Re: [PATCH 1/2] memory/mediatek: Add an interface to get current DDR data rate

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On Thu, 2024-12-12 at 11:46 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Il 12/12/24 09:59, Crystal Guo ha scritto:
> > Add MediaTek DRAMC driver to provide an interface that can
> > obtain current DDR data rate.
> > 
> > Signed-off-by: Crystal Guo <crystal.guo@xxxxxxxxxxxx>
> > ---
> >   drivers/memory/Kconfig                 |   1 +
> >   drivers/memory/Makefile                |   1 +
> >   drivers/memory/mediatek/Kconfig        |  21 ++
> >   drivers/memory/mediatek/Makefile       |   2 +
> >   drivers/memory/mediatek/mtk-dramc.c    | 325
> > +++++++++++++++++++++++++
> >   include/linux/soc/mediatek/mtk-dramc.h |  41 ++++
> >   6 files changed, 391 insertions(+)
> >   create mode 100644 drivers/memory/mediatek/Kconfig
> >   create mode 100644 drivers/memory/mediatek/Makefile
> >   create mode 100644 drivers/memory/mediatek/mtk-dramc.c
> >   create mode 100644 include/linux/soc/mediatek/mtk-dramc.h
> > 
> > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> > index c82d8d8a16ea..b1698549ff81 100644
> > --- a/drivers/memory/Kconfig
> > +++ b/drivers/memory/Kconfig
> > @@ -227,5 +227,6 @@ config STM32_FMC2_EBI
> > 
> >   source "drivers/memory/samsung/Kconfig"
> >   source "drivers/memory/tegra/Kconfig"
> > +source "drivers/memory/mediatek/Kconfig"
> > 
> >   endif
> > diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> > index d2e6ca9abbe0..cf1091449d2e 100644
> > --- a/drivers/memory/Makefile
> > +++ b/drivers/memory/Makefile
> > @@ -27,6 +27,7 @@ obj-$(CONFIG_STM32_FMC2_EBI)        += stm32-
> > fmc2-ebi.o
> > 
> >   obj-$(CONFIG_SAMSUNG_MC)    += samsung/
> >   obj-$(CONFIG_TEGRA_MC)              += tegra/
> > +obj-$(CONFIG_HAVE_MTK_MC)    += mediatek/
> >   obj-$(CONFIG_TI_EMIF_SRAM)  += ti-emif-sram.o
> >   obj-$(CONFIG_FPGA_DFL_EMIF) += dfl-emif.o
> > 
> > diff --git a/drivers/memory/mediatek/Kconfig
> > b/drivers/memory/mediatek/Kconfig
> > new file mode 100644
> > index 000000000000..00764cdb157e
> > --- /dev/null
> > +++ b/drivers/memory/mediatek/Kconfig
> > @@ -0,0 +1,21 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +config HAVE_MTK_MC
> > +     bool "MediaTek Memory Controller support"
> > +     help
> > +       This option allows to enable MediaTek memory controller
> > drivers,
> > +       which may include controllers for DRAM or others.
> > +       Select Y here if you need support for MediaTek memory
> > controller.
> > +       If you don't need, select N.
> > +
> > +if HAVE_MTK_MC
> > +
> > +config MTK_DRAMC
> > +     tristate "MediaTek DRAMC driver"
> > +     depends on HAVE_MTK_MC
> > +     help
> > +       This option selects the MediaTek DRAMC driver, which
> > provides
> > +       an interface for reporting the current data rate of DRAM.
> > +       Select Y here if you need support for the MediaTek DRAMC
> > driver.
> > +       If you don't need, select N.
> > +
> > +endif
> > diff --git a/drivers/memory/mediatek/Makefile
> > b/drivers/memory/mediatek/Makefile
> > new file mode 100644
> > index 000000000000..a1395fc55b41
> > --- /dev/null
> > +++ b/drivers/memory/mediatek/Makefile
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +obj-$(CONFIG_MTK_DRAMC)              += mtk-dramc.o
> > diff --git a/drivers/memory/mediatek/mtk-dramc.c
> > b/drivers/memory/mediatek/mtk-dramc.c
> > new file mode 100644
> > index 000000000000..9c2c8e187a4a
> > --- /dev/null
> > +++ b/drivers/memory/mediatek/mtk-dramc.c
> > @@ -0,0 +1,325 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2024 MediaTek Inc.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/printk.h>
> > +#include <linux/io.h>
> > +#include <linux/soc/mediatek/mtk-dramc.h>
> > +
> > +static struct platform_device *dramc_pdev;
> > +static struct platform_driver dramc_drv;
> 
> You don't need these globals.
