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https://github.com/edk2-porting/linux-next.git
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6aa8b04975
u32* volatile cyclone_timer means volatile auto pointer to u32, which is clearly not what had been intended (we never even take the address of that variable, let alone pass it to something that could change it behind our back). u32 volatile * is what the authors apparently wanted to say, but in reality we don't need that qualifier there at all - it's (properly) only passed to iomem helpers which takes care of that stuff just fine. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
129 lines
3.1 KiB
C
129 lines
3.1 KiB
C
#include <linux/module.h>
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#include <linux/smp.h>
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#include <linux/time.h>
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#include <linux/errno.h>
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#include <linux/timex.h>
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#include <linux/clocksource.h>
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#include <asm/io.h>
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/* IBM Summit (EXA) Cyclone counter code*/
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#define CYCLONE_CBAR_ADDR 0xFEB00CD0
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#define CYCLONE_PMCC_OFFSET 0x51A0
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#define CYCLONE_MPMC_OFFSET 0x51D0
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#define CYCLONE_MPCS_OFFSET 0x51A8
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#define CYCLONE_TIMER_FREQ 100000000
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int use_cyclone;
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void __init cyclone_setup(void)
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{
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use_cyclone = 1;
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}
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static void __iomem *cyclone_mc;
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static cycle_t read_cyclone(void)
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{
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return (cycle_t)readq((void __iomem *)cyclone_mc);
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}
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static struct clocksource clocksource_cyclone = {
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.name = "cyclone",
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.rating = 300,
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.read = read_cyclone,
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.mask = (1LL << 40) - 1,
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.mult = 0, /*to be caluclated*/
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.shift = 16,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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int __init init_cyclone_clock(void)
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{
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u64 __iomem *reg;
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u64 base; /* saved cyclone base address */
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u64 offset; /* offset from pageaddr to cyclone_timer register */
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int i;
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u32 __iomem *cyclone_timer; /* Cyclone MPMC0 register */
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if (!use_cyclone)
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return 0;
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printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
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/* find base address */
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offset = (CYCLONE_CBAR_ADDR);
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reg = ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
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" register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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base = readq(reg);
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if(!base){
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printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
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" value.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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iounmap(reg);
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/* setup PMCC */
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offset = (base + CYCLONE_PMCC_OFFSET);
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reg = ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
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" register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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writel(0x00000001,reg);
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iounmap(reg);
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/* setup MPCS */
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offset = (base + CYCLONE_MPCS_OFFSET);
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reg = ioremap_nocache(offset, sizeof(u64));
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if(!reg){
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printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
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" register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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writel(0x00000001,reg);
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iounmap(reg);
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/* map in cyclone_timer */
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offset = (base + CYCLONE_MPMC_OFFSET);
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cyclone_timer = ioremap_nocache(offset, sizeof(u32));
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if(!cyclone_timer){
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printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
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" register.\n");
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use_cyclone = 0;
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return -ENODEV;
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}
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/*quick test to make sure its ticking*/
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for(i=0; i<3; i++){
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u32 old = readl(cyclone_timer);
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int stall = 100;
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while(stall--) barrier();
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if(readl(cyclone_timer) == old){
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printk(KERN_ERR "Summit chipset: Counter not counting!"
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" DISABLED\n");
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iounmap(cyclone_timer);
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cyclone_timer = NULL;
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use_cyclone = 0;
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return -ENODEV;
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}
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}
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/* initialize last tick */
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cyclone_mc = cyclone_timer;
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clocksource_cyclone.fsys_mmio = cyclone_timer;
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clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
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clocksource_cyclone.shift);
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clocksource_register(&clocksource_cyclone);
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return 0;
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}
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__initcall(init_cyclone_clock);
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