From ac371987a81c61c2efbd6931245cdcaf43baad89 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 7 Apr 2008 22:47:19 +0900 Subject: [PATCH] libata: clear SError after link resume SError used to be cleared in ->postreset. This has small hotplug race condition. If a device is plugged in after reset is complete but postreset hasn't run yet, its hotplug event gets lost when SError is cleared. This patch makes sata_link_resume() clear SError. This kills the race condition and makes a lot of sense as some PMP and host PHYs don't work properly without SError cleared. This change makes sata_pmp_std_{pre|post}_reset()'s unnecessary as they become identical to ata_std counterparts. It also simplifies sata_pmp_hardreset() and ahci_vt8251_hardreset(). Signed-off-by: Tejun Heo --- drivers/ata/ahci.c | 5 --- drivers/ata/libata-core.c | 35 +++++++++------ drivers/ata/libata-pmp.c | 93 +-------------------------------------- include/linux/libata.h | 2 - 4 files changed, 23 insertions(+), 112 deletions(-) diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index 0f553aaa6f7..a69bcca4eb1 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1377,7 +1377,6 @@ static int ahci_vt8251_hardreset(struct ata_link *link, unsigned int *class, unsigned long deadline) { struct ata_port *ap = link->ap; - u32 serror; bool online; int rc; @@ -1388,10 +1387,6 @@ static int ahci_vt8251_hardreset(struct ata_link *link, unsigned int *class, rc = sata_link_hardreset(link, sata_ehc_deb_timing(&link->eh_context), deadline, &online, NULL); - /* vt8251 needs SError cleared for the port to operate */ - ahci_scr_read(ap, SCR_ERROR, &serror); - ahci_scr_write(ap, SCR_ERROR, serror); - ahci_start_engine(ap); DPRINTK("EXIT, rc=%d, class=%u\n", rc, *class); diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index c4fd4afbf34..e00b620f161 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -90,9 +90,9 @@ const struct ata_port_operations sata_port_ops = { const struct ata_port_operations sata_pmp_port_ops = { .inherits = &sata_port_ops, - .pmp_prereset = sata_pmp_std_prereset, + .pmp_prereset = ata_std_prereset, .pmp_hardreset = sata_pmp_std_hardreset, - .pmp_postreset = sata_pmp_std_postreset, + .pmp_postreset = ata_std_postreset, .error_handler = sata_pmp_error_handler, }; @@ -3493,7 +3493,7 @@ int sata_link_debounce(struct ata_link *link, const unsigned long *params, int sata_link_resume(struct ata_link *link, const unsigned long *params, unsigned long deadline) { - u32 scontrol; + u32 scontrol, serror; int rc; if ((rc = sata_scr_read(link, SCR_CONTROL, &scontrol))) @@ -3509,7 +3509,25 @@ int sata_link_resume(struct ata_link *link, const unsigned long *params, */ msleep(200); - return sata_link_debounce(link, params, deadline); + if ((rc = sata_link_debounce(link, params, deadline))) + return rc; + + /* Clear SError. PMP and some host PHYs require this to + * operate and clearing should be done before checking PHY + * online status to avoid race condition (hotplugging between + * link resume and status check). + */ + if (!(rc = sata_scr_read(link, SCR_ERROR, &serror))) + rc = sata_scr_write(link, SCR_ERROR, serror); + if (rc == 0 || rc == -EINVAL) { + unsigned long flags; + + spin_lock_irqsave(link->ap->lock, flags); + link->eh_info.serror = 0; + spin_unlock_irqrestore(link->ap->lock, flags); + rc = 0; + } + return rc; } /** @@ -3701,18 +3719,11 @@ int sata_std_hardreset(struct ata_link *link, unsigned int *class, */ void ata_std_postreset(struct ata_link *link, unsigned int *classes) { - u32 serror; - DPRINTK("ENTER\n"); /* print link status */ sata_print_link_status(link); - /* clear SError */ - if (sata_scr_read(link, SCR_ERROR, &serror) == 0) - sata_scr_write(link, SCR_ERROR, serror); - link->eh_info.serror = 0; - DPRINTK("EXIT\n"); } @@ -6296,9 +6307,7 @@ EXPORT_SYMBOL_GPL(ata_pci_device_resume); #endif /* CONFIG_PCI */ EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch); -EXPORT_SYMBOL_GPL(sata_pmp_std_prereset); EXPORT_SYMBOL_GPL(sata_pmp_std_hardreset); -EXPORT_SYMBOL_GPL(sata_pmp_std_postreset); EXPORT_SYMBOL_GPL(sata_pmp_error_handler); EXPORT_SYMBOL_GPL(__ata_ehi_push_desc); diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c