> 
> > +
> > +static int fmeter_init(struct platform_device *pdev,
> > +                    struct fmeter_dev_t *fmeter_dev_ptr, unsigned
> > int fmeter_version)
> > +{
> > +     struct device_node *dramc_node = pdev->dev.of_node;
> > +     int ret;
> > +
> > +     ret = of_property_read_u32(dramc_node,
> > +                                "crystal-freq", &(fmeter_dev_ptr-
> > >crystal_freq));
> > +     ret |= of_property_read_u32(dramc_node,
> > +                                 "shu-of", &(fmeter_dev_ptr-
> > >shu_of));
> 
> ret |= x doesn't make sense.
> 
> ret = ...
> if (ret)
>         return ret;
> 
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "shu-lv", (unsigned int
> > *)&(fmeter_dev_ptr->shu_lv), 3);
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "pll-id", (unsigned int
> > *)&(fmeter_dev_ptr->pll_id), 3);
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "sdmpcw", (unsigned int
> > *)(fmeter_dev_ptr->sdmpcw), 6);
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "posdiv", (unsigned int
> > *)(fmeter_dev_ptr->posdiv), 6);
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "fbksel", (unsigned int
> > *)(fmeter_dev_ptr->fbksel), 6);
> > +     ret |= of_property_read_u32_array(dramc_node,
> > +                                       "dqsopen", (unsigned int
> > *)(fmeter_dev_ptr->dqsopen), 6);
> > +     if (fmeter_version == 1) {
> > +             fmeter_dev_ptr->version = 1;
> > +             ret |= of_property_read_u32_array(dramc_node,
> > +                     "async-ca", (unsigned int *)(fmeter_dev_ptr-
> > >async_ca), 6);
> > +             ret |= of_property_read_u32_array(dramc_node,
> > +                     "dq-ser-mode", (unsigned int
> > *)(fmeter_dev_ptr->dq_ser_mode), 6);
> > +     }
> > +     return ret;
> > +}
> > +
> > +static ssize_t dram_data_rate_show(struct device_driver *driver,
> > char *buf)
> > +{
> > +     return snprintf(buf, PAGE_SIZE, "DRAM data rate = %d\n",
> > +             mtk_dramc_get_data_rate());
> > +}
> > +
> > +static DRIVER_ATTR_RO(dram_data_rate);> +
> > +static int dramc_probe(struct platform_device *pdev)
> > +{
> > +     struct device_node *dramc_node = pdev->dev.of_node;
> > +     struct dramc_dev_t *dramc_dev_ptr;
> > +     unsigned int fmeter_version;
> > +     struct resource *res;
> > +     unsigned int i, size;
> > +     int ret;
> > +
> > +     pr_info("%s: module probe.\n", __func__);
> 
> This pr_info makes no sense. Please remove.
> 
> > +     dramc_pdev = pdev;
> > +     dramc_dev_ptr = devm_kmalloc(&pdev->dev,
> > +                                  sizeof(struct dramc_dev_t),
> > GFP_KERNEL);
> > +
> > +     if (!dramc_dev_ptr)
> > +             return -ENOMEM;
> > +
> > +     ret = of_property_read_u32(dramc_node,
> > +                                "support-ch-cnt", &dramc_dev_ptr-
> > >support_ch_cnt);
> > +     if (ret) {
> > +             pr_info("%s: get support_ch_cnt fail\n", __func__);
> 
> that's an error, and you want dev_err_probe().
