Re: [PATCH v2 3/4] drivers: edac: Add EDAC driver support for QCOM SoCs

From: Evan Green
Date: Fri Aug 24 2018 - 16:19:39 EST


On Fri, Aug 24, 2018 at 11:32 AM <vnkgutta@xxxxxxxxxxxxxx> wrote:
>
> On 2018-08-23 16:04, Evan Green wrote:
> > On Fri, Aug 17, 2018 at 5:08 PM Venkata Narendra Kumar Gutta
> > <vnkgutta@xxxxxxxxxxxxxx> wrote:
> >>
> >> From: Channagoud Kadabi <ckadabi@xxxxxxxxxxxxxx>
> >>
> >> Add error reporting driver for Single Bit Errors (SBEs) and Double Bit
> >> Errors (DBEs). As of now, this driver supports erp for Last Level
> >> Cache
> >> Controller (LLCC). This driver takes care of dumping registers and
> >> adding
> >> config options to enable and disable panic when the errors happen in
> >> cache.
> >>
> >> Signed-off-by: Channagoud Kadabi <ckadabi@xxxxxxxxxxxxxx>
> >> Signed-off-by: Venkata Narendra Kumar Gutta <vnkgutta@xxxxxxxxxxxxxx>
> >> Co-developed-by: Venkata Narendra Kumar Gutta
> >> <vnkgutta@xxxxxxxxxxxxxx>
> >> ---
> >> MAINTAINERS | 8 +
> >> drivers/edac/Kconfig | 28 +++
> >> drivers/edac/Makefile | 1 +
> >> drivers/edac/qcom_edac.c | 446
> >> +++++++++++++++++++++++++++++++++++++
> >> include/linux/soc/qcom/llcc-qcom.h | 25 +++
> >> 5 files changed, 508 insertions(+)
> >> create mode 100644 drivers/edac/qcom_edac.c
> >>
> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> index 0a23427..0bff713 100644
> >> --- a/MAINTAINERS
> >> +++ b/MAINTAINERS
> >> @@ -5227,6 +5227,14 @@ L: linux-edac@xxxxxxxxxxxxxxx
> >> S: Maintained
> >> F: drivers/edac/ti_edac.c
> >>
> >> +EDAC-QUALCOMM
> >> +M: Channagoud Kadabi <ckadabi@xxxxxxxxxxxxxx>
> >> +M: Venkata Narendra Kumar Gutta <vnkgutta@xxxxxxxxxxxxxx>
> >> +L: linux-arm-msm@xxxxxxxxxxxxxxx
> >> +L: linux-edac@xxxxxxxxxxxxxxx
> >> +S: Maintained
> >> +F: drivers/edac/qcom_edac.c
> >> +
> >> EDIROL UA-101/UA-1000 DRIVER
> >> M: Clemens Ladisch <clemens@xxxxxxxxxx>
> >> L: alsa-devel@xxxxxxxxxxxxxxxx (moderated for non-subscribers)
> >> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
> >> index 57304b2..da8f150 100644
> >> --- a/drivers/edac/Kconfig
> >> +++ b/drivers/edac/Kconfig
> >> @@ -460,4 +460,32 @@ config EDAC_TI
> >> Support for error detection and correction on the
> >> TI SoCs.
> >>
> >> +config EDAC_QCOM
> >> + tristate "QCOM EDAC Controller"
> >> + depends on EDAC
> >> + help
> >> + Support for error detection and correction on the
> >> + QCOM SoCs.
> >> +
> >> +config EDAC_QCOM_LLCC
> >> + tristate "QCOM EDAC Controller for LLCC Cache"
> >> + depends on EDAC_QCOM && QCOM_LLCC
> >> + help
> >> + Support for error detection and correction on the
> >> + QCOM LLCC cache. Report errors caught by LLCC ECC
> >> + mechanism.
> >> +
> >> + For debugging issues having to do with stability and overall
> >> system
> >> + health, you should probably say 'Y' here.
> >> +
> >> +config EDAC_QCOM_LLCC_PANIC_ON_UE
> >> + bool "Panic on uncorrectable errors - qcom llcc"
> >> + depends on EDAC_QCOM_LLCC
> >> + help
> >> + Forcibly cause a kernel panic if an uncorrectable error (UE)
> >> is
> >> + detected. This can reduce debugging times on hardware which
> >> may be
> >> + operating at voltages or frequencies outside normal
> >> specification.
> >> +
> >> + For production builds, you should probably say 'N' here.
> >> +
> >> endif # EDAC
> >> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
> >> index 02b43a7..716096d 100644
> >> --- a/drivers/edac/Makefile
> >> +++ b/drivers/edac/Makefile
> >> @@ -77,3 +77,4 @@ obj-$(CONFIG_EDAC_ALTERA) +=
> >> altera_edac.o
> >> obj-$(CONFIG_EDAC_SYNOPSYS) += synopsys_edac.o
> >> obj-$(CONFIG_EDAC_XGENE) += xgene_edac.o
> >> obj-$(CONFIG_EDAC_TI) += ti_edac.o
> >> +obj-$(CONFIG_EDAC_QCOM) += qcom_edac.o
> >> diff --git a/drivers/edac/qcom_edac.c b/drivers/edac/qcom_edac.c
> >> new file mode 100644
> >> index 0000000..9a8c670
> >> --- /dev/null
> >> +++ b/drivers/edac/qcom_edac.c
> >> @@ -0,0 +1,446 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
> >> + */
> >> +
> >> +#include <linux/edac.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/kernel.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/regmap.h>
> >> +#include <linux/smp.h>
> >> +#include <linux/soc/qcom/llcc-qcom.h>
> >> +
> >> +#include "edac_mc.h"
> >> +#include "edac_device.h"
> >> +
> >> +#ifdef CONFIG_EDAC_QCOM_LLCC_PANIC_ON_UE
> >> +#define LLCC_ERP_PANIC_ON_UE 1
> >> +#else
> >> +#define LLCC_ERP_PANIC_ON_UE 0
> >> +#endif
> >> +
> >> +#define EDAC_LLCC "qcom_llcc"
> >> +
> >> +#define TRP_SYN_REG_CNT 6
> >> +
> >> +#define DRP_SYN_REG_CNT 8
> >> +
> >> +#define LLCC_COMMON_STATUS0 0x0003000C
> >> +#define LLCC_LB_CNT_MASK GENMASK(31, 28)
> >> +#define LLCC_LB_CNT_SHIFT 28
> >> +
> >> +/* single & Double Bit syndrome register offsets */
> >
> > Strange capitalization going on here.
> I'll fix this.
>
> >
> >> +#define TRP_ECC_SB_ERR_SYN0 0x0002304C
> >> +#define TRP_ECC_DB_ERR_SYN0 0x00020370
> >> +#define DRP_ECC_SB_ERR_SYN0 0x0004204C
> >> +#define DRP_ECC_DB_ERR_SYN0 0x00042070
> >
> > I think the convention is to use lowercase hex everywhere.
>
> I didn't get you. Do you mean, the Macros should be in lower case or the
> comments?

