[linux-yocto] [PATCH 1/3] drivers/misc: Axxia MTC Driver Memory Initialization Check

[Dragomir, Daniel]

Adding John Jacques, the proper person to respond on this.

Regards,
Daniel
________________________________________
From: Winkler, Tomas [tomas.winkler at intel.com]
Sent: Monday, August 22, 2016 12:52 PM
To: Dragomir, Daniel; linux-yocto at yoctoproject.org
Subject: RE: [linux-yocto] [PATCH 1/3] drivers/misc: Axxia MTC Driver Memory    Initialization Check

>
> Axxia MTC driver changes:
>  - Memory initialization completion check added
>  - ECC error status clearing added
>
> Signed-off-by: Sreedevi Joshi <sreedevi.joshi at intel.com>
> ---
>  drivers/misc/lsi-mtc.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/drivers/misc/lsi-mtc.c b/drivers/misc/lsi-mtc.c index
> 55c3403..f4fbe6f 100644
> --- a/drivers/misc/lsi-mtc.c
> +++ b/drivers/misc/lsi-mtc.c
> @@ -31,6 +31,7 @@
>  #include <linux/string.h>
>  #include "linux/lsi_mtc_ioctl.h"
>
> +#define MTC_POLL_TIMEOUT (msecs_to_jiffies(1000))
>
>  /*
>     device tree node:
> @@ -4114,6 +4115,8 @@ static long _mtc_config(struct mtc_device *dev,
> struct lsi_mtc_cfg_t *pMTCCfg)
>       struct ncp_axis_mtc_MTC_CONFIG0_REG_ADDR_r_t cfg0 = { 0 };
>       struct ncp_axis_mtc_MTC_CONFIG1_REG_ADDR_r_t cfg1 = { 0 };
>       struct ncp_axis_mtc_MTC_EXECUTE1_REG_ADDR_r_t exec1 = { 0 };
> +     u32     init_reg = { 0 };
> +     unsigned long tmo = 0;
>
>       if ((!pMTCCfg) || (!dev))
>               return -EINVAL;
> @@ -4129,6 +4132,21 @@ static long _mtc_config(struct mtc_device *dev,
> struct lsi_mtc_cfg_t *pMTCCfg)
>       exec1.sw_reset = 1;
>       dev->regs->execute = *((u32 *) &exec1);
>       dev->regs->mem_init = 0x202;
> +     /* wait for the init to complete */
> +     tmo = jiffies + MTC_POLL_TIMEOUT;
> +     do {
> +             init_reg = *(&(dev->regs->mem_init));+

I'm not familiar with this code but I don't think this is the way to read a register , why not using readl(), you are at least missing memory barrier here.

> +             if ((init_reg & 0x101) == 0x101)
> +                     break;
> +     } while (time_before(jiffies, tmo));

This is busy loop, how fast is that going to settle ?

> +
> +     if ((init_reg & 0x101) != 0x101) {
> +             pr_debug("warning: mem_init failed value=0x%x
> (expected:0x101)\n",
> +                            init_reg);
> +     }
> +
> +     /* clear ECC interrupt status */
> +     dev->regs->ecc_int_status = 0xF;
>
>       /* 3. config MTC */
>       cfg0 =
> --
> 2.7.4
>
> --
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