/* * ALSA driver for ICEnsemble ICE1712 (Envy24) * * AK4524 / AK4528 / AK4529 / AK4355 / AK4381 interface * * Copyright (c) 2000 Jaroslav Kysela * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include #include #include #include #include #include #include #include #include "ice1712.h" MODULE_AUTHOR("Jaroslav Kysela "); MODULE_DESCRIPTION("ICEnsemble ICE17xx <-> AK4xxx AD/DA chip interface"); MODULE_LICENSE("GPL"); static void snd_ice1712_akm4xxx_lock(struct snd_akm4xxx *ak, int chip) { struct snd_ice1712 *ice = ak->private_data[0]; snd_ice1712_save_gpio_status(ice); } static void snd_ice1712_akm4xxx_unlock(struct snd_akm4xxx *ak, int chip) { struct snd_ice1712 *ice = ak->private_data[0]; snd_ice1712_restore_gpio_status(ice); } /* * write AK4xxx register */ static void snd_ice1712_akm4xxx_write(struct snd_akm4xxx *ak, int chip, unsigned char addr, unsigned char data) { unsigned int tmp; int idx; unsigned int addrdata; struct snd_ak4xxx_private *priv = (void *)ak->private_value[0]; struct snd_ice1712 *ice = ak->private_data[0]; if (snd_BUG_ON(chip < 0 || chip >= 4)) return; tmp = snd_ice1712_gpio_read(ice); tmp |= priv->add_flags; tmp &= ~priv->mask_flags; if (priv->cs_mask == priv->cs_addr) { if (priv->cif) { tmp |= priv->cs_mask; /* start without chip select */ } else { tmp &= ~priv->cs_mask; /* chip select low */ snd_ice1712_gpio_write(ice, tmp); udelay(1); } } else { /* doesn't handle cf=1 yet */ tmp &= ~priv->cs_mask; tmp |= priv->cs_addr; snd_ice1712_gpio_write(ice, tmp); udelay(1); } /* build I2C address + data byte */ addrdata = (priv->caddr << 6) | 0x20 | (addr & 0x1f); addrdata = (addrdata << 8) | data; for (idx = 15; idx >= 0; idx--) { /* drop clock */ tmp &= ~priv->clk_mask; snd_ice1712_gpio_write(ice, tmp); udelay(1); /* set data */ if (addrdata & (1 << idx)) tmp |= priv->data_mask; else tmp &= ~priv->data_mask; snd_ice1712_gpio_write(ice, tmp); udelay(1); /* raise clock */ tmp |= priv->clk_mask; snd_ice1712_gpio_write(ice, tmp); udelay(1); } if (priv->cs_mask == priv->cs_addr) { if (priv->cif) { /* assert a cs pulse to trigger */ tmp &= ~priv->cs_mask; snd_ice1712_gpio_write(ice, tmp); udelay(1); } tmp |= priv->cs_mask; /* chip select high to trigger */ } else { tmp &= ~priv->cs_mask; tmp |= priv->cs_none; /* deselect address */ } snd_ice1712_gpio_write(ice, tmp); udelay(1); } /* * initialize the struct snd_akm4xxx record with the template */ int snd_ice1712_akm4xxx_init(struct snd_akm4xxx *ak, const struct snd_akm4xxx *temp, const struct snd_ak4xxx_private *_priv, struct snd_ice1712 *ice) { struct snd_ak4xxx_private *priv; if (_priv != NULL) { priv = kmalloc(sizeof(*priv), GFP_KERNEL); if (priv == NULL) return -ENOMEM; *priv = *_priv; } else { priv = NULL; } *ak = *temp; ak->card = ice->card; ak->private_value[0] = (unsigned long)priv; ak->private_data[0] = ice; if (ak->ops.lock == NULL) ak->ops.lock = snd_ice1712_akm4xxx_lock; if (ak->ops.unlock == NULL) ak->ops.unlock = snd_ice1712_akm4xxx_unlock; if (ak->ops.write == NULL) ak->ops.write = snd_ice1712_akm4xxx_write; snd_akm4xxx_init(ak); return 0; } void snd_ice1712_akm4xxx_free(struct snd_ice1712 *ice) { unsigned int akidx; if (ice->akm == NULL) return; for (akidx = 0; akidx < ice->akm_codecs; akidx++) { struct snd_akm4xxx *ak = &ice->akm[akidx]; kfree((void*)ak->private_value[0]); } kfree(ice->akm); } /* * build AK4xxx controls */ int snd_ice1712_akm4xxx_build_controls(struct snd_ice1712 *ice) { unsigned int akidx; int err; for (akidx = 0; akidx < ice->akm_codecs; akidx++) { struct snd_akm4xxx *ak = &ice->akm[akidx]; err = snd_akm4xxx_build_controls(ak); if (err < 0) return err; } return 0; } static int __init alsa_ice1712_akm4xxx_module_init(void) { return 0; } static void __exit alsa_ice1712_akm4xxx_module_exit(void) { } module_init(alsa_ice1712_akm4xxx_module_init) module_exit(alsa_ice1712_akm4xxx_module_exit) EXPORT_SYMBOL(snd_ice1712_akm4xxx_init); EXPORT_SYMBOL(snd_ice1712_akm4xxx_free); EXPORT_SYMBOL(snd_ice1712_akm4xxx_build_controls); c6b9da46f52122 /drivers/usb parentf466ae66fa6a599f9a53b5f9bafea4b8cfffa7fb (diff)
