Re: [PATCH 2/3] sdhci: sparx5: Add Sparx5 SoC eMMC driver

From: Lars Povlsen
Date: Mon May 18 2020 - 04:59:32 EST


Adrian Hunter writes:

> On 13/05/20 4:31 pm, Lars Povlsen wrote:
>> This adds the eMMC driver for the Sparx5 SoC. It is based upon the
>> designware IP, but requires some extra initialization and quirks.
>>
>> Reviewed-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
>> Signed-off-by: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
>> ---
>> drivers/mmc/host/Kconfig | 13 ++
>> drivers/mmc/host/Makefile | 1 +
>> drivers/mmc/host/sdhci-of-sparx5.c | 348 +++++++++++++++++++++++++++++
>> 3 files changed, 362 insertions(+)
>> create mode 100644 drivers/mmc/host/sdhci-of-sparx5.c
>>
>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>> index 462b5352fea75..1e8396d09df75 100644
>> --- a/drivers/mmc/host/Kconfig
>> +++ b/drivers/mmc/host/Kconfig
>> @@ -213,6 +213,19 @@ config MMC_SDHCI_OF_DWCMSHC
>> If you have a controller with this interface, say Y or M here.
>> If unsure, say N.
>>
>> +config MMC_SDHCI_OF_SPARX5
>> + tristate "SDHCI OF support for the MCHP Sparx5 SoC"
>> + depends on MMC_SDHCI_PLTFM
>> + depends on ARCH_SPARX5
>> + select MMC_SDHCI_IO_ACCESSORS
>> + help
>> + This selects the Secure Digital Host Controller Interface (SDHCI)
>> + found in the MCHP Sparx5 SoC.
>> +
>> + If you have a Sparx5 SoC with this interface, say Y or M here.
>> +
>> + If unsure, say N.
>> +
>> config MMC_SDHCI_CADENCE
>> tristate "SDHCI support for the Cadence SD/SDIO/eMMC controller"
>> depends on MMC_SDHCI_PLTFM
>> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
>> index b929ef9412083..9f09b7ffaaa16 100644
>> --- a/drivers/mmc/host/Makefile
>> +++ b/drivers/mmc/host/Makefile
>> @@ -89,6 +89,7 @@ obj-$(CONFIG_MMC_SDHCI_OF_ARASAN) += sdhci-of-arasan.o
>> obj-$(CONFIG_MMC_SDHCI_OF_ASPEED) += sdhci-of-aspeed.o
>> obj-$(CONFIG_MMC_SDHCI_OF_AT91) += sdhci-of-at91.o
>> obj-$(CONFIG_MMC_SDHCI_OF_ESDHC) += sdhci-of-esdhc.o
>> +obj-$(CONFIG_MMC_SDHCI_OF_SPARX5) += sdhci-of-sparx5.o
>> obj-$(CONFIG_MMC_SDHCI_OF_HLWD) += sdhci-of-hlwd.o
>> obj-$(CONFIG_MMC_SDHCI_OF_DWCMSHC) += sdhci-of-dwcmshc.o
>> obj-$(CONFIG_MMC_SDHCI_BCM_KONA) += sdhci-bcm-kona.o
>> diff --git a/drivers/mmc/host/sdhci-of-sparx5.c b/drivers/mmc/host/sdhci-of-sparx5.c
>> new file mode 100644
>> index 0000000000000..8253bf80e175a
>> --- /dev/null
>> +++ b/drivers/mmc/host/sdhci-of-sparx5.c
>> @@ -0,0 +1,348 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * drivers/mmc/host/sdhci-of-sparx5.c
>> + *
>> + * MCHP Sparx5 SoC Secure Digital Host Controller Interface.
>> + *
>> + * Copyright (c) 2019 Microchip Inc.
>> + *
>> + * Author: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
>> + */
>> +
>> +//#define DEBUG
>> +//#define TRACE_REGISTER
>
> No commented out code please.

Yes, that's not relevant any more, I'll remove it.

