Discussion of kernel support for SATA port multipliers.
config SATA_PMP bool "SATA Port Multiplier support" default y help This option adds support for SATA Port Multipliers (the SATA version of an ethernet hub, or SAS expander).
libata-$(CONFIG_SATA_PMP) += libata-pmp.o
enum { /* various global constants */ ... /* ATA device commands */ ... ATA_CMD_PMP_READ = 0xE4, ATA_CMD_PMP_READ_DMA = 0xE9, ATA_CMD_PMP_WRITE = 0xE8, ATA_CMD_PMP_WRITE_DMA = 0xEB, ...
/* PMP stuff */ SATA_PMP_MAX_PORTS = 15, SATA_PMP_CTRL_PORT = 15, SATA_PMP_GSCR_DWORDS = 128, SATA_PMP_GSCR_PROD_ID = 0, SATA_PMP_GSCR_REV = 1, SATA_PMP_GSCR_PORT_INFO = 2, SATA_PMP_GSCR_ERROR = 32, SATA_PMP_GSCR_ERROR_EN = 33, SATA_PMP_GSCR_FEAT = 64, SATA_PMP_GSCR_FEAT_EN = 96, SATA_PMP_PSCR_STATUS = 0, SATA_PMP_PSCR_ERROR = 1, SATA_PMP_PSCR_CONTROL = 2, SATA_PMP_FEAT_BIST = (1 << 0), SATA_PMP_FEAT_PMREQ = (1 << 1), SATA_PMP_FEAT_DYNSSC = (1 << 2), SATA_PMP_FEAT_NOTIFY = (1 << 3),
#define sata_pmp_gscr_vendor(gscr) ((gscr)[SATA_PMP_GSCR_PROD_ID] & 0xffff) #define sata_pmp_gscr_devid(gscr) ((gscr)[SATA_PMP_GSCR_PROD_ID] >> 16) #define sata_pmp_gscr_rev(gscr) (((gscr)[SATA_PMP_GSCR_REV] >> 8) & 0xff) #define sata_pmp_gscr_ports(gscr) ((gscr)[SATA_PMP_GSCR_PORT_INFO] & 0xf)
enum { /* various global constants */ ... ATA_DEV_UNKNOWN = 0, /* unknown device */ ATA_DEV_ATA = 1, /* ATA device */ ATA_DEV_ATA_UNSUP = 2, /* ATA device (unsupported) */ ATA_DEV_ATAPI = 3, /* ATAPI device */ ATA_DEV_ATAPI_UNSUP = 4, /* ATAPI device (unsupported) */ ATA_DEV_PMP = 5, /* SATA port multiplier */ ATA_DEV_PMP_UNSUP = 6, /* SATA port multiplier (unsupported) */ ATA_DEV_SEMB = 7, /* SEMB */ ATA_DEV_SEMB_UNSUP = 8, /* SEMB (unsupported) */ ATA_DEV_ZAC = 9, /* ZAC device */ ATA_DEV_ZAC_UNSUP = 10, /* ZAC device (unsupported) */ ATA_DEV_NONE = 11, /* no device */ ...
/* struct ata_port flags */ ... ATA_FLAG_PMP = (1 << 19), /* controller supports PMP */ ...
struct ata_port_operations { ... void (*pmp_attach)(struct ata_port *ap); void (*pmp_detach)(struct ata_port *ap); ...
#ifdef CONFIG_SATA_PMP static inline bool sata_pmp_supported(struct ata_port *ap) { return ap->flags & ATA_FLAG_PMP; } static inline bool sata_pmp_attached(struct ata_port *ap) { return ap->nr_pmp_links != 0; } static inline bool ata_is_host_link(const struct ata_link *link) { return link == &link->ap->link || link == link->ap->slave_link; } #else /* CONFIG_SATA_PMP */ static inline bool sata_pmp_supported(struct ata_port *ap) { return false; } static inline bool sata_pmp_attached(struct ata_port *ap) { return false; } static inline bool ata_is_host_link(const struct ata_link *link) { return 1; } #endif /* CONFIG_SATA_PMP */
ata_device
-> ata_link
:
struct ata_device { struct ata_link *link; unsigned int devno; /* 0 or 1 */ unsigned int horkage; /* List of broken features */ unsigned long flags; /* ATA_DFLAG_xxx */ struct scsi_device *sdev; /* attached SCSI device */ void *private_data; #ifdef CONFIG_ATA_ACPI union acpi_object *gtf_cache; unsigned int gtf_filter; #endif #ifdef CONFIG_SATA_ZPODD void *zpodd; #endif struct device tdev; /* n_sector is CLEAR_BEGIN, read comment above CLEAR_BEGIN */ u64 n_sectors; /* size of device, if ATA */ u64 n_native_sectors; /* native size, if ATA */ unsigned int class; /* ATA_DEV_xxx */ ... union { u16 id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */ u32 gscr[SATA_PMP_GSCR_DWORDS]; /* PMP GSCR block */ } ____cacheline_aligned;
class
should be DEV_ATA_PMP
.
ata_link
-> ata_port
:
struct ata_link { struct ata_port *ap; int pmp; /* port multiplier port # */ ... struct ata_device device[ATA_MAX_DEVICES];
struct ata_port { struct Scsi_Host *scsi_host; /* our co-allocated scsi host */ struct ata_port_operations *ops; spinlock_t *lock; /* Flags owned by the EH context. Only EH should touch these once the port is active */ unsigned long flags; /* ATA_FLAG_xxx */ ... struct ata_link link; /* host default link */ struct ata_link *slave_link; /* see ata_slave_link_init() */ int nr_pmp_links; /* nr of available PMP links */ struct ata_link *pmp_link; /* array of PMP links */ ... struct ata_host *host; struct device *dev; ...
static int ata_eh_revalidate_and_attach(struct ata_link *link, struct ata_device **r_failed_dev) { struct ata_port *ap = link->ap; struct ata_eh_context *ehc = &link->eh_context; struct ata_device *dev; ... ata_for_each_dev(dev, link, ALL_REVERSE) { ... dev->class = ehc->classes[dev->devno]; if (dev->class == ATA_DEV_PMP) rc = sata_pmp_attach(dev); else ...