Re: [PATCH V6 3/6] scsi: ufs: qcom: Add multiple frequency support for unipro clk attributes

From: Bjorn Andersson
Date: Fri Sep 01 2023 - 11:40:49 EST

On Fri, Sep 01, 2023 at 05:13:33PM +0530, Nitin Rawat wrote:
> Add Support to configure CORE_CLK_1US_CYCLES, PA_VS_CORE_CLK_40NS_CYCLES
> for multiple unipro clock frequencies. Currently this is handled only for
> only 150Mhz and 75MHz.
>
> Since different qualcomm targets support different unipro frequency, add
> support to handle all other frequencies like 403MHz, 300MHz, 202MHz,
> 150 MHz, 75Mhz, 37.5 MHz.
>

Please flip your commit message around, start with the problem
description (the second paragraph), then the description of what you're
changing.

> Co-developed-by: Naveen Kumar Goud Arepalli <quic_narepall@xxxxxxxxxxx>
> Signed-off-by: Naveen Kumar Goud Arepalli <quic_narepall@xxxxxxxxxxx>
> Signed-off-by: Nitin Rawat <quic_nitirawa@xxxxxxxxxxx>
> ---
> drivers/ufs/host/ufs-qcom.c | 96 ++++++++++++++++++++++++++++---------
> drivers/ufs/host/ufs-qcom.h | 10 ++++
> 2 files changed, 84 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 018e391c276e..e3648e936498 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -94,8 +94,7 @@ static struct ufs_qcom_host *ufs_qcom_hosts[MAX_UFS_QCOM_HOSTS];
>
> static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
> static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> - u32 clk_cycles,
> - u32 clk_40ns_cycles);
> + bool is_max_freq);

Odd indentation here. That said, I doubt that you need the line wrap
now.

>
> static struct ufs_qcom_host *rcdev_to_ufs_host(struct reset_controller_dev *rcd)
> {
> @@ -686,13 +685,14 @@ static int ufs_qcom_link_startup_notify(struct ufs_hba *hba,
> return -EINVAL;
> }
>
> - if (ufs_qcom_cap_qunipro(host))
> - /*
> - * set unipro core clock cycles to 150 & clear clock
> - * divider
> - */
> - err = ufs_qcom_set_core_clk_ctrl(hba,
> - 150, 6);
> + if (ufs_qcom_cap_qunipro(host)) {
> + err = ufs_qcom_set_core_clk_ctrl(hba, true);
> + if (err) {
> + dev_err(hba->dev,
> + "%s cfg core clk ctrl failed\n",
> + __func__);

Please don't build error messages using __func__, describe the actual
error, in English.

> + }
> + }
>
> /*
> * Some UFS devices (and may be host) have issues if LCC is
> @@ -1297,13 +1297,67 @@ static void ufs_qcom_exit(struct ufs_hba *hba)
> phy_exit(host->generic_phy);
> }
> static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> - u32 cycles_in_1us,
> - u32 cycles_in_40ns)
> + bool is_max_freq)

You changed this function prototype in both patch 1 and patch 2, and now
you're changing it again. What if you make this transition in patch 1,
then you only need to change the prototype once.

> {
> struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> + struct list_head *head = &hba->clk_list_head;
> u32 core_clk_ctrl_reg, reg;
> + struct ufs_clk_info *clki;
> + u32 cycles_in_1us, cycles_in_40ns;
> int ret;
>
> + list_for_each_entry(clki, head, list) {
> + if (!IS_ERR_OR_NULL(clki->clk) &&
> + !strcmp(clki->name, "core_clk_unipro")) {
> + if (is_max_freq)
> + cycles_in_1us = clki->max_freq;
> + else
> + cycles_in_1us = clk_get_rate(clki->clk);
> + break;
> + }
> + }
> +
> + if ((cycles_in_1us % (1000 * 1000)) != 0)
> + cycles_in_1us = cycles_in_1us/(1000 * 1000) + 1;
> + else
> + cycles_in_1us = cycles_in_1us/(1000 * 1000);
> +

Iiuc, the following 34 lines only apply to hw_ver >= 4.

> + /*
> + * Generic formulae for cycles_in_40ns = (freq_unipro/25) is not
> + * applicable for all frequencies. For ex: ceil(37.5 MHz/25) will
> + * be 2 and ceil(403 MHZ/25) will be 17 whereas Hardware
> + * specification expect to be 16. Hence use exact hardware spec
> + * mandated value for cycles_in_40ns instead of calculating using
> + * generic formulae.
> + */
> + switch (cycles_in_1us) {
> + case UNIPRO_CORE_CLK_FREQ_403_MHZ:
> + cycles_in_40ns = 16;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_300_MHZ:
> + cycles_in_40ns = 12;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_201_5_MHZ:
> + cycles_in_40ns = 8;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_150_MHZ:
> + cycles_in_40ns = 6;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_100_MHZ:
> + cycles_in_40ns = 4;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_75_MHZ:
> + cycles_in_40ns = 3;
> + break;
> + case UNIPRO_CORE_CLK_FREQ_37_5_MHZ:
> + cycles_in_40ns = 2;
> + break;
> + default:
> + ret = -EINVAL;

5 lines below, you're overwriting this value and moving on as if nothing
happened. Doesn't your compiler complain that you then will use
cycles_in_40ns without first initializing it in this case?

