mmc: meson: Add driver for the SD/MMC host found on Amlogic MesonX SoCs

From: Carlo Caione <[email protected]>

Add a driver for the SD/MMC host found on the Amlogic MesonX SoCs. This is an MMC controller which provides an interface between the application processor and various memory cards. It supports the SD specification v2.0 and the eMMC specification v4.41.

This patch adds also the binding documentation.

Signed-off-by Carlo Caione <[email protected]>

---
Changelog:

v2:
* fix typo in commit message
* avoid the bounce buffer (max_segs == 1)

v3:
* simplify meson_mmc_map_dma() and fix memory leak

v4:
* code and documentation cleanup
* removed redundant variables
* removed useless printing
* introduced MMC_CAP2_NO_SDIO
* removed state machine
* better spinlocks management and positioning

---
 .../devicetree/bindings/mmc/meson-mmc.txt          |  29 ++
 drivers/mmc/host/Kconfig                           |   7 +
 drivers/mmc/host/Makefile                          |   1 +
 drivers/mmc/host/meson-mmc.c                       | 527 +++++++++++++++++++++
 4 files changed, 564 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/meson-mmc.txt
 create mode 100644 drivers/mmc/host/meson-mmc.c

Documentation/devicetree/bindings/mmc/meson-mmc.txt new file +4 -0

new file mode 100644
index 0000000..7ff9e9e
@@ -0,0 +1,29 @@
+* Amlogic MesonX MMC controller
+
+The highspeed MMC host controller on Amlogic SoCs provides an interface
+for MMC, SD, SDIO and SDHC types of memory cards.

Documentation/devicetree/bindings/mmc/meson-mmc.txt new file +5 -0

+ - pinctrl-0: Should specify pin control groups used for this controller
+
+Optional properties:
+ - for cd, bus-width and additional generic mmc parameters
+   please refer to mmc.txt within this directory

drivers/mmc/host/Kconfig +7 -0

index 1dee533..7f2c5ae 100644
@@ -765,6 +765,13 @@ config MMC_REALTEK_USB
          Say Y here to include driver code to support SD/MMC card interface
          of Realtek RTS5129/39 series card reader
 
+config MMC_MESON
+       tristate "Amlogic MesonX SD/MMC Host Controller support"
+       depends on ARCH_MESON
+       help
+         This selects support for the SD/MMC Host Controller on
+         Amlogic MesonX SoCs.
+
 config MMC_SUNXI
        tristate "Allwinner sunxi SD/MMC Host Controller support"
        depends on ARCH_SUNXI

drivers/mmc/host/Makefile +1 -0

index 3595f83..26ddf76 100644
@@ -54,6 +54,7 @@ obj-$(CONFIG_MMC_VUB300)      += vub300.o
 obj-$(CONFIG_MMC_USHC)         += ushc.o
 obj-$(CONFIG_MMC_WMT)          += wmt-sdmmc.o
 obj-$(CONFIG_MMC_MOXART)       += moxart-mmc.o
+obj-$(CONFIG_MMC_MESON)                += meson-mmc.o
 obj-$(CONFIG_MMC_SUNXI)                += sunxi-mmc.o
 obj-$(CONFIG_MMC_USDHI6ROL0)   += usdhi6rol0.o
 obj-$(CONFIG_MMC_TOSHIBA_PCI)  += toshsd.o