I mean 0x0002304C should be 0x0002304c.

>
> >
> >> +
> >> +/* Error register offsets */
> >> +#define TRP_ECC_ERROR_STATUS1 0x00020348
> >> +#define TRP_ECC_ERROR_STATUS0 0x00020344
> >> +#define DRP_ECC_ERROR_STATUS1 0x00042048
> >> +#define DRP_ECC_ERROR_STATUS0 0x00042044
> >> +
> >> +/* TRP, DRP interrupt register offsets */
> >> +#define DRP_INTERRUPT_STATUS 0x00041000
> >> +#define TRP_INTERRUPT_0_STATUS 0x00020480
> >> +#define DRP_INTERRUPT_CLEAR 0x00041008
> >> +#define DRP_ECC_ERROR_CNTR_CLEAR 0x00040004
> >> +#define TRP_INTERRUPT_0_CLEAR 0x00020484
> >> +#define TRP_ECC_ERROR_CNTR_CLEAR 0x00020440
> >> +
> >> +/* Mask and shift macros */
> >> +#define ECC_DB_ERR_COUNT_MASK GENMASK(4, 0)
> >> +#define ECC_DB_ERR_WAYS_MASK GENMASK(31, 16)
> >> +#define ECC_DB_ERR_WAYS_SHIFT BIT(4)
> >> +
> >> +#define ECC_SB_ERR_COUNT_MASK GENMASK(23, 16)
> >> +#define ECC_SB_ERR_COUNT_SHIFT BIT(4)
> >> +#define ECC_SB_ERR_WAYS_MASK GENMASK(15, 0)
> >> +
> >> +#define SB_ECC_ERROR BIT(0)
> >> +#define DB_ECC_ERROR BIT(1)
> >> +
> >> +#define DRP_TRP_INT_CLEAR GENMASK(1, 0)
> >> +#define DRP_TRP_CNT_CLEAR GENMASK(1, 0)
> >> +
> >> +/* Config registers offsets*/
> >> +#define DRP_ECC_ERROR_CFG 0x00040000
> >> +
> >> +/* TRP, DRP interrupt register offsets */
> >> +#define CMN_INTERRUPT_0_ENABLE 0x0003001C
> >> +#define CMN_INTERRUPT_2_ENABLE 0x0003003C
> >> +#define TRP_INTERRUPT_0_ENABLE 0x00020488
> >> +#define DRP_INTERRUPT_ENABLE 0x0004100C
> >> +
> >> +#define SB_ERROR_THRESHOLD 0x1
> >> +#define SB_ERROR_THRESHOLD_SHIFT 24
> >> +#define SB_DB_TRP_INTERRUPT_ENABLE 0x3
> >> +#define TRP0_INTERRUPT_ENABLE 0x1
> >> +#define DRP0_INTERRUPT_ENABLE BIT(6)
> >> +#define SB_DB_DRP_INTERRUPT_ENABLE 0x3
> >> +
> >> +enum {
> >> + LLCC_DRAM_CE = 0,
> >> + LLCC_DRAM_UE,
> >> + LLCC_TRAM_CE,
> >> + LLCC_TRAM_UE,
> >> + LLCC_ERR_TYPE_MAX = LLCC_TRAM_UE + 1,
> >
> > This is a nit, or perhaps personal preference, but I prefer to not
> > have initializers for sentinel values, since it's one more thing
> > someone could forget to update when adding new values.
>
> I'll get rid of this, I was using this one to allocate the memory for
> llcc_driv_data->edac_reg, (struct llcc_edac_reg_data).
> But the suggestion was to initialize that one statically.