> 
> > +             return -EINVAL;
> > +     }
> > +
> > +     dramc_dev_ptr->sleep_base = of_iomap(dramc_node,
> > +                                          dramc_dev_ptr-
> > >support_ch_cnt * 4);
> > +     if (IS_ERR(dramc_dev_ptr->sleep_base)) {
> > +             pr_info("%s: unable to map sleep base\n", __func__);
> 
> same, here and everywhere else
> 
> > +             return -EINVAL;
> > +     }
> > +
> > +     size = sizeof(phys_addr_t) * dramc_dev_ptr->support_ch_cnt;
> > +     dramc_dev_ptr->dramc_chn_base_ao = devm_kmalloc(&pdev->dev,
> > +                                                     size,
> > GFP_KERNEL);
> > +     if (!(dramc_dev_ptr->dramc_chn_base_ao))
> > +             return -ENOMEM;
> > +     dramc_dev_ptr->dramc_chn_base_nao = devm_kmalloc(&pdev->dev,
> > +                                                      size,
> > GFP_KERNEL);
> > +     if (!(dramc_dev_ptr->dramc_chn_base_nao))
> > +             return -ENOMEM;
> > +     dramc_dev_ptr->ddrphy_chn_base_ao = devm_kmalloc(&pdev->dev,
> > +                                                      size,
> > GFP_KERNEL);
> > +     if (!(dramc_dev_ptr->ddrphy_chn_base_ao))
> > +             return -ENOMEM;
> > +     dramc_dev_ptr->ddrphy_chn_base_nao = devm_kmalloc(&pdev->dev,
> > +                                                       size,
> > GFP_KERNEL);
> > +     if (!(dramc_dev_ptr->ddrphy_chn_base_nao))
> > +             return -ENOMEM;
> > +
> > +     for (i = 0; i < dramc_dev_ptr->support_ch_cnt; i++) {
> > +             res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> > +             dramc_dev_ptr->dramc_chn_base_ao[i] =
> > +                     devm_ioremap_resource(&pdev->dev, res);
> > +             if (IS_ERR(dramc_dev_ptr->dramc_chn_base_ao[i])) {
> > +                     pr_info("%s: unable to map ch%d DRAMC AO
> > base\n",
> > +                             __func__, i);
> > +                     return -EINVAL;
> > +             }
> > +
> > +             res = platform_get_resource(pdev, IORESOURCE_MEM,
> > +                                         i + dramc_dev_ptr-
> > >support_ch_cnt);
> > +             dramc_dev_ptr->dramc_chn_base_nao[i] =
> > +                     devm_ioremap_resource(&pdev->dev, res);
> > +             if (IS_ERR(dramc_dev_ptr->dramc_chn_base_nao[i])) {
> > +                     pr_info("%s: unable to map ch%d DRAMC NAO
> > base\n",
> > +                             __func__, i);
> > +                     return -EINVAL;
> > +             }
> > +
> > +             res = platform_get_resource(pdev, IORESOURCE_MEM,
> > +                                         i + dramc_dev_ptr-
> > >support_ch_cnt * 2);
> > +             dramc_dev_ptr->ddrphy_chn_base_ao[i] =
> > +                     devm_ioremap_resource(&pdev->dev, res);
> > +             if (IS_ERR(dramc_dev_ptr->ddrphy_chn_base_ao[i])) {
> > +                     pr_info("%s: unable to map ch%d DDRPHY AO
> > base\n",
> > +                             __func__, i);
> > +                     return -EINVAL;
> > +             }
> > +
> > +             res = platform_get_resource(pdev, IORESOURCE_MEM,
> > +                                         i + dramc_dev_ptr-
> > >support_ch_cnt * 3);
> > +             dramc_dev_ptr->ddrphy_chn_base_nao[i] =
> > +                     devm_ioremap_resource(&pdev->dev, res);
> > +             if (IS_ERR(dramc_dev_ptr->ddrphy_chn_base_nao[i])) {
> > +                     pr_info("%s: unable to map ch%d DDRPHY NAO
> > base\n",
> > +                             __func__, i);
> > +                     return -EINVAL;
> > +             }
> > +     }
> > +
> > +     ret = of_property_read_u32(dramc_node, "fmeter-version",
> > &fmeter_version);
> 
> This is something for platform data, not devicetree.
