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Wed, 19 Feb 2025 22:06:59 -0800 (PST) Date: Thu, 20 Feb 2025 11:36:50 +0530 From: Manivannan Sadhasivam To: Shradha Todi Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, lpieralisi@kernel.org, kw@linux.com, robh@kernel.org, bhelgaas@google.com, jingoohan1@gmail.com, Jonathan.Cameron@Huawei.com, fan.ni@samsung.com, nifan.cxl@gmail.com, a.manzanares@samsung.com, pankaj.dubey@samsung.com, cassel@kernel.org, 18255117159@163.com, quic_nitegupt@quicinc.com, quic_krichai@quicinc.com, gost.dev@samsung.com Subject: Re: [PATCH v6 3/4] Add debugfs based error injection support in DWC Message-ID: <20250220060650.sqioighxfputkifs@thinkpad> References: <20250214105007.97582-1-shradha.t@samsung.com> <20250214105007.97582-4-shradha.t@samsung.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250214105007.97582-4-shradha.t@samsung.com> On Fri, Feb 14, 2025 at 04:20:06PM +0530, Shradha Todi wrote: > Add support to provide error injection interface to userspace. This set > of debug registers are part of the RASDES feature present in DesignWare > PCIe controllers. > > Signed-off-by: Shradha Todi Reviewed-by: Manivannan Sadhasivam - Mani > --- > Documentation/ABI/testing/debugfs-dwc-pcie | 70 ++++++++ > .../controller/dwc/pcie-designware-debugfs.c | 165 +++++++++++++++++- > 2 files changed, 233 insertions(+), 2 deletions(-) > > diff --git a/Documentation/ABI/testing/debugfs-dwc-pcie b/Documentation/ABI/testing/debugfs-dwc-pcie > index e8ed34e988ef..9eae0ab1dbea 100644 > --- a/Documentation/ABI/testing/debugfs-dwc-pcie > +++ b/Documentation/ABI/testing/debugfs-dwc-pcie > @@ -11,3 +11,73 @@ Contact: Shradha Todi > Description: (RW) Write the lane number to be checked as valid or invalid. Read > will return the status of PIPE RXVALID signal of the selected lane. > The default selected lane is Lane0. > + > +What: /sys/kernel/debug/dwc_pcie_/rasdes_err_inj/ > +Date: Feburary 2025 > +Contact: Shradha Todi > +Description: rasdes_err_inj is the directory which can be used to inject errors in the > + system. The possible errors that can be injected are: > + > + 1) TLP LCRC error injection TX Path - tx_lcrc > + 2) 16b CRC error injection of ACK/NAK DLLP - b16_crc_dllp > + 3) 16b CRC error injection of Update-FC DLLP - b16_crc_upd_fc > + 4) TLP ECRC error injection TX Path - tx_ecrc > + 5) TLP's FCRC error injection TX Path - fcrc_tlp > + 6) Parity error of TSOS - parity_tsos > + 7) Parity error on SKPOS - parity_skpos > + 8) LCRC error injection RX Path - rx_lcrc > + 9) ECRC error injection RX Path - rx_ecrc > + 10) TLPs SEQ# error - tlp_err_seq > + 11) DLLPS ACK/NAK SEQ# error - ack_nak_dllp_seq > + 12) ACK/NAK DLLPs transmission block - ack_nak_dllp > + 13) UpdateFC DLLPs transmission block - upd_fc_dllp > + 14) Always transmission for NAK DLLP - nak_dllp > + 15) Invert SYNC header - inv_sync_hdr_sym > + 16) COM/PAD TS1 order set - com_pad_ts1 > + 17) COM/PAD TS2 order set - com_pad_ts2 > + 18) COM/FTS