rcu: Narrow early boot window of illegal synchronous grace periods
The current preemptible RCU implementation goes through three phases during bootup. In the first phase, there is only one CPU that is running with preemption disabled, so that a no-op is a synchronous grace period. In the second mid-boot phase, the scheduler is running, but RCU has not yet gotten its kthreads spawned (and, for expedited grace periods, workqueues are not yet running. During this time, any attempt to do a synchronous grace period will hang the system (or complain bitterly, depending). In the third and final phase, RCU is fully operational and everything works normally. This has been OK for some time, but there has recently been some synchronous grace periods showing up during the second mid-boot phase. This code worked "by accident" for awhile, but started failing as soon as expedited RCU grace periods switched over to workqueues in commit 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue"). Note that the code was buggy even before this commit, as it was subject to failure on real-time systems that forced all expedited grace periods to run as normal grace periods (for example, using the rcu_normal ksysfs parameter). The callchain from the failure case is as follows: early_amd_iommu_init() |-> acpi_put_table(ivrs_base); |-> acpi_tb_put_table(table_desc); |-> acpi_tb_invalidate_table(table_desc); |-> acpi_tb_release_table(...) |-> acpi_os_unmap_memory |-> acpi_os_unmap_iomem |-> acpi_os_map_cleanup |-> synchronize_rcu_expedited The kernel showing this callchain was built with CONFIG_PREEMPT_RCU=y, which caused the code to try using workqueues before they were initialized, which did not go well. This commit therefore reworks RCU to permit synchronous grace periods to proceed during this mid-boot phase. This commit is therefore a fix to a regression introduced in v4.9, and is therefore being put forward post-merge-window in v4.10. This commit sets a flag from the existing rcu_scheduler_starting() function which causes all synchronous grace periods to take the expedited path. The expedited path now checks this flag, using the requesting task to drive the expedited grace period forward during the mid-boot phase. Finally, this flag is updated by a core_initcall() function named rcu_exp_runtime_mode(), which causes the runtime codepaths to be used. Note that this arrangement assumes that tasks are not sent POSIX signals (or anything similar) from the time that the first task is spawned through core_initcall() time. Fixes: 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue") Reported-by: "Zheng, Lv" <lv.zheng@intel.com> Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Stan Kain <stan.kain@gmail.com> Tested-by: Ivan <waffolz@hotmail.com> Tested-by: Emanuel Castelo <emanuel.castelo@gmail.com> Tested-by: Bruno Pesavento <bpesavento@infinito.it> Tested-by: Borislav Petkov <bp@suse.de> Tested-by: Frederic Bezies <fredbezies@gmail.com> Cc: <stable@vger.kernel.org> # 4.9.0-
Diffstat (limited to 'drivers/usb')