drivers/mmc/host/meson-mmc.c new file +98 -0

new file mode 100644
index 0000000..6382470
@@ -0,0 +1,527 @@
+/*
+ * meson-mmc.c - Meson SDH Controller
+ *
+ * Copyright (C) 2015 Endless Mobile, Inc.
+ * Author: Carlo Caione <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/slot-gpio.h>
+
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+
+#define SDIO_ARGU              (0x00)
+#define SDIO_SEND              (0x04)
+#define SDIO_CONF              (0x08)
+#define SDIO_IRQS              (0x0c)
+#define SDIO_IRQC              (0x10)
+#define SDIO_MULT              (0x14)
+#define SDIO_ADDR              (0x18)
+#define SDIO_EXT               (0x1c)
+
+#define REG_IRQS_RESP_CRC7     BIT(5)
+#define REG_IRQS_RD_CRC16      BIT(6)
+#define REG_IRQS_WR_CRC16      BIT(7)
+#define REG_IRQS_CMD_INT       BIT(9)
+
+#define REG_IRQC_ARC_CMD_INT   BIT(4)
+
+#define REG_CONF_CLK_DIV_M     (0x3ff)
+#define REG_CONF_BUS_WIDTH     BIT(20)
+
+#define REG_MULT_PORT_SEL_M    (0x3)
+#define REG_MULT_RD_INDEX_M    (0x0f)
+#define REG_MULT_RD_INDEX_S    (12)
+#define REG_MULT_WR_RD_OUT_IND BIT(8)
+
+#define REG_SEND_CMD_COMMAND_M (0xff)
+#define REG_SEND_CMD_RESP_S    (8)
+#define REG_SEND_RESP_NO_CRC7  BIT(16)
+#define REG_SEND_RESP_HAVE_DATA        BIT(17)
+#define REG_SEND_RESP_CRC7_F_8 BIT(18)
+#define REG_SEND_CHECK_BUSY_D0 BIT(19)
+#define REG_SEND_CMD_SEND_DATA BIT(20)
+#define REG_SEND_REP_PACK_N_M  (0xff)
+#define REG_SEND_REP_PACK_N_S  (24)
+
+#define REG_EXT_DAT_RW_NUM_M   (0x3fff)
+#define REG_EXT_DAT_RW_NUM_S   (16)
+
+#define SDIO_BOUNCE_REQ_SIZE   (128 * 1024)
+
+struct meson_mmc_host {
+       struct mmc_host         *mmc;
+       struct mmc_request      *mrq;
+       struct delayed_work     timeout_work;
+       struct clk              *clk;
+       spinlock_t              lock;
+       void __iomem            *base;
+       long                    timeout;
+       int                     irq;
+       int                     error;
+       unsigned int            port;
+       bool                    cmd_is_stop;
+       bool                    dying;
+};
+
+static int meson_mmc_clk_set_rate(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+       struct meson_mmc_host *host = mmc_priv(mmc);
+       unsigned long clk_rate;
+       unsigned int clk_ios = ios->clock;
+       unsigned int clk_div;
+       u32 conf_reg;
+
+       clk_rate = clk_get_rate(host->clk);
+       if (clk_rate < 0) {
+               dev_err(mmc_dev(mmc), "cannot get clock rate\n");
+               return -EINVAL;
+       }
+

