Re: [PATCH v2 12/13] qcom: llcc/edac: Fix the base address used for accessing LLCC banks

Krzysztof Kozlowski
2022-12-13T16:37:55Z

On 12/12/2022 13:33, Manivannan Sadhasivam wrote:
> The Qualcomm LLCC/EDAC drivers were using a fixed register stride for
> accessing the (Control and Status Registers) CSRs of each LLCC bank.
> This stride only works for some SoCs like SDM845 for which driver
> support was initially added.
>
> But the later SoCs use different register stride that vary between the
> banks with holes in-between. So it is not possible to use a single register
> stride for accessing the CSRs of each bank. By doing so could result in a
> crash.
>
> For fixing this issue, let's obtain the base address of each LLCC bank from
> devicetree and get rid of the fixed stride. This also means, we no longer
> need to rely on reg-names property and get the base addresses using index.
>
> First index is LLCC bank 0 and last index is LLCC broadcast. If the SoC
> supports more than one bank, then those needs to be defined in devicetree
> for index from 1..N-1.
>
> Cc: <stable@vger.kernel.org> # 4.20
> Fixes: a3134fb09e0b ("drivers: soc: Add LLCC driver")
> Fixes: 27450653f1db ("drivers: edac: Add EDAC driver support for QCOM SoCs")

Your previous patches in the series had incorrect CC-stable/Fixes tags,
thus I have doubts also here.

Can you confirm, that this patch alone (alone! Without DTS patches) when
backported to v4.20, still works perfectly fine for sdm845?

> Reported-by: Parikshit Pareek <quic_ppareek@quicinc.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
> drivers/edac/qcom_edac.c | 14 +++---
> drivers/soc/qcom/llcc-qcom.c | 72 +++++++++++++++++-------------
> include/linux/soc/qcom/llcc-qcom.h | 6 +--
> 3 files changed, 48 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/edac/qcom_edac.c b/drivers/edac/qcom_edac.c
> index 97a27e42dd61..5be93577fc03 100644
> --- a/drivers/edac/qcom_edac.c
> +++ b/drivers/edac/qcom_edac.c
> @@ -213,7 +213,7 @@ dump_syn_reg_values(struct llcc_drv_data *drv, u32 bank, int err_type)
>
> for (i = 0; i < reg_data.reg_cnt; i++) {
> synd_reg = reg_data.synd_reg + (i * 4);
> - ret = regmap_read(drv->regmap, drv->offsets[bank] + synd_reg,
> + ret = regmap_read(drv->regmaps[bank], synd_reg,
> &synd_val);
> if (ret)
> goto clear;
> @@ -222,8 +222,7 @@ dump_syn_reg_values(struct llcc_drv_data *drv, u32 bank, int err_type)
> reg_data.name, i, synd_val);
> }
>
> - ret = regmap_read(drv->regmap,
> - drv->offsets[bank] + reg_data.count_status_reg,
> + ret = regmap_read(drv->regmaps[bank], reg_data.count_status_reg,
> &err_cnt);
> if (ret)
> goto clear;
> @@ -233,8 +232,7 @@ dump_syn_reg_values(struct llcc_drv_data *drv, u32 bank, int err_type)
> edac_printk(KERN_CRIT, EDAC_LLCC, "%s: Error count: 0x%4x\n",
> reg_data.name, err_cnt);
>
> - ret = regmap_read(drv->regmap,
> - drv->offsets[bank] + reg_data.ways_status_reg,
> + ret = regmap_read(drv->regmaps[bank], reg_data.ways_status_reg,
> &err_ways);
> if (ret)
> goto clear;
> @@ -296,8 +294,7 @@ llcc_ecc_irq_handler(int irq, void *edev_ctl)
>
> /* Iterate over the banks and look for Tag RAM or Data RAM errors */
> for (i = 0; i < drv->num_banks; i++) {
> - ret = regmap_read(drv->regmap,
> - drv->offsets[i] + DRP_INTERRUPT_STATUS,
> + ret = regmap_read(drv->regmaps[i], DRP_INTERRUPT_STATUS,
> &drp_error);
>
> if (!ret && (drp_error & SB_ECC_ERROR)) {
> @@ -312,8 +309,7 @@ llcc_ecc_irq_handler(int irq, void *edev_ctl)
> if (!ret)
> irq_rc = IRQ_HANDLED;
>
> - ret = regmap_read(drv->regmap,
> - drv->offsets[i] + TRP_INTERRUPT_0_STATUS,
> + ret = regmap_read(drv->regmaps[i], TRP_INTERRUPT_0_STATUS,
> &trp_error);
>
> if (!ret && (trp_error & SB_ECC_ERROR)) {
> diff --git a/drivers/soc/qcom/llcc-qcom.c b/drivers/soc/qcom/llcc-qcom.c
> index 23ce2f78c4ed..a29f22dad7fa 100644
> --- a/drivers/soc/qcom/llcc-qcom.c
> +++ b/drivers/soc/qcom/llcc-qcom.c
> @@ -62,8 +62,6 @@
> #define LLCC_TRP_WRSC_CACHEABLE_EN 0x21f2c
> #define LLCC_TRP_ALGO_CFG8 0x21f30
>
> -#define BANK_OFFSET_STRIDE 0x80000
> -
> #define LLCC_VERSION_2_0_0_0 0x02000000
> #define LLCC_VERSION_2_1_0_0 0x02010000
> #define LLCC_VERSION_4_1_0_0 0x04010000
> @@ -898,8 +896,8 @@ static int qcom_llcc_remove(struct platform_device *pdev)
> return 0;
> }
>
> -static struct regmap *qcom_llcc_init_mmio(struct platform_device *pdev,
> - const char *name)
> +static struct regmap *qcom_llcc_init_mmio(struct platform_device *pdev, u8 index,
> + const char *name)
> {
> void __iomem *base;
> struct regmap_config llcc_regmap_config = {
> @@ -909,7 +907,7 @@ static struct regmap *qcom_llcc_init_mmio(struct platform_device *pdev,
> .fast_io = true,
> };
>
> - base = devm_platform_ioremap_resource_byname(pdev, name);
> + base = devm_platform_ioremap_resource(pdev, index);
> if (IS_ERR(base))
> return ERR_CAST(base);
>
> @@ -927,6 +925,7 @@ static int qcom_llcc_probe(struct platform_device *pdev)
> const struct llcc_slice_config *llcc_cfg;
> u32 sz;
> u32 version;
> + struct regmap *regmap;
>
> drv_data = devm_kzalloc(dev, sizeof(*drv_data), GFP_KERNEL);
> if (!drv_data) {
> @@ -934,21 +933,51 @@ static int qcom_llcc_probe(struct platform_device *pdev)
> goto err;
> }
>
> - drv_data->regmap = qcom_llcc_init_mmio(pdev, "llcc_base");
> - if (IS_ERR(drv_data->regmap)) {
> - ret = PTR_ERR(drv_data->regmap);
> + /* Initialize the first LLCC bank regmap */
> + regmap = qcom_llcc_init_mmio(pdev, i, "llcc0_base");

