RE: [PATCH 4/7] ARM: at91: enable the L2 Cache controller

["Yang, Wenyou" <Wenyou.Yang@atmel.com>]

Hi Alexandre,

> -----Original Message-----
> From: Alexandre Belloni [mailto:alexandre.belloni@free-electrons.com]
> Sent: Tuesday, January 27, 2015 6:37 AM
> To: Yang, Wenyou
> Cc: Ferre, Nicolas; linux@arm.linux.org.uk; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; sylvain.rochet@finsecur.com; peda@axentia.se;
> Vilchez, Patrice
> Subject: Re: [PATCH 4/7] ARM: at91: enable the L2 Cache controller
> 
> Hi Wenyou,
> 
> This patch is not necessary, the only thing missing is the prefetch configuration
> and I will submit the correct DT snippet for 3.21.
I will drop this patch.

> 
> On 26/01/2015 at 18:07:16 +0800, Wenyou Yang wrote :
> > Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> > ---
> >  arch/arm/mach-at91/board-dt-sama5.c |   53
> +++++++++++++++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >
> > diff --git a/arch/arm/mach-at91/board-dt-sama5.c
> > b/arch/arm/mach-at91/board-dt-sama5.c
> > index 86cffcd..ed6db28 100644
> > --- a/arch/arm/mach-at91/board-dt-sama5.c
> > +++ b/arch/arm/mach-at91/board-dt-sama5.c
> > @@ -17,17 +17,70 @@
> >  #include <linux/of_platform.h>
> >  #include <linux/phy.h>
> >  #include <linux/clk-provider.h>
> > +#include <linux/of_address.h>
> >
> >  #include <asm/setup.h>
> >  #include <asm/irq.h>
> >  #include <asm/mach/arch.h>
> >  #include <asm/mach/map.h>
> >  #include <asm/mach/irq.h>
> > +#include <asm/hardware/cache-l2x0.h>
> >
> >  #include "generic.h"
> >
> > +void __iomem *at91_l2cc_base;
> > +EXPORT_SYMBOL_GPL(at91_l2cc_base);
> > +
> > +#ifdef CONFIG_CACHE_L2X0
> > +static void __init at91_init_l2cache(void) {
> > +	struct device_node *np;
> > +	u32 reg;
> > +
> > +	np = of_find_compatible_node(NULL, NULL, "arm,pl310-cache");
> > +	if (!np)
> > +		return;
> > +
> > +	at91_l2cc_base = of_iomap(np, 0);
> > +	if (!at91_l2cc_base)
> > +		panic("unable to map l2cc cpu registers\n");
> > +
> > +	of_node_put(np);
> > +
> > +	/* Disable cache if it hasn't been done yet */
> > +	if (readl_relaxed(at91_l2cc_base + L2X0_CTRL) & L2X0_CTRL_EN)
> > +		writel_relaxed(~L2X0_CTRL_EN, at91_l2cc_base + L2X0_CTRL);
> > +
> > +	/* Prefetch Control */
> > +	reg = readl_relaxed(at91_l2cc_base + L310_PREFETCH_CTRL);
> > +	reg &= ~L310_PREFETCH_CTRL_OFFSET_MASK;
> > +	reg |= 0x01;
> > +	reg |= L310_PREFETCH_CTRL_DBL_LINEFILL_INCR;
> > +	reg |= L310_PREFETCH_CTRL_PREFETCH_DROP;
> > +	reg |= L310_PREFETCH_CTRL_DATA_PREFETCH;
> > +	reg |= L310_PREFETCH_CTRL_INSTR_PREFETCH;
> > +	reg |= L310_PREFETCH_CTRL_DBL_LINEFILL;
> > +	writel_relaxed(reg, at91_l2cc_base + L310_PREFETCH_CTRL);
> > +
> > +	/* Power Control */
> > +	reg = readl_relaxed(at91_l2cc_base + L310_POWER_CTRL);
> > +	reg |= L310_STNDBY_MODE_EN;
> > +	reg |= L310_DYNAMIC_CLK_GATING_EN;
> > +	writel_relaxed(reg, at91_l2cc_base + L310_POWER_CTRL);
> > +
> > +	/* Disable interrupts */
> > +	writel_relaxed(0x00, at91_l2cc_base + L2X0_INTR_MASK);
> > +	writel_relaxed(0x01ff, at91_l2cc_base + L2X0_INTR_CLEAR);
> > +	l2x0_of_init(0, ~0UL);
> > +}
> > +#else
> > +static inline void at91_init_l2cache(void) {} #endif
> > +
> >  static void __init sama5_dt_device_init(void)  {
> > +	at91_init_l2cache();
> > +
> >  	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> >  	at91_sam9x5_pm_init();
> >  }
> > --
> > 1.7.9.5
> >
> 
> --
> Alexandre Belloni, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com


Best Regards,
Wenyou Yang