drivers/mmc/host/meson-mmc.c new file +301 -0

+
+       return 0;
+}
+
+static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+       struct meson_mmc_host *host = mmc_priv(mmc);
+       u32 reg;
+
+       reg = readl(host->base + SDIO_CONF);
+
+       switch (ios->bus_width) {
+       case MMC_BUS_WIDTH_1:
+               reg &= ~REG_CONF_BUS_WIDTH;
+               break;
+       case MMC_BUS_WIDTH_4:
+               reg |= REG_CONF_BUS_WIDTH;
+               break;
+       case MMC_BUS_WIDTH_8:
+       default:
+               dev_err(mmc_dev(mmc), "meson controller doesn't support 8bit data bus\n");
+               host->error = -EINVAL;
+               return;
+       }
+
+       writel(reg, host->base + SDIO_CONF);
+
+       if (ios->clock && ios->power_mode)
+               host->error = meson_mmc_clk_set_rate(mmc, ios);
+}
+
+static void meson_mmc_start_cmd(struct mmc_host *mmc,
+                               struct mmc_command *cmd)
+{
+       struct meson_mmc_host *host = mmc_priv(mmc);
+       unsigned int pack_size;
+       u32 irqc, irqs, mult;
+       u32 send = 0;
+       u32 ext = 0;
+
+       switch (mmc_resp_type(cmd)) {
+       case MMC_RSP_R1:
+       case MMC_RSP_R1B:
+       case MMC_RSP_R3:
+               send |= (45 << REG_SEND_CMD_RESP_S);
+               break;
+       case MMC_RSP_R2:
+               send |= (133 << REG_SEND_CMD_RESP_S);
+               send |= REG_SEND_RESP_CRC7_F_8;
+               break;
+       default:
+               break;
+       }
+
+       if (!(cmd->flags & MMC_RSP_CRC))
+               send |= REG_SEND_RESP_NO_CRC7;
+
+       if (cmd->flags & MMC_RSP_BUSY)
+               send |= REG_SEND_CHECK_BUSY_D0;
+
+       if (cmd->data) {
+               send &= ~(REG_SEND_REP_PACK_N_M << REG_SEND_REP_PACK_N_S);
+               send |= ((cmd->data->blocks - 1) << REG_SEND_REP_PACK_N_S);
+
+               ext &= ~(REG_EXT_DAT_RW_NUM_M << REG_EXT_DAT_RW_NUM_S);
+               if (mmc->ios.bus_width)
+                       pack_size = cmd->data->blksz * 8 + (16 - 1) * 4;
+               else
+                       pack_size = cmd->data->blksz * 8 + (16 - 1);
+               ext |= (pack_size << REG_EXT_DAT_RW_NUM_S);
+
+               if (cmd->data->flags & MMC_DATA_WRITE)
+                       send |= REG_SEND_CMD_SEND_DATA;
+               else
+                       send |= REG_SEND_RESP_HAVE_DATA;
+       }
+
+       send &= ~REG_SEND_CMD_COMMAND_M;
+       send |= (0x40 | cmd->opcode);
+
+       irqc = readl(host->base + SDIO_IRQC);
+       irqc |= REG_IRQC_ARC_CMD_INT;
+
+       irqs = readl(host->base + SDIO_IRQS);
+       irqs |= REG_IRQS_CMD_INT;
+
+       mult = readl(host->base + SDIO_MULT);
+       mult &= ~REG_MULT_PORT_SEL_M;
+       mult |= host->port;
+       mult |= (1 << 31);
+       writel(mult, host->base + SDIO_MULT);
+       writel(irqs, host->base + SDIO_IRQS);
+       writel(irqc, host->base + SDIO_IRQC);
+
+       writel(cmd->arg, host->base + SDIO_ARGU);
+       writel(ext, host->base + SDIO_EXT);
+       writel(send, host->base + SDIO_SEND);
+}
+
+static int meson_mmc_map_dma(struct meson_mmc_host *host,
+                            struct mmc_data *data,
+                            unsigned int flags)
+{      u32 dma_len;
+       struct scatterlist *sg = data->sg;
+
+       if (sg->offset & 3 || sg->length & 3) {
+               dev_err(mmc_dev(host->mmc),
+                       "unaligned scatterlist: os %x length %d\n",
+                       sg->offset, sg->length);
+               return -EINVAL;
+       }
+
+       dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+                            ((data->flags & MMC_DATA_READ) ?
+                            DMA_FROM_DEVICE : DMA_TO_DEVICE));
+       if (dma_len == 0) {
+               dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+       struct meson_mmc_host *host = mmc_priv(mmc);
+       struct mmc_command *cmd = mrq->cmd;
+       struct mmc_data *data = mrq->data;
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&host->lock, flags);
+
+       if (host->error) {
+               cmd->error = host->error;
+               spin_unlock_irqrestore(&host->lock, flags);
+               mmc_request_done(mmc, mrq);
+               return;
+       }
+
+       if (data) {
+               ret = meson_mmc_map_dma(host, data, data->flags);
+               if (ret < 0) {
+                       dev_err(mmc_dev(mmc), "map DMA failed\n");
+                       cmd->error = ret;
+                       data->error = ret;
+                       spin_unlock_irqrestore(&host->lock, flags);
+                       mmc_request_done(mmc, mrq);
+                       return;
+               }
+               writel(sg_dma_address(data->sg), host->base + SDIO_ADDR);
+       }
+
+       host->mrq = mrq;
+       meson_mmc_start_cmd(mmc, mrq->cmd);
+
+       spin_unlock_irqrestore(&host->lock, flags);
+
+       schedule_delayed_work(&host->timeout_work, host->timeout);
+}
+
+static irqreturn_t meson_mmc_irq(int irq, void *data)
+{
+       struct meson_mmc_host *host = (void *) data;
