Messages in this thread | | | Subject | Re: [RFC PATCH 5/5] fsi/scom: Major overhaul | From | Eddie James <> | Date | Thu, 14 Jun 2018 09:12:25 -0500 |
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On 06/13/2018 06:00 PM, Benjamin Herrenschmidt wrote: > On Wed, 2018-06-13 at 09:57 -0500, Eddie James wrote: >> On 06/12/2018 12:19 AM, Benjamin Herrenschmidt wrote: >>> This was too hard to split ... this adds a number of features >>> to the SCOM user interface: >>> >>> - Support for indirect SCOMs >>> >>> - read()/write() interface now handle errors and retries >>> >>> - New ioctl() "raw" interface for use by debuggers >>> >>> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> >>> --- >>> drivers/fsi/fsi-scom.c | 424 ++++++++++++++++++++++++++++++++++++--- >>> include/uapi/linux/fsi.h | 56 ++++++ >>> 2 files changed, 450 insertions(+), 30 deletions(-) >>> create mode 100644 include/uapi/linux/fsi.h >>> >>> diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c >>> index e98573ecdae1..39c74351f1bf 100644 >>> --- a/drivers/fsi/fsi-scom.c >>> +++ b/drivers/fsi/fsi-scom.c >>> @@ -24,6 +24,8 @@ >>> #include <linux/list.h> >>> #include <linux/idr.h> >>> + >>> +static int scom_reset(struct scom_device *scom, void __user *argp) >>> +{ >>> + uint32_t flags, dummy = -1; >>> + int rc = 0; >>> + >>> + if (get_user(flags, (__u32 __user *)argp)) >>> + return -EFAULT; >>> + if (flags & SCOM_RESET_PIB) >>> + rc = fsi_device_write(scom->fsi_dev, SCOM_PIB_RESET_REG, &dummy, >>> + sizeof(uint32_t)); >> I realize this is a user requested flag but I believe the BMC is never >> supposed to issue this type of reset, due to the possibility of breaking >> stuff on the host side. Not sure if it should even be available? > It's for use by cronus or similar low level system debuggers. > > Cheers, > Ben.
Cool, thanks.
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
> >> Otherwise, looks good! >> Thanks, >> Eddie >> >>> + if (!rc && (flags & (SCOM_RESET_PIB | SCOM_RESET_INTF))) >>> + rc = fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy, >>> + sizeof(uint32_t)); >>> + return rc; >>> +} >>> + >>> +static int scom_check(struct scom_device *scom, void __user *argp) >>> +{ >>> + /* Still need to find out how to get "protected" */ >>> + return put_user(SCOM_CHECK_SUPPORTED, (__u32 __user *)argp); >>> +} >>> + >>> +static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg) >>> +{ >>> + struct miscdevice *mdev = file->private_data; >>> + struct scom_device *scom = to_scom_dev(mdev); >>> + void __user *argp = (void __user *)arg; >>> + int rc = -ENOTTY; >>> + >>> + mutex_lock(&scom->lock); >>> + switch(cmd) { >>> + case FSI_SCOM_CHECK: >>> + rc = scom_check(scom, argp); >>> + break; >>> + case FSI_SCOM_READ: >>> + rc = scom_raw_read(scom, argp); >>> + break; >>> + case FSI_SCOM_WRITE: >>> + rc = scom_raw_write(scom, argp); >>> + break; >>> + case FSI_SCOM_RESET: >>> + rc = scom_reset(scom, argp); >>> + break; >>> + } >>> + mutex_unlock(&scom->lock); >>> + return rc; >>> +} >>> + >>> static const struct file_operations scom_fops = { >>> - .owner = THIS_MODULE, >>> - .llseek = scom_llseek, >>> - .read = scom_read, >>> - .write = scom_write, >>> + .owner = THIS_MODULE, >>> + .llseek = scom_llseek, >>> + .read = scom_read, >>> + .write = scom_write, >>> + .unlocked_ioctl = scom_ioctl, >>> }; >>> >>> static int scom_probe(struct device *dev) >>> diff --git a/include/uapi/linux/fsi.h b/include/uapi/linux/fsi.h >>> new file mode 100644 >>> index 000000000000..6008d93f2e48 >>> --- /dev/null >>> +++ b/include/uapi/linux/fsi.h >>> @@ -0,0 +1,56 @@ >>> +#ifndef _UAPI_LINUX_FSI_H >>> +#define _UAPI_LINUX_FSI_H >>> + >>> +#include <linux/ioctl.h> >>> + >>> +/* >>> + * /dev/scom "raw" ioctl interface >>> + * >>> + * The driver supports a high level "read/write" interface which >>> + * handles retries and converts the status to Linux error codes, >>> + * however low level tools an debugger need to access the "raw" >>> + * HW status information and interpret it themselves, so this >>> + * ioctl interface is also provided for their use case. >>> + */ >>> + >>> +/* Structure for SCOM read/write */ >>> +struct scom_access { >>> + __u64 addr; /* SCOM address, supports indirect */ >>> + __u64 data; /* SCOM data (in for write, out for read) */ >>> + __u64 mask; /* Data mask for writes */ >>> + __u32 intf_errors; /* Interface error flags */ >>> +#define SCOM_INTF_ERR_PARITY 0x00000001 /* Parity error */ >>> +#define SCOM_INTF_ERR_PROTECTION 0x00000002 /* Blocked by secure boot */ >>> +#define SCOM_INTF_ERR_ABORT 0x00000004 /* PIB reset during access */ >>> +#define SCOM_INTF_ERR_UNKNOWN 0x80000000 /* Unknown error */ >>> + /* >>> + * Note: Any other bit set in intf_errors need to be considered as an >>> + * error. Future implementations may define new error conditions. The >>> + * pib_status below is only valid if intf_errors is 0. >>> + */ >>> + __u8 pib_status; /* 3-bit PIB status */ >>> +#define SCOM_PIB_SUCCESS 0 /* Access successful */ >>> +#define SCOM_PIB_BLOCKED 1 /* PIB blocked, pls retry */ >>> +#define SCOM_PIB_OFFLINE 2 /* Chiplet offline */ >>> +#define SCOM_PIB_PARTIAL 3 /* Partial good */ >>> +#define SCOM_PIB_BAD_ADDR 4 /* Invalid address */ >>> +#define SCOM_PIB_CLK_ERR 5 /* Clock error */ >>> +#define SCOM_PIB_PARITY_ERR 6 /* Parity error on the PIB bus */ >>> +#define SCOM_PIB_TIMEOUT 7 /* Bus timeout */ >>> + __u8 pad; >>> +}; >>> + >>> +/* Flags for SCOM check */ >>> +#define SCOM_CHECK_SUPPORTED 0x00000001 /* Interface supported */ >>> +#define SCOM_CHECK_PROTECTED 0x00000002 /* Interface blocked by secure boot */ >>> + >>> +/* Flags for SCOM reset */ >>> +#define SCOM_RESET_INTF 0x00000001 /* Reset interface */ >>> +#define SCOM_RESET_PIB 0x00000002 /* Reset PIB */ >>> + >>> +#define FSI_SCOM_CHECK _IOR('s', 0x00, __u32) >>> +#define FSI_SCOM_READ _IOWR('s', 0x01, struct scom_access) >>> +#define FSI_SCOM_WRITE _IOWR('s', 0x02, struct scom_access) >>> +#define FSI_SCOM_RESET _IOW('s', 0x03, __u32) >>> + >>> +#endif /* _UAPI_LINUX_FSI_H */
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