>
>> +
>> +#include <linux/sizes.h>
>> +#include <linux/delay.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/of_device.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/dma-mapping.h>
>> +
>> +#include "sdhci-pltfm.h"
>> +
>> +#define CPU_REGS_GENERAL_CTRL (0x22 * 4)
>> +#define MSHC_DLY_CC_MASK GENMASK(16, 13)
>> +#define MSHC_DLY_CC_SHIFT 13
>> +#define MSHC_DLY_CC_MAX 15
>> +
>> +#define CPU_REGS_PROC_CTRL (0x2C * 4)
>> +#define ACP_CACHE_FORCE_ENA BIT(4)
>> +#define ACP_AWCACHE BIT(3)
>> +#define ACP_ARCACHE BIT(2)
>> +#define ACP_CACHE_MASK (ACP_CACHE_FORCE_ENA|ACP_AWCACHE|ACP_ARCACHE)
>> +
>> +#define MSHC2_VERSION 0x500 /* Off 0x140, reg 0x0 */
>> +#define MSHC2_TYPE 0x504 /* Off 0x140, reg 0x1 */
>> +#define MSHC2_EMMC_CTRL 0x52c /* Off 0x140, reg 0xB */
>> +#define MSHC2_EMMC_CTRL_EMMC_RST_N BIT(2)
>> +#define MSHC2_EMMC_CTRL_IS_EMMC BIT(0)
>> +
>> +struct sdhci_sparx5_data {
>> + struct sdhci_host *host;
>> + struct regmap *cpu_ctrl;
>> + int delay_clock;
>> + struct device_attribute dev_delay_clock;
>> +};
>> +
>> +#define BOUNDARY_OK(addr, len) \
>> + ((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))
>> +
>> +#if defined(TRACE_REGISTER)
>
> If you want this then add a Kconfig entry for it
>

No, I'll just remove it.

>> +static void sdhci_sparx5_writel(struct sdhci_host *host, u32 val, int reg)
>> +{
>> + pr_debug("$$$ writel(0x%08x, 0x%02x)\n", val, reg);
>> + writel(val, host->ioaddr + reg);
>> +}
>> +
>> +static void sdhci_sparx5_writew(struct sdhci_host *host, u16 val, int reg)
>> +{
>> + pr_debug("$$$ writew(0x%04x, 0x%02x)\n", val, reg);
>> + writew(val, host->ioaddr + reg);
>> +}
>> +
>> +static void sdhci_sparx5_writeb(struct sdhci_host *host, u8 val, int reg)
>> +{
>> + pr_debug("$$$ writeb(0x%02x, 0x%02x)\n", val, reg);
>> + writeb(val, host->ioaddr + reg);
>> +}
>> +#endif
>> +
>> +/*
>> + * If DMA addr spans 128MB boundary, we split the DMA transfer into two
>> + * so that each DMA transfer doesn't exceed the boundary.
>> + */
>> +static void sdhci_sparx5_adma_write_desc(struct sdhci_host *host, void **desc,
>> + dma_addr_t addr, int len,
>> + unsigned int cmd)
>> +{
>> + int tmplen, offset;
>> +
>> + pr_debug("write_desc: cmd %02x: len %d, offset 0x%0llx\n",
>> + cmd, len, addr);
>
> Please prefix all kernel messages by either the mmc or device e.g.
>
> pr_debug("%s: write_desc: cmd %02x: len %d, offset 0x%0llx\n",
> mmc_hostname(host->mmc), cmd, len, addr);

Will do.

