On Fri, Jun 23, 2023 at 07:48:05PM +0530, Komal Bajaj wrote:
> Add LLCC support for multi channel DDR configuration
> based on a feature register. Reading DDR channel
> confiuration uses nvmem framework, so select the
> dependency in Kconfig. Without this, there will be
> errors while building the driver with COMPILE_TEST only.
You may drop the last sentence, I don't think it's entirely correct.
>
> Signed-off-by: Komal Bajaj <quic_kbajaj@xxxxxxxxxxx>
> ---
> drivers/soc/qcom/Kconfig | 2 ++
> drivers/soc/qcom/llcc-qcom.c | 33 ++++++++++++++++++++++++++++++---
> 2 files changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index a491718f8064..cc9ad41c63aa 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -64,6 +64,8 @@ config QCOM_LLCC
> tristate "Qualcomm Technologies, Inc. LLCC driver"
> depends on ARCH_QCOM || COMPILE_TEST
> select REGMAP_MMIO
> + select NVMEM
> + select QCOM_SCM
I don't see anything your patch that warrants adding QCOM_SCM here,
is it needed, should it be a separate commit?
> help
> Qualcomm Technologies, Inc. platform specific
> Last Level Cache Controller(LLCC) driver for platforms such as,
> diff --git a/drivers/soc/qcom/llcc-qcom.c b/drivers/soc/qcom/llcc-qcom.c
> index 6cf373da5df9..3c29612da1c5 100644
> --- a/drivers/soc/qcom/llcc-qcom.c
> +++ b/drivers/soc/qcom/llcc-qcom.c
> @@ -12,6 +12,7 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> +#include <linux/nvmem-consumer.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/regmap.h>
> @@ -943,6 +944,19 @@ static int qcom_llcc_cfg_program(struct platform_device *pdev,
> return ret;
> }
>
> +static int qcom_llcc_get_cfg_index(struct platform_device *pdev, u8 *cfg_index)
> +{
> + int ret;
> +
> + ret = nvmem_cell_read_u8(&pdev->dev, "multi-chan-ddr", cfg_index);
> + if (ret == -ENOENT) {
> + *cfg_index = 0;
> + return 0;
> + }
> +
> + return ret;
> +}
> +
> static int qcom_llcc_remove(struct platform_device *pdev)
> {
> /* Set the global pointer to a error code to avoid referencing it */
> @@ -975,11 +989,13 @@ static int qcom_llcc_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> int ret, i;
> struct platform_device *llcc_edac;
> - const struct qcom_llcc_config *cfg;
> + const struct qcom_llcc_config *cfg, *entry;
> const struct llcc_slice_config *llcc_cfg;
> u32 sz;
> + u8 cfg_index;
> u32 version;
> struct regmap *regmap;
> + u32 num_entries = 0;
>
> drv_data = devm_kzalloc(dev, sizeof(*drv_data), GFP_KERNEL);
> if (!drv_data) {
> @@ -1040,8 +1056,19 @@ static int qcom_llcc_probe(struct platform_device *pdev)
>
> drv_data->version = version;
>
> - llcc_cfg = cfg[0]->sct_data;
> - sz = cfg[0]->size;
> + ret = qcom_llcc_get_cfg_index(pdev, &cfg_index);
> + if (ret)
> + goto err;
> +
> + for (entry = cfg; entry->sct_data; entry++, num_entries++)
> + ;
This is still unnecessarily "clever":
"For each valid entry, do nothing, while incrementing num_entries".
How about just writing:
"For each valid entry, increment num_entries"
for (entry = cfg; entry->sct_data; entry++)
num_entries++;
> + if (cfg_index >= num_entries || cfg_index < 0) {
cfg_index is an unsiged number, so it's unlikely to be negative.
Also, "cfg_index" and "num_entries" are values in the same domain, so
keeping their names related is beneficial - i.e. rename num_entries to
num_cfgs.
Regards,
Bjorn
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + llcc_cfg = cfg[cfg_index].sct_data;
> + sz = cfg[cfg_index].size;
>
> for (i = 0; i < sz; i++)
> if (llcc_cfg[i].slice_id > drv_data->max_slices)
> --
> 2.40.1
>