Sounds good.

>
>
> >
> >> +};
> >> +
> >> +static int qcom_llcc_core_setup(struct regmap *llcc_bcast_regmap)
> >> +{
> >> + u32 sb_err_threshold;
> >> + int ret;
> >> +
> >> + /* Enable TRP in instance 2 of common interrupt enable
> >> register */
> >
> > Can we get a comment explaining what's so special about instance 2?
> > Instances 1 and 3 get no love?
>
> I'll try to elaborate on this.
>
> >
> >> + ret = regmap_update_bits(llcc_bcast_regmap,
> >> CMN_INTERRUPT_2_ENABLE,
> >> + TRP0_INTERRUPT_ENABLE,
> >> + TRP0_INTERRUPT_ENABLE);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Enable ECC interrupts on Tag Ram */
> >> + ret = regmap_update_bits(llcc_bcast_regmap,
> >> TRP_INTERRUPT_0_ENABLE,
> >> + SB_DB_TRP_INTERRUPT_ENABLE,
> >> + SB_DB_TRP_INTERRUPT_ENABLE);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Enable SB error for Data RAM */
> >> + sb_err_threshold = (SB_ERROR_THRESHOLD <<
> >> SB_ERROR_THRESHOLD_SHIFT);
> >> + ret = regmap_write(llcc_bcast_regmap, DRP_ECC_ERROR_CFG,
> >> + sb_err_threshold);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Enable DRP in instance 2 of common interrupt enable
> >> register */
> >> + ret = regmap_update_bits(llcc_bcast_regmap,
> >> CMN_INTERRUPT_2_ENABLE,
> >> + DRP0_INTERRUPT_ENABLE,
> >> + DRP0_INTERRUPT_ENABLE);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Enable ECC interrupts on Data Ram */
> >> + ret = regmap_write(llcc_bcast_regmap, DRP_INTERRUPT_ENABLE,
> >> + SB_DB_DRP_INTERRUPT_ENABLE);
> >> + return ret;
> >> +}
> >> +
> >> +/* Clear the error interrupt and counter registers */
> >> +static int
> >> +qcom_llcc_clear_errors_status(int err_type, struct llcc_drv_data
> >> *drv)
> >
> > Another nit: errors_status is kind of weird. Maybe
> > qcom_llcc_clear_errors or qcom_llcc_clear_error_status?
>
> I'll update the name.
>
> >
> >> +{
> >> + int ret = 0;
> >> +
> >> + switch (err_type) {
> >> + case LLCC_DRAM_CE:
> >> + case LLCC_DRAM_UE:
> >> + /* Clear the interrupt */
> >> + ret = regmap_write(drv->bcast_regmap,
> >> DRP_INTERRUPT_CLEAR,
> >> + DRP_TRP_INT_CLEAR);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Clear the counters */
> >> + ret = regmap_write(drv->bcast_regmap,
> >> DRP_ECC_ERROR_CNTR_CLEAR,
> >> + DRP_TRP_CNT_CLEAR);
> >> + if (ret)
> >> + return ret;
> >> + break;
> >> + case LLCC_TRAM_CE:
> >> + case LLCC_TRAM_UE:
> >> + ret = regmap_write(drv->bcast_regmap,
> >> TRP_INTERRUPT_0_CLEAR,
> >> + DRP_TRP_INT_CLEAR);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = regmap_write(drv->bcast_regmap,
> >> TRP_ECC_ERROR_CNTR_CLEAR,
> >> + DRP_TRP_CNT_CLEAR);
> >> + if (ret)
> >> + return ret;
> >> + break;
> >
> > A default case that errors or complains or both would be nice.
>
> Ok, I had this thought too, but we never run into that scenario,
> that's we don't ever call this function with any other types,
> Had it been an API it makes sense to have a default case.
> The internal functions require them too! I don't know!!
> What do you think?
> As we say, if it's good to have it, I'll add it.

I personally like the default case, I find it to be defensive against
someone adding code later who passes the wrong value or type down.
Others might disagree. It's up to you.