>> +
>> + if (likely(!len || BOUNDARY_OK(addr, len))) {
>> + sdhci_adma_write_desc(host, desc, addr, len, cmd);
>> + return;
>> + }
>> +
>> + pr_debug("write_desc: splitting dma len %d, offset 0x%0llx\n",
>> + len, addr);
>> +
>> + offset = addr & (SZ_128M - 1);
>> + tmplen = SZ_128M - offset;
>> + sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);
>> +
>> + addr += tmplen;
>> + len -= tmplen;
>> + sdhci_adma_write_desc(host, desc, addr, len, cmd);
>> +}
>> +
>> +static void sparx5_set_cacheable(struct sdhci_host *host, u32 value)
>> +{
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_sparx5_data *sdhci_sparx5 = sdhci_pltfm_priv(pltfm_host);
>> +
>> + pr_debug("%s: Set Cacheable = 0x%x\n", mmc_hostname(host->mmc), value);
>> +
>> + /* Update ACP caching attributes in HW */
>> + regmap_update_bits(sdhci_sparx5->cpu_ctrl,
>> + CPU_REGS_PROC_CTRL, ACP_CACHE_MASK, value);
>> +}
>> +
>> +static void sparx5_set_delay(struct sdhci_host *host, u8 value)
>> +{
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_sparx5_data *sdhci_sparx5 = sdhci_pltfm_priv(pltfm_host);
>> +
>> + pr_debug("%s: Set DLY_CC = %u\n", mmc_hostname(host->mmc), value);
>> +
>> + /* Update DLY_CC in HW */
>> + regmap_update_bits(sdhci_sparx5->cpu_ctrl,
>> + CPU_REGS_GENERAL_CTRL,
>> + MSHC_DLY_CC_MASK,
>> + (value << MSHC_DLY_CC_SHIFT));
>> +}
>> +
>> +static void sdhci_sparx5_set_emmc(struct sdhci_host *host)
>> +{
>> + if (!mmc_card_is_removable(host->mmc)) {
>> + u8 value;
>> +
>> + value = sdhci_readb(host, MSHC2_EMMC_CTRL);
>> + if (!(value & MSHC2_EMMC_CTRL_IS_EMMC)) {
>> + pr_debug("Get EMMC_CTRL: 0x%08x\n", value);
>> + value |= MSHC2_EMMC_CTRL_IS_EMMC;
>> + pr_debug("Set EMMC_CTRL: 0x%08x\n", value);
>> + sdhci_writeb(host, value, MSHC2_EMMC_CTRL);
>> + }
>> + }
>> +}
>> +
>> +static void sdhci_sparx5_reset_emmc(struct sdhci_host *host)
>> +{
>> + u8 value;
>> +
>> + pr_debug("Toggle EMMC_CTRL.EMMC_RST_N\n");
>> + value = sdhci_readb(host, MSHC2_EMMC_CTRL) &
>> + ~MSHC2_EMMC_CTRL_EMMC_RST_N;
>> + sdhci_writeb(host, value, MSHC2_EMMC_CTRL);
>> + /* For eMMC, minimum is 1us but give it 10us for good measure */
>> + udelay(10);
>> + sdhci_writeb(host, value | MSHC2_EMMC_CTRL_EMMC_RST_N,
>> + MSHC2_EMMC_CTRL);
>> + /* For eMMC, minimum is 200us but give it 300us for good measure */
>> + udelay(300);
>
> usleep_range() is better here
>

Got it.

>> +}
>> +
>> +static void sdhci_sparx5_reset(struct sdhci_host *host, u8 mask)
>> +{
>> + pr_debug("*** RESET: mask %d\n", mask);
>> +
>> + sdhci_reset(host, mask);
>> +
>> + /* Be sure CARD_IS_EMMC stays set */
>> + sdhci_sparx5_set_emmc(host);
>> +}
>> +
>> +static const struct sdhci_ops sdhci_sparx5_ops = {
>> +#if defined(TRACE_REGISTER)
>> + .write_l = sdhci_sparx5_writel,
>> + .write_w = sdhci_sparx5_writew,
>> + .write_b = sdhci_sparx5_writeb,
>> +#endif
>> + .set_clock = sdhci_set_clock,
>> + .set_bus_width = sdhci_set_bus_width,
>> + .set_uhs_signaling = sdhci_set_uhs_signaling,
>> + .get_max_clock = sdhci_pltfm_clk_get_max_clock,
>> + .reset = sdhci_sparx5_reset,
>> + .adma_write_desc = sdhci_sparx5_adma_write_desc,
>> +};
>> +
>> +static const struct sdhci_pltfm_data sdhci_sparx5_pdata = {
>> + .quirks = 0,
>> + .quirks2 = SDHCI_QUIRK2_HOST_NO_CMD23 | /* Card quirk */
>
> If this is a card quirk then it should be in drivers/mmc/core/quirks.h not here.