> 
> > +     if (ret) {
> > +             pr_info("%s: get fmeter_version fail\n", __func__);
> > +             return -EINVAL;
> > +     }
> > +     pr_info("%s: fmeter_version(%d)\n", __func__,
> > fmeter_version);
> > +
> > +     if (fmeter_version == 1) {
> > +             dramc_dev_ptr->fmeter_dev_ptr = devm_kmalloc(&pdev-
> > >dev,
> > +                                                          sizeof(s
> > truct fmeter_dev_t),
> > +                                                          GFP_KERN
> > EL);
> > +             if (!(dramc_dev_ptr->fmeter_dev_ptr)) {
> > +                     pr_info("%s: memory  alloc fail\n",
> > __func__);
> > +                     return -ENOMEM;
> > +             }
> > +             ret = fmeter_init(pdev, dramc_dev_ptr-
> > >fmeter_dev_ptr, fmeter_version);
> > +             if (ret) {
> > +                     pr_info("%s: fmeter_init fail\n", __func__);
> > +                     return -EINVAL;
> > +             }
> > +     } else {
> > +             dramc_dev_ptr->fmeter_dev_ptr = NULL;
> > +     }
> > +     ret = driver_create_file(pdev->dev.driver,
> > &driver_attr_dram_data_rate);
> > +     if (ret) {
> > +             pr_info("%s: fail to create dram_data_rate sysfs\n",
> > __func__);
> > +             return ret;
> > +     }
> > +
> > +     platform_set_drvdata(pdev, dramc_dev_ptr);
> > +     pr_info("%s: DRAM data rate = %d\n", __func__,
> > +             mtk_dramc_get_data_rate());
> > +
> > +     return ret;
> > +}
> > +
> > +static unsigned int fmeter_v1(struct dramc_dev_t *dramc_dev_ptr)
> > +{
> > +     struct fmeter_dev_t *fmeter_dev_ptr =
> > +             (struct fmeter_dev_t *)dramc_dev_ptr->fmeter_dev_ptr;
> > +     unsigned int shu_lv_val;
> > +     unsigned int pll_id_val;
> > +     unsigned int sdmpcw_val;
> > +     unsigned int posdiv_val;
> > +     unsigned int ckdiv4_val;
> > +     unsigned int offset;
> > +     unsigned int vco_freq;
> > +     unsigned int fbksel;
> > +     unsigned int dqsopen;
> > +     unsigned int async_ca;
> > +     unsigned int dq_ser_mode;
> > +
> > +     shu_lv_val = (readl(dramc_dev_ptr->ddrphy_chn_base_ao[0] +
> > +             fmeter_dev_ptr->shu_lv.offset) &
> > +             fmeter_dev_ptr->shu_lv.mask) >>
> > +             fmeter_dev_ptr->shu_lv.shift;
> > +
> > +     pll_id_val = (readl(dramc_dev_ptr->ddrphy_chn_base_ao[0] +
> > +             fmeter_dev_ptr->pll_id.offset) &
> > +             fmeter_dev_ptr->pll_id.mask) >>
> > +             fmeter_dev_ptr->pll_id.shift;
> > +
> > +     offset = fmeter_dev_ptr->sdmpcw[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     sdmpcw_val = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->sdmpcw[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->sdmpcw[pll_id_val].shift;
> > +
> > +     offset = fmeter_dev_ptr->posdiv[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     posdiv_val = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->posdiv[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->posdiv[pll_id_val].shift;
> > +
> > +     offset = fmeter_dev_ptr->fbksel[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     fbksel = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->fbksel[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->fbksel[pll_id_val].shift;
> > +
> > +     offset = fmeter_dev_ptr->dqsopen[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     dqsopen = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->dqsopen[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->dqsopen[pll_id_val].shift;
> > +
