ err = pci_write_config_dword(dev->rdev, AMD_PMC_STB_INDEX_DATA, data);
+ if (err) {
+ dev_err(dev->dev, "failed to write data in stb: 0x%X\n",
+ AMD_PMC_STB_INDEX_DATA);
+ err = pcibios_err_to_errno(err);
+ goto err_pci_dev_put;
+ }
+
+ return 0;
+
+err_pci_dev_put:
+ pci_dev_put(dev->rdev);
+ return err;
+}
+
+static int amd_pmc_read_stb(struct amd_pmc_dev *dev, u32 *buf)
+{
+ int i, err;
+
+ err = pci_write_config_dword(dev->rdev, AMD_PMC_STB_INDEX_ADDRESS, AMD_PMC_STB_PMI_0);
+ if (err) {
+ dev_err(dev->dev, "error writing addr to stb: 0x%X\n",
+ AMD_PMC_STB_INDEX_ADDRESS);
+ err = pcibios_err_to_errno(err);
+ goto err_pci_dev_put;
+ }
+
+ for (i = 0; i < FIFO_SIZE; i++) {
+ err = pci_read_config_dword(dev->rdev, AMD_PMC_STB_INDEX_DATA, buf++);
+ if (err) {
+ dev_err(dev->dev, "error reading data from stb: 0x%X\n",
+ AMD_PMC_STB_INDEX_DATA);
+ err = pcibios_err_to_errno(err);
+ goto err_pci_dev_put;
+ }
+ }
+
+ return 0;
+
+err_pci_dev_put:
+ pci_dev_put(dev->rdev);
+ return err;
+}
+
static int amd_pmc_probe(struct platform_device *pdev)
{
struct amd_pmc_dev *dev = &pmc;
--
2.25.1