What is the value of "i" here? Looks like not initialized in my next.

> + if (IS_ERR(regmap)) {
> + ret = PTR_ERR(regmap);
> goto err;
> }
>
> - drv_data->bcast_regmap =
> - qcom_llcc_init_mmio(pdev, "llcc_broadcast_base");
> + cfg = of_device_get_match_data(&pdev->dev);
> +
> + ret = regmap_read(regmap, cfg->reg_offset[LLCC_COMMON_STATUS0], &num_banks);
> + if (ret)
> + goto err;
> +
> + num_banks &= LLCC_LB_CNT_MASK;
> + num_banks >>= LLCC_LB_CNT_SHIFT;
> + drv_data->num_banks = num_banks;
> +
> + drv_data->regmaps = devm_kcalloc(dev, num_banks, sizeof(*drv_data->regmaps), GFP_KERNEL);
> + if (!drv_data->regmaps) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + drv_data->regmaps[0] = regmap;
> +
> + /* Initialize rest of LLCC bank regmaps */
> + for (i = 1; i < num_banks; i++) {
> + char *base = kasprintf(GFP_KERNEL, "llcc%d_base", i);
> +
> + drv_data->regmaps[i] = qcom_llcc_init_mmio(pdev, i, base);
> + if (IS_ERR(drv_data->regmaps[i])) {
> + ret = PTR_ERR(drv_data->regmaps[i]);
> + kfree(base);
> + goto err;

This looks like the ABI break so:
1. Existing users are broken,
2. It cannot be backported.

> + }
> +
> + kfree(base);
> + }
> +

Best regards,
Krzysztof