Yes, its supposedly a card quirk. I'll see to use the card quirks
methods in place.

>
>> + SDHCI_QUIRK2_NO_1_8_V, /* No sdr104, ddr50, etc */
>> + .ops = &sdhci_sparx5_ops,
>> +};
>> +
>> +static ssize_t sparx5_delay_clock_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct sdhci_sparx5_data *sdhci_sparx5;
>> +
>> + sdhci_sparx5 = container_of(attr, struct sdhci_sparx5_data,
>> + dev_delay_clock);
>> + return scnprintf(buf, PAGE_SIZE, "%d\n", sdhci_sparx5->delay_clock);
>> +}
>> +
>> +static ssize_t sparx5_delay_clock_store(struct device *dev,
>> + struct device_attribute *attr,
>> + const char *buf, size_t count)
>> +{
>> + unsigned int delay_clock;
>> + struct sdhci_sparx5_data *sdhci_sparx5;
>> +
>> + sdhci_sparx5 = container_of(attr, struct sdhci_sparx5_data,
>> + dev_delay_clock);
>> +
>> + if (kstrtoint(buf, 10, &delay_clock) ||
>> + delay_clock > MSHC_DLY_CC_MAX) {
>> + dev_err(dev, "sdhci-of-sparx5: wrong parameter format.\n");
>> + return -EINVAL;
>> + }
>> +
>> + sdhci_sparx5->delay_clock = delay_clock;
>> + sparx5_set_delay(sdhci_sparx5->host, sdhci_sparx5->delay_clock);
>> +
>> + return strlen(buf);
>> +}
>> +
>> +int sdhci_sparx5_probe(struct platform_device *pdev)
>> +{
>> + int ret;
>> + const char *syscon = "microchip,sparx5-cpu-syscon";
>> + struct sdhci_host *host;
>> + struct sdhci_pltfm_host *pltfm_host;
>> + struct sdhci_sparx5_data *sdhci_sparx5;
>> + struct device_node *np = pdev->dev.of_node;
>> + u32 value;
>> + u32 extra;
>> +
>> + host = sdhci_pltfm_init(pdev, &sdhci_sparx5_pdata,
>> + sizeof(*sdhci_sparx5));
>> +
>> + if (IS_ERR(host))
>> + return PTR_ERR(host);
>> +
>> + /*
>> + * extra adma table cnt for cross 128M boundary handling.
>> + */
>> + extra = DIV_ROUND_UP_ULL(dma_get_required_mask(&pdev->dev), SZ_128M);
>> + if (extra > SDHCI_MAX_SEGS)
>> + extra = SDHCI_MAX_SEGS;
>> + host->adma_table_cnt += extra;
>> +
>> + pltfm_host = sdhci_priv(host);
>> + sdhci_sparx5 = sdhci_pltfm_priv(pltfm_host);
>> + sdhci_sparx5->host = host;
>> +
>> + pltfm_host->clk = devm_clk_get(&pdev->dev, "core");
>> + if (IS_ERR(pltfm_host->clk)) {
>> + ret = PTR_ERR(pltfm_host->clk);
>> + dev_err(&pdev->dev, "failed to get core clk: %d\n", ret);
>> + goto free_pltfm;
>> + }
>> + ret = clk_prepare_enable(pltfm_host->clk);
>> + if (ret)
>> + goto free_pltfm;
>> +
>> + if (!of_property_read_u32(np, "microchip,clock-delay", &value) &&
>> + value <= MSHC_DLY_CC_MAX)
>> + sdhci_sparx5->delay_clock = value;
>> + else
>> + sdhci_sparx5->delay_clock = -1; /* Autotune */
>> +
>> + /* Sysfs delay_clock interface */
>> + sdhci_sparx5->dev_delay_clock.show = sparx5_delay_clock_show;
>> + sdhci_sparx5->dev_delay_clock.store = sparx5_delay_clock_store;
>> + sysfs_attr_init(&sdhci_sparx5->dev_delay_clock.attr);
>> + sdhci_sparx5->dev_delay_clock.attr.name = "delay_clock";
>> + sdhci_sparx5->dev_delay_clock.attr.mode = 0644;
>> + ret = device_create_file(&pdev->dev, &sdhci_sparx5->dev_delay_clock);
>
> Why is this needed? It seems doubtful that user space knows what value to
> put here if neither the board information nor the driver have that information.