> > +     offset = fmeter_dev_ptr->async_ca[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     async_ca = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->async_ca[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->async_ca[pll_id_val].shift;
> > +
> > +     offset = fmeter_dev_ptr->dq_ser_mode[pll_id_val].offset +
> > +             fmeter_dev_ptr->shu_of * shu_lv_val;
> > +     dq_ser_mode = (readl(dramc_dev_ptr->ddrphy_chn_base_nao[0] +
> > offset) &
> > +             fmeter_dev_ptr->dq_ser_mode[pll_id_val].mask) >>
> > +             fmeter_dev_ptr->dq_ser_mode[pll_id_val].shift;
> > +     ckdiv4_val = (dq_ser_mode == 1); // 1: DIV4, 2: DIV8, 3:
> > DIV16
> > +
> > +     posdiv_val &= ~(0x4);
> > +
> > +     vco_freq = ((fmeter_dev_ptr->crystal_freq) *
> > +             (sdmpcw_val >> 7)) >> posdiv_val >> 1 >> ckdiv4_val
> > +             << fbksel;
> 
> That vco_freq calculation is seriously unreadable :\
> 
> > +
> > +     if ((dqsopen == 1) && (async_ca == 1))
> > +             vco_freq >>= 1;
> > +
> > +     return vco_freq;
> > +}
> > +
> > +/*
> > + * mtk_dramc_get_data_rate - calculate DRAM data rate
> > + *
> > + * Returns DRAM data rate (MB/s)
> > + */
> > +unsigned int mtk_dramc_get_data_rate(void)
> > +{
> > +     struct dramc_dev_t *dramc_dev_ptr;
> > +     struct fmeter_dev_t *fmeter_dev_ptr;
> > +
> > +     if (!dramc_pdev)
> > +             return 0;
> > +
> > +     dramc_dev_ptr =
> > +             (struct dramc_dev_t
> > *)platform_get_drvdata(dramc_pdev);
> > +
> > +     fmeter_dev_ptr = (struct fmeter_dev_t *)dramc_dev_ptr-
> > >fmeter_dev_ptr;
> > +     if (!fmeter_dev_ptr)
> > +             return 0;
> > +
> > +     if (fmeter_dev_ptr->version == 1)
> > +             return fmeter_v1(dramc_dev_ptr);
> > +     return 0;
> > +}
> > +EXPORT_SYMBOL(mtk_dramc_get_data_rate);
> 
> Not sure about mtk_dramc_get_data_rate().
> 
> Please show an example of how you're actually using it in the
> external driver,
> as there are many ways to expose this value.
> 
> > +
> > +static int dramc_remove(struct platform_device *pdev)
> > +{
> > +     dramc_pdev = NULL;
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct of_device_id dramc_of_ids[] = {
> > +     {.compatible = "mediatek,common-dramc",},
> 
> { .compatible = "mediatek,something" },
> { /* sentinel */ }
> 
> > +     {}
> > +};
> > +
> > +static struct platform_driver dramc_drv = {
> > +     .probe = dramc_probe,
> > +     .remove = dramc_remove,
> > +     .driver = {
> > +             .name = "dramc_drv",
> > +             .owner = THIS_MODULE,
> > +             .of_match_table = dramc_of_ids,
> > +     },
> > +};
> 
> module_platform_driver(...)
> 
> > +
> > +static int __init dramc_drv_init(void)
> 
> ...so that function is not needed.
> 
> > +{
> > +     int ret;
> > +
> > +     ret = platform_driver_register(&dramc_drv);
> > +     if (ret) {
> > +             pr_info("%s: init fail, ret 0x%x\n", __func__, ret);
> > +             return ret;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +module_init(dramc_drv_init);
> > +
> > +MODULE_AUTHOR("Mediatek Corporation");
> 
> MODULE_AUTHOR("Author Name <your.email@xxxxxxxxxxxx>");
> 
> > +MODULE_DESCRIPTION("MediaTek DRAMC Driver");
> 
> MODULE_DESCRIPTION("MediaTek DRAM Controller driver");
> 
> 
> 
> ...and I have a hunch that this series will need many versions before
> the code
> quality bar reaches a nice level...
> 
> Cheers,
> Angelo

Thanks for your review.
Following your suggestion, the v2 patch:
https://patchwork.kernel.org/patch/13964208 has been pushed.

Thanks
Crystal
> 
> > +MODULE_LICENSE("GPL");




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