On Thu, Oct 21, 2021 at 03:01:06PM +0530, Sanket Goswami wrote: > STB (Smart Trace Buffer), is a debug trace buffer which is used to help > isolate failures by analyzing the last feature that a system was running > before hitting a failure. This nonintrusive way is always running in the > background and trace is stored into the SoC. > > This patch provides mechanism to access the STB buffer using the read > and write routines. I don't see the write routine exported. > > 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 v2: > - Create amd_pmc_stb_debugfs_fops structure to get STB data. > - Address review comments from Hans. > > drivers/platform/x86/amd-pmc.c | 120 +++++++++++++++++++++++++++++++++ > 1 file changed, 120 insertions(+) > > diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c > index 502f37eaba1f..df53c5996e2c 100644 > --- a/drivers/platform/x86/amd-pmc.c > +++ b/drivers/platform/x86/amd-pmc.c > @@ -33,6 +33,12 @@ > #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 > @@ -80,6 +86,7 @@ > #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, > @@ -126,8 +133,14 @@ 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, bool set, u32 *data, u8 msg, bool ret); > +static int amd_pmc_write_stb(struct amd_pmc_dev *dev, u32 data); shouldn't this be exported as a kernel API to log stuff? seems like a waist to only log the pmc suspend resume status. > +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) > { > @@ -156,6 +169,51 @@ struct smu_metrics { > u64 timecondition_notmet_totaltime[SOC_SUBSYSTEM_IP_MAX]; > } __packed; > > +static int amd_pmc_stb_debugfs_open(struct inode *inode, struct file *filp) > +{ > + struct amd_pmc_dev *dev = filp->f_inode->i_private; > + u32 *buf; > + int rc; > + > + buf = devm_kmalloc(dev->dev, FIFO_SIZE * 4, GFP_KERNEL); would it be more readable to use sizeof(u32)? > + if (!buf) > + return -ENOMEM; > + > + rc = amd_pmc_read_stb(dev, buf); > + if (rc) > + goto out; > + > + filp->private_data = buf; > + > +out: > + 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 * 4); would it be more readable to use sizeof(u32)? > +} > + > +static int amd_pmc_stb_debugfs_release(struct inode *inode, struct file *filp) > +{ > + kfree(filp->private_data); > + filp->private_data = NULL; > + > + 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, are you missing a write fop? you commit comment talked about a write routine. > +}; > + > static int amd_pmc_idlemask_read(struct amd_pmc_dev *pdev, struct device *dev, > struct seq_file *s) > { > @@ -269,6 +327,10 @@ 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) > @@ -430,6 +492,9 @@ static int __maybe_unused amd_pmc_suspend(struct device *dev) > if (rc) > dev_err(pdev->dev, "suspend failed\n"); > > + if (enable_stb) > + amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF); > + > return rc; > } > > @@ -450,6 +515,10 @@ 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) > + amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1); > + > return 0; > } > > @@ -466,6 +535,57 @@ static const struct pci_device_id pmc_pci_ids[] = { > { } > }; > > +static int amd_pmc_write_stb(struct amd_pmc_dev *dev, u32 data) > +{ > + int rc; > + > + rc = pci_write_config_dword(dev->rdev, AMD_PMC_STB_INDEX_ADDRESS, AMD_PMC_STB_PMI_0); > + if (rc) { > + dev_err(dev->dev, "failed to write addr in stb: 0x%X\n", > + AMD_PMC_STB_INDEX_ADDRESS); > + pci_dev_put(dev->rdev); > + return pcibios_err_to_errno(rc); > + } > + > + rc = pci_write_config_dword(dev->rdev, AMD_PMC_STB_INDEX_DATA, data); > + if (rc) { > + dev_err(dev->dev, "failed to write data in stb: 0x%X\n", > + AMD_PMC_STB_INDEX_DATA); > + pci_dev_put(dev->rdev); > + return pcibios_err_to_errno(rc); > + } > + > + return 0; > +} > + > +static int amd_pmc_read_stb(struct amd_pmc_dev *dev, u32 *buf) > +{ > + int i, err; > + u32 value; > + > + 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); > + pci_dev_put(dev->rdev); > + return pcibios_err_to_errno(err); > + } > + > + for (i = 0; i < FIFO_SIZE; i++) { > + err = pci_read_config_dword(dev->rdev, AMD_PMC_STB_INDEX_DATA, &value); > + if (err) { > + dev_err(dev->dev, "error reading data from stb: 0x%X\n", > + AMD_PMC_STB_INDEX_DATA); > + pci_dev_put(dev->rdev); > + return pcibios_err_to_errno(err); > + } > + > + *buf++ = value; > + } > + > + return 0; > +} > + > static int amd_pmc_probe(struct platform_device *pdev) > { > struct amd_pmc_dev *dev = &pmc; > -- > 2.25.1 >