index 7f1a87f01ab..2f8a9577c26 100644 --- a/drivers/ata/libata-pmp.c +++ b/drivers/ata/libata-pmp.c @@ -175,49 +175,6 @@ int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val) return 0; } -/** - * sata_pmp_std_prereset - prepare PMP link for reset - * @link: link to be reset - * @deadline: deadline jiffies for the operation - * - * @link is about to be reset. Initialize it. - * - * LOCKING: - * Kernel thread context (may sleep) - * - * RETURNS: - * 0 on success, -errno otherwise. - */ -int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline) -{ - struct ata_eh_context *ehc = &link->eh_context; - const unsigned long *timing = sata_ehc_deb_timing(ehc); - int rc; - - /* if we're about to do hardreset, nothing more to do */ - if (ehc->i.action & ATA_EH_HARDRESET) - return 0; - - /* resume link */ - rc = sata_link_resume(link, timing, deadline); - if (rc) { - /* phy resume failed */ - ata_link_printk(link, KERN_WARNING, "failed to resume link " - "for reset (errno=%d)\n", rc); - return rc; - } - - /* clear SError bits including .X which blocks the port when set */ - rc = sata_scr_write(link, SCR_ERROR, 0xffffffff); - if (rc) { - ata_link_printk(link, KERN_ERR, - "failed to clear SError (errno=%d)\n", rc); - return rc; - } - - return 0; -} - /** * sata_pmp_std_hardreset - standard hardreset method for PMP link * @link: link to be reset @@ -238,33 +195,13 @@ int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline) int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class, unsigned long deadline) { - const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context); - bool online; u32 tmp; int rc; DPRINTK("ENTER\n"); - /* do hardreset */ - rc = sata_link_hardreset(link, timing, deadline, &online, NULL); - if (rc) { - ata_link_printk(link, KERN_ERR, - "COMRESET failed (errno=%d)\n", rc); - goto out; - } - - /* clear SError bits including .X which blocks the port when set */ - rc = sata_scr_write(link, SCR_ERROR, 0xffffffff); - if (rc) { - ata_link_printk(link, KERN_ERR, "failed to clear SError " - "during hardreset (errno=%d)\n", rc); - goto out; - } + rc = sata_std_hardreset(link, class, deadline); - /* if device is present, follow up with srst to wait for !BSY */ - if (online) - rc = -EAGAIN; - out: /* if SCR isn't accessible, we need to reset the PMP */ if (rc && rc != -EAGAIN && sata_scr_read(link, SCR_STATUS, &tmp)) rc = -ERESTART; @@ -273,34 +210,6 @@ int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class, return rc; } -/** - * ata_std_postreset - standard postreset method for PMP link - * @link: the target ata_link - * @classes: classes of attached devices - * - * This function is invoked after a successful reset. Note that - * the device might have been reset more than once using - * different reset methods before postreset is invoked. - * - * LOCKING: - * Kernel thread context (may sleep) - */ -void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class) -{ - u32 serror; - - DPRINTK("ENTER\n"); - - /* clear SError */ - if (sata_scr_read(link, SCR_ERROR, &serror) == 0) - sata_scr_write(link, SCR_ERROR, serror); - - /* print link status */ - sata_print_link_status(link); - - DPRINTK("EXIT\n"); -} - /** * sata_pmp_read_gscr - read GSCR block of SATA PMP * @dev: PMP device diff --git a/include/linux/libata.h b/include/linux/libata.h index c060cd3cba6..b9188371b12 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -1025,10 +1025,8 @@ static inline int ata_acpi_cbl_80wire(struct ata_port *ap, * PMP - drivers/ata/libata-pmp.c */ extern int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc); -extern int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline); extern int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class, unsigned long deadline); -extern void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class); extern void sata_pmp_error_handler(struct ata_port *ap); /* -- 2.20.1