FTS order set - com_fts > + 19) COM/IDL E-idle order set - com_idl > + 20) END/EDB symbol - end_edb > + 21) STP/SDP symbol - stp_sdp > + 22) COM/SKP SKP order set - com_skp > + 23) Posted TLP Header credit value control - posted_tlp_hdr > + 24) Non-Posted TLP Header credit value control - non_post_tlp_hdr > + 25) Completion TLP Header credit value control - cmpl_tlp_hdr > + 26) Posted TLP Data credit value control - posted_tlp_data > + 27) Non-Posted TLP Data credit value control - non_post_tlp_data > + 28) Completion TLP Data credit value control - cmpl_tlp_data > + 29) Generates duplicate TLPs - duplicate_dllp > + 30) Generates Nullified TLPs - nullified_tlp > + > + Each of the possible errors are WO attributes. Write to the attribute will > + prepare controller to inject the respective error in the next transmission > + of data. Parameter required to write will change in the following ways: > + > + i) Errors 9) - 10) are sequence errors. The write command for these will be > + > + echo > /sys/kernel/debug/dwc_pcie_/rasdes_err_inj/ > + > + > + Number of errors to be injected > + > + The difference to add or subtract from natural sequence number to > + generate sequence error. Range (-4095 : 4095) > + > + ii) Errors 23) - 28) are credit value error insertions. Write command: > + > + echo > /sys/kernel/debug/dwc_pcie_/rasdes_err_inj/ > + > + > + Number of errors to be injected > + > + The difference to add or subtract from UpdateFC credit value. > + Range (-4095 : 4095) > + > + Target VC number > + > + iii) All other errors. Write command: > + > + echo > /sys/kernel/debug/dwc_pcie_/rasdes_err_inj/ > + > + > + Number of errors to be injected > diff --git a/drivers/pci/controller/dwc/pcie-designware-debugfs.c b/drivers/pci/controller/dwc/pcie-designware-debugfs.c > index fe799d36fa7f..dfb0840390d3 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-debugfs.c > +++ b/drivers/pci/controller/dwc/pcie-designware-debugfs.c > @@ -17,6 +17,20 @@ > #define PIPE_DETECT_LANE BIT(17) > #define LANE_SELECT GENMASK(3, 0) > > +#define ERR_INJ0_OFF 0x34 > +#define EINJ_VAL_DIFF GENMASK(28, 16) > +#define EINJ_VC_NUM GENMASK(14, 12) > +#define EINJ_TYPE_SHIFT 8 > +#define EINJ0_TYPE GENMASK(11, 8) > +#define EINJ1_TYPE BIT(8) > +#define EINJ2_TYPE GENMASK(9, 8) > +#define EINJ3_TYPE GENMASK(10, 8) > +#define EINJ4_TYPE GENMASK(10, 8) > +#define EINJ5_TYPE BIT(8) > +#define EINJ_COUNT GENMASK(7, 0) > + > +#define ERR_INJ_ENABLE_REG 0x30 > + > #define DWC_DEBUGFS_BUF_MAX 128 > > struct dwc_pcie_vsec_id { > @@ -55,6 +69,72 @@ struct dwc_pcie_rasdes_info { > struct mutex reg_lock; > }; > > +/** > + * struct dwc_pcie_rasdes_priv - Stores file specific private data information > + * @pci: Reference to the dw_pcie structure > + * @idx: Index to point to specific file related information in array of structs > + * > + * All debugfs files will have this struct as its private data. > + */ > +struct dwc_pcie_rasdes_priv { > + struct dw_pcie *pci; > + int