> + dev_err(hba->dev, "UNIPRO clk freq %u MHz not supported\n",
> + cycles_in_1us);
> + }
> +
> ret = ufshcd_dme_get(hba,
> UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> &core_clk_ctrl_reg);
> @@ -1326,7 +1380,7 @@ static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> /* Clear CORE_CLK_DIV_EN */
> core_clk_ctrl_reg &= ~DME_VS_CORE_CLK_CTRL_CORE_CLK_DIV_EN_BIT;

The following 6 changes just corrects the compilation error you
shouldn't have introduced in the previous patch.

>
> - err = ufshcd_dme_set(hba,
> + ret = ufshcd_dme_set(hba,
> UIC_ARG_MIB(DME_VS_CORE_CLK_CTRL),
> core_clk_ctrl_reg);
> /*
> @@ -1334,25 +1388,25 @@ static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba,
> * PA_VS_CORE_CLK_40NS_CYCLES attribute per programmed
> * frequency of unipro core clk of UFS host controller.
> */
> - if (!err && (host->hw_ver.major >= 4)) {
> + if (!ret && (host->hw_ver.major >= 4)) {
> if (cycles_in_40ns > PA_VS_CORE_CLK_40NS_CYCLES_MASK)
> return -EINVAL;
>
> - err = ufshcd_dme_get(hba,
> + ret = ufshcd_dme_get(hba,
> UIC_ARG_MIB(PA_VS_CORE_CLK_40NS_CYCLES),
> &reg);
> - if (err)
> - return err;
> + if (ret)
> + return ret;
>
> reg &= ~PA_VS_CORE_CLK_40NS_CYCLES_MASK;
> reg |= cycles_in_40ns;
>
> - err = ufshcd_dme_set(hba,
> + ret = ufshcd_dme_set(hba,
> UIC_ARG_MIB(PA_VS_CORE_CLK_40NS_CYCLES),
> reg);
> }
>
> - return err;
> + return ret;
> }
>
> static int ufs_qcom_clk_scale_up_pre_change(struct ufs_hba *hba)
> @@ -1368,8 +1422,7 @@ static int ufs_qcom_clk_scale_up_post_change(struct ufs_hba *hba)
> if (!ufs_qcom_cap_qunipro(host))
> return 0;
>
> - /* set unipro core clock cycles to 150 and clear clock divider */
> - return ufs_qcom_set_core_clk_ctrl(hba, 150, 6);
> + return ufs_qcom_set_core_clk_ctrl(hba, true);
> }
>
> static int ufs_qcom_clk_scale_down_pre_change(struct ufs_hba *hba)
> @@ -1404,8 +1457,7 @@ static int ufs_qcom_clk_scale_down_post_change(struct ufs_hba *hba)
> if (!ufs_qcom_cap_qunipro(host))
> return 0;
>
> - /* set unipro core clock cycles to 75 and clear clock divider */
> - return ufs_qcom_set_core_clk_ctrl(hba, 75, 3);
> + return ufs_qcom_set_core_clk_ctrl(hba, false);
> }
>
> static int ufs_qcom_clk_scale_notify(struct ufs_hba *hba,
> diff --git a/drivers/ufs/host/ufs-qcom.h b/drivers/ufs/host/ufs-qcom.h
> index d81bf1a1b77a..bc176ef58e3e 100644
> --- a/drivers/ufs/host/ufs-qcom.h
> +++ b/drivers/ufs/host/ufs-qcom.h
> @@ -9,6 +9,7 @@
> #include <linux/reset.h>
> #include <soc/qcom/ice.h>
> #include <ufs/ufshcd.h>
> +#include <linux/math.h>

Why is math.h needed in this header file now?

Regards,
Bjorn

>
> #define MAX_UFS_QCOM_HOSTS 1
> #define MAX_U32 (~(u32)0)
> @@ -79,6 +80,15 @@ enum {
> UFS_MEM_CQIS_VS = 0x8,
> };
>
> +/* QCOM UFS host controller core clk frequencies */
> +#define UNIPRO_CORE_CLK_FREQ_37_5_MHZ 38
> +#define UNIPRO_CORE_CLK_FREQ_75_MHZ 75
> +#define UNIPRO_CORE_CLK_FREQ_100_MHZ 100
> +#define UNIPRO_CORE_CLK_FREQ_150_MHZ 150
> +#define UNIPRO_CORE_CLK_FREQ_300_MHZ 300
> +#define UNIPRO_CORE_CLK_FREQ_201_5_MHZ 202
> +#define UNIPRO_CORE_CLK_FREQ_403_MHZ 403
> +
> #define UFS_CNTLR_2_x_x_VEN_REGS_OFFSET(x) (0x000 + x)
> #define UFS_CNTLR_3_x_x_VEN_REGS_OFFSET(x) (0x400 + x)
>
> --
> 2.17.1
>