![Russell King](/assets/img/avatar_default.png)
Consolidating the "pen_release" stuff amongst the various SoC implementations gives credence to having a CPU holding pen for secondary CPUs. However, this is far from the truth. Many SoC implementations cargo-cult copied various bits of the pen release implementation from the initial Realview/Versatile Express implementation without understanding what it was or why it existed. The reason it existed is because these are _development_ platforms, and some board firmware is unable to individually control the startup of secondary CPUs. Moreover, they do not have a way to power down or reset secondary CPUs for hot-unplug. Hence, the pen_release implementation was designed for ARM Ltd's development platforms to provide a working implementation, even though it is very far from what is required. It was decided a while back to reduce the duplication by consolidating the "pen_release" variable, but this only made the situation worse - we have ended up with several implementations that read this variable but do not write it - again, showing the cargo-cult mentality at work, lack of proper review of new code, and in some cases a lack of testing. While it would be preferable to remove pen_release entirely from the kernel, this is not possible without help from the SoC maintainers, which seems to be lacking. However, I want to remove pen_release from arch code to remove the credence that having it gives. This patch removes pen_release from the arch code entirely, adding private per-SoC definitions for it instead, and explicitly stating that write_pen_release() is cargo-cult copied and should not be copied any further. Rename write_pen_release() in a similar fashion as well. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
/*
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* spear machine family generic header file
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*
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* Copyright (C) 2009-2012 ST Microelectronics
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* Rajeev Kumar <rajeev-dlh.kumar@st.com>
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* Viresh Kumar <vireshk@kernel.org>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#ifndef __MACH_GENERIC_H
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#define __MACH_GENERIC_H
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#include <linux/dmaengine.h>
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#include <linux/amba/pl08x.h>
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#include <linux/init.h>
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#include <linux/reboot.h>
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#include <asm/mach/time.h>
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extern volatile int spear_pen_release;
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extern void spear13xx_timer_init(void);
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extern void spear3xx_timer_init(void);
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extern struct pl022_ssp_controller pl022_plat_data;
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extern struct pl08x_platform_data pl080_plat_data;
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void __init spear_setup_of_timer(void);
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void __init spear3xx_clk_init(void __iomem *misc_base,
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void __iomem *soc_config_base);
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void __init spear3xx_map_io(void);
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void __init spear3xx_dt_init_irq(void);
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void __init spear6xx_clk_init(void __iomem *misc_base);
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void __init spear13xx_map_io(void);
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void __init spear13xx_l2x0_init(void);
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void spear_restart(enum reboot_mode, const char *);
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void spear13xx_secondary_startup(void);
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void spear13xx_cpu_die(unsigned int cpu);
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extern const struct smp_operations spear13xx_smp_ops;
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#ifdef CONFIG_MACH_SPEAR1310
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void __init spear1310_clk_init(void __iomem *misc_base, void __iomem *ras_base);
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#else
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static inline void spear1310_clk_init(void __iomem *misc_base, void __iomem *ras_base) {}
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#endif
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#ifdef CONFIG_MACH_SPEAR1340
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void __init spear1340_clk_init(void __iomem *misc_base);
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#else
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static inline void spear1340_clk_init(void __iomem *misc_base) {}
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#endif
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#endif /* __MACH_GENERIC_H */
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