The interface was provided to do tuning with a scope attached. As it is
not a requirement, I'll remove it.

>
>> + if (ret)
>> + dev_err(&pdev->dev, "failure creating '%s' device file",
>> + sdhci_sparx5->dev_delay_clock.attr.name);
>> +
>> + sdhci_get_of_property(pdev);
>> +
>> + ret = mmc_of_parse(host->mmc);
>> + if (ret)
>> + goto err_clk;
>> +
>> + sdhci_sparx5->cpu_ctrl = syscon_regmap_lookup_by_compatible(syscon);
>> + if (IS_ERR(sdhci_sparx5->cpu_ctrl)) {
>> + dev_err(&pdev->dev, "No CPU syscon regmap !\n");
>> + ret = PTR_ERR(sdhci_sparx5->cpu_ctrl);
>> + goto err_clk;
>> + }
>> +
>> + if (sdhci_sparx5->delay_clock >= 0)
>> + sparx5_set_delay(host, sdhci_sparx5->delay_clock);
>> +
>> + if (!mmc_card_is_removable(host->mmc)) {
>> + /* Do a HW reset of eMMC card */
>> + sdhci_sparx5_reset_emmc(host);
>> + /* Update EMMC_CTRL */
>> + sdhci_sparx5_set_emmc(host);
>> + /* If eMMC, disable SD and SDIO */
>> + host->mmc->caps2 |= (MMC_CAP2_NO_SDIO|MMC_CAP2_NO_SD);
>> + }
>> +
>> + /* Enable v4 mode */
>> + //sdhci_enable_v4_mode(host);
>
> No commented out code please.

I'll remove this.

>
>> +
>> + ret = sdhci_add_host(host);
>> + if (ret)
>> + dev_err(&pdev->dev, "sdhci_add_host() failed (%d)\n", ret);
>> +
>> + /* Set AXI bus master to use un-cached access (for DMA) */
>> + if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA) &&
>> + IS_ENABLED(CONFIG_DMA_DECLARE_COHERENT))
>> + sparx5_set_cacheable(host, ACP_CACHE_FORCE_ENA);
>> +
>> + pr_debug("SDHC version: 0x%08x\n", sdhci_readl(host, MSHC2_VERSION));
>> + pr_debug("SDHC type: 0x%08x\n", sdhci_readl(host, MSHC2_TYPE));
>> +
>> + return ret;
>> +
>> +err_clk:
>> + clk_disable_unprepare(pltfm_host->clk);
>> +free_pltfm:
>> + sdhci_pltfm_free(pdev);
>> + return ret;
>> +}
>> +
>> +static const struct of_device_id sdhci_sparx5_of_match[] = {
>> + { .compatible = "microchip,dw-sparx5-sdhci" },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(of, sdhci_sparx5_of_match);
>> +
>> +static struct platform_driver sdhci_sparx5_driver = {
>> + .driver = {
>> + .name = "sdhci-sparx5",
>> + .of_match_table = sdhci_sparx5_of_match,
>> + .pm = &sdhci_pltfm_pmops,
>> + },
>> + .probe = sdhci_sparx5_probe,
>> + .remove = sdhci_pltfm_unregister,
>> +};
>> +
>> +module_platform_driver(sdhci_sparx5_driver);
>> +
>> +MODULE_DESCRIPTION("Sparx5 SDHCI OF driver");
>> +MODULE_AUTHOR("Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.26.2
>>

Thank you very much for your comments, I will make the suggested changes
and submit an new series asap.

--
Lars Povlsen,
Microchip