idx; > +}; > + > +/** > + * struct dwc_pcie_err_inj - Store details about each error injection supported by DWC RASDES > + * @name: Name of the error that can be injected > + * @err_inj_group: Group number to which the error belongs to. Value can range from 0 - 5 > + * @err_inj_type: Each group can have multiple types of error > + */ > +struct dwc_pcie_err_inj { > + const char *name; > + u32 err_inj_group; > + u32 err_inj_type; > +}; > + > +static const struct dwc_pcie_err_inj err_inj_list[] = { > + {"tx_lcrc", 0x0, 0x0}, > + {"b16_crc_dllp", 0x0, 0x1}, > + {"b16_crc_upd_fc", 0x0, 0x2}, > + {"tx_ecrc", 0x0, 0x3}, > + {"fcrc_tlp", 0x0, 0x4}, > + {"parity_tsos", 0x0, 0x5}, > + {"parity_skpos", 0x0, 0x6}, > + {"rx_lcrc", 0x0, 0x8}, > + {"rx_ecrc", 0x0, 0xb}, > + {"tlp_err_seq", 0x1, 0x0}, > + {"ack_nak_dllp_seq", 0x1, 0x1}, > + {"ack_nak_dllp", 0x2, 0x0}, > + {"upd_fc_dllp", 0x2, 0x1}, > + {"nak_dllp", 0x2, 0x2}, > + {"inv_sync_hdr_sym", 0x3, 0x0}, > + {"com_pad_ts1", 0x3, 0x1}, > + {"com_pad_ts2", 0x3, 0x2}, > + {"com_fts", 0x3, 0x3}, > + {"com_idl", 0x3, 0x4}, > + {"end_edb", 0x3, 0x5}, > + {"stp_sdp", 0x3, 0x6}, > + {"com_skp", 0x3, 0x7}, > + {"posted_tlp_hdr", 0x4, 0x0}, > + {"non_post_tlp_hdr", 0x4, 0x1}, > + {"cmpl_tlp_hdr", 0x4, 0x2}, > + {"posted_tlp_data", 0x4, 0x4}, > + {"non_post_tlp_data", 0x4, 0x5}, > + {"cmpl_tlp_data", 0x4, 0x6}, > + {"duplicate_dllp", 0x5, 0x0}, > + {"nullified_tlp", 0x5, 0x1}, > +}; > + > +static const u32 err_inj_type_mask[] = { > + EINJ0_TYPE, > + EINJ1_TYPE, > + EINJ2_TYPE, > + EINJ3_TYPE, > + EINJ4_TYPE, > + EINJ5_TYPE, > +}; > + > static ssize_t lane_detect_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) > { > struct dw_pcie *pci = file->private_data; > @@ -115,6 +195,63 @@ static ssize_t rx_valid_write(struct file *file, const char __user *buf, size_t > return lane_detect_write(file, buf, count, ppos); > } > > +static ssize_t err_inj_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) > +{ > + struct dwc_pcie_rasdes_priv *pdata = file->private_data; > + struct dw_pcie *pci = pdata->pci; > + struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > + u32 val, counter, vc_num, err_group, type_mask; > + int val_diff = 0; > + char *kern_buf; > + > + err_group = err_inj_list[pdata->idx].err_inj_group; > + type_mask = err_inj_type_mask[err_group]; > + > + kern_buf = memdup_user_nul(buf, count); > + if (IS_ERR(kern_buf)) > + return PTR_ERR(kern_buf); > + > + if (err_group == 4) { > + val = sscanf(kern_buf, "%u %d %u", &counter, &val_diff, &vc_num); > + if ((val != 3) || (val_diff < -4095 || val_diff > 4095)) { > + kfree(kern_buf); > + return -EINVAL; > + } > + } else if (err_group == 1) { > + val = sscanf(kern_buf, "%u %d", &counter, &val_diff); > + if ((val != 2) || (val_diff < -4095 || val_diff > 4095)) { > + kfree(kern_buf); > + return -EINVAL; > + } > + } else { > + val = kstrtou32(kern_buf, 0, &counter); > + if (val) { > + kfree(kern_buf); > + return val; > + } > + } > + > + val = dw_pcie_readl_dbi(pci, rinfo->ras_cap_offset + ERR_INJ0_OFF + (0x4 * err_group)); > + val &= ~(type_mask | EINJ_COUNT); > + val |= ((err_inj_list[pdata->idx].err_inj_type << EINJ_TYPE_SHIFT) & type_mask); > + val |= FIELD_PREP(EINJ_COUNT, counter); > + > + if (err_group == 1 || err_group == 4) { > + val &= ~(EINJ_VAL_DIFF); > + val |= FIELD_PREP(EINJ_VAL_DIFF, val_diff); > + } > + if (err_group == 4) { > + val &= ~(EINJ_VC_NUM); > + val |= FIELD_PREP(EINJ_VC_NUM, vc_num); > + } > + > + dw_pcie_writel_dbi(pci, rinfo->ras_cap_offset + ERR_INJ0_OFF + (0x4 * err_group), val); > + dw_pcie_writel_dbi(pci, rinfo->ras_cap_offset + ERR_INJ_ENABLE_REG, (0x1 << err_group)); > + > + kfree(kern_buf); > + return count; > +} > + > #define dwc_debugfs_create(name) \ > debugfs_create_file(#name, 0644, rasdes_debug, pci, \ > &dbg_ ## name ## _fops) > @@ -129,6 +266,11 @@ static const struct file_operations dbg_ ## name ## _fops = { \ > DWC_DEBUGFS_FOPS(lane_detect); > DWC_DEBUGFS_FOPS(rx_valid); > > +static const struct file_operations dwc_pcie_err_inj_ops = { > + .open = simple_open, > + .write = err_inj_write, > +}; > + > static void dwc_pcie_rasdes_debugfs_deinit(struct dw_pcie *pci) > { > struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > @@ -138,11 +280,12 @@ static void dwc_pcie_rasdes_debugfs_deinit(struct dw_pcie *pci) > > static int dwc_pcie_rasdes_debugfs_init(struct dw_pcie *pci, struct dentry *dir) > { > - struct dentry *rasdes_debug; > + struct dentry *rasdes_debug, *rasdes_err_inj; > struct dwc_pcie_rasdes_info *rasdes_info; > + struct dwc_pcie_rasdes_priv *priv_tmp; > const struct dwc_pcie_vsec_id *vid; > struct device *dev = pci->dev; > - int ras_cap; > + int ras_cap, i, ret; > > for (vid = dwc_pcie_vsec_ids; vid->vendor_id; vid++) { > ras_cap = dw_pcie_find_vsec_capability(pci, vid->vendor_id, > @@ -161,6 +304,7 @@ static int dwc_pcie_rasdes_debugfs_init(struct dw_pcie *pci, struct dentry *dir) > > /* Create subdirectories for Debug, Error injection, Statistics */ > rasdes_debug = debugfs_create_dir("rasdes_debug", dir); > + rasdes_err_inj = debugfs_create_dir("rasdes_err_inj", dir); > > mutex_init(&rasdes_info->reg_lock); > rasdes_info->ras_cap_offset = ras_cap; > @@ -170,7 +314,24 @@ static int dwc_pcie_rasdes_debugfs_init(struct dw_pcie *pci, struct dentry *dir) > dwc_debugfs_create(lane_detect); > dwc_debugfs_create(rx_valid); > > + /* Create debugfs files for Error injection subdirectory */ > + for (i = 0; i < ARRAY_SIZE(err_inj_list); i++) { > + priv_tmp = devm_kzalloc(dev, sizeof(*priv_tmp), GFP_KERNEL); > + if (!priv_tmp) { > + ret = -ENOMEM; > + goto err_deinit; > + } > + > + priv_tmp->idx = i; > + priv_tmp->pci = pci; > + debugfs_create_file(err_inj_list[i].name, 0200, rasdes_err_inj, priv_tmp, > + &dwc_pcie_err_inj_ops); > + } > return 0; > + > +err_deinit: > + dwc_pcie_rasdes_debugfs_deinit(pci); > + return ret; > } > > void dwc_pcie_debugfs_deinit(struct dw_pcie *pci) > -- > 2.17.1 > -- மணிவண்ணன் சதாசிவம்