+       struct mmc_request *mrq = host->mrq;
+       u32 irqs;
+
+       irqs = readl(host->base + SDIO_IRQS);
+       if (mrq && (irqs & REG_IRQS_CMD_INT))
+               return IRQ_WAKE_THREAD;
+
+       return IRQ_HANDLED;
+}
+
+void meson_mmc_read_response(struct meson_mmc_host *host)
+{
+       struct mmc_command *cmd = host->mrq->cmd;
+       u32 mult;
+       int i, resp[4] = { 0 };
+
+       mult = readl(host->base + SDIO_MULT);
+       mult |= REG_MULT_WR_RD_OUT_IND;
+       mult &= ~(REG_MULT_RD_INDEX_M << REG_MULT_RD_INDEX_S);
+       writel(mult, host->base + SDIO_MULT);
+
+       if (cmd->flags & MMC_RSP_136) {
+               for (i = 0; i <= 3; i++)
+                       resp[3 - i] = readl(host->base + SDIO_ARGU);
+               cmd->resp[0] = (resp[0] << 8) | ((resp[1] >> 24) & 0xff);
+               cmd->resp[1] = (resp[1] << 8) | ((resp[2] >> 24) & 0xff);
+               cmd->resp[2] = (resp[2] << 8) | ((resp[3] >> 24) & 0xff);
+               cmd->resp[3] = (resp[3] << 8);
+       } else if (cmd->flags & MMC_RSP_PRESENT) {
+               cmd->resp[0] = readl(host->base + SDIO_ARGU);
+       }
+}
+
+static irqreturn_t meson_mmc_irq_thread(int irq, void *irq_data)
+{
+       struct meson_mmc_host *host = (void *) irq_data;
+       struct mmc_data *data;
+       unsigned long flags;
+       struct mmc_request *mrq;
+       u32 irqs, send;
+
+       cancel_delayed_work_sync(&host->timeout_work);
+       spin_lock_irqsave(&host->lock, flags);
+
+       mrq = host->mrq;
+       data = mrq->data;
+
+       if (!mrq) {
+               spin_unlock_irqrestore(&host->lock, flags);
+               return IRQ_HANDLED;
+       }
+
+       if (host->cmd_is_stop)
+               goto out;
+
+       irqs = readl(host->base + SDIO_IRQS);
+       send = readl(host->base + SDIO_SEND);
+
+       mrq->cmd->error = 0;
+
+       if (!data) {
+               if (!((irqs & REG_IRQS_RESP_CRC7) ||
+                     (send & REG_SEND_RESP_NO_CRC7)))
+                       mrq->cmd->error = -EILSEQ;
+               else
+                       meson_mmc_read_response(host);
+       } else {
+               if (!((irqs & REG_IRQS_RD_CRC16) ||
+                     (irqs & REG_IRQS_WR_CRC16))) {
+                       mrq->cmd->error = -EILSEQ;
+               } else {
+                       data->bytes_xfered = data->blksz * data->blocks;
+                       dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+                                    ((data->flags & MMC_DATA_READ) ?
+                                    DMA_FROM_DEVICE : DMA_TO_DEVICE));
+               }
+       }
+
+       if (mrq->stop) {
+               host->cmd_is_stop = true;
+               meson_mmc_start_cmd(host->mmc, mrq->stop);
+               spin_unlock_irqrestore(&host->lock, flags);
+               return IRQ_HANDLED;
+       }
+
+out:
+       host->cmd_is_stop = false;
+       host->mrq = NULL;
+       spin_unlock_irqrestore(&host->lock, flags);
+       mmc_request_done(host->mmc, mrq);
+
+       return IRQ_HANDLED;
+}
+
+static void meson_mmc_timeout(struct work_struct *work)
+{
+       struct meson_mmc_host *host = container_of(work,
+                                                  struct meson_mmc_host,
+                                                  timeout_work.work);
+       struct mmc_request *mrq = host->mrq;
+       unsigned long flags;
+       u32 irqc;
+
+       /* Do not run after meson_mmc_remove() */
+       if (host->dying)
+               return;
+
+       spin_lock_irqsave(&host->lock, flags);
+
+       dev_err(mmc_dev(host->mmc), "Timeout on CMD%u\n", mrq->cmd->opcode);
+
+       irqc = readl(host->base + SDIO_IRQC);
+       irqc &= ~REG_IRQC_ARC_CMD_INT;
+       writel(irqc, host->base + SDIO_IRQC);
+
+       mrq->cmd->error = -ETIMEDOUT;
+
+       host->mrq = NULL;
+       spin_unlock_irqrestore(&host->lock, flags);
+
+       mmc_request_done(host->mmc, mrq);
+}
+
+static struct mmc_host_ops meson_mmc_ops = {
+       .request        = meson_mmc_request,
+       .set_ios        = meson_mmc_set_ios,
+       .get_cd         = mmc_gpio_get_cd,
+};
+
+static int meson_mmc_probe(struct platform_device *pdev)
+{
+       struct mmc_host *mmc;
+       struct meson_mmc_host *host;
+       struct pinctrl *pinctrl;
+       struct pinctrl_state *pins;
+       struct resource *res;
+       int ret, irq;

drivers/mmc/host/meson-mmc.c new file +10 -0

+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       host->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(host->base)) {
+               ret = PTR_ERR(host->base);
+               goto error_free_host;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       ret = devm_request_threaded_irq(&pdev->dev, irq, meson_mmc_irq,

drivers/mmc/host/meson-mmc.c new file +22 -0

+
+       /* we do not support scatter lists in hardware */
+       mmc->max_segs = 1;
+       mmc->max_req_size = SDIO_BOUNCE_REQ_SIZE;
+       mmc->max_seg_size = mmc->max_req_size;
+       mmc->max_blk_count = 256;
+       mmc->max_blk_size = mmc->max_req_size / mmc->max_blk_count;
+       mmc->f_min = 300000;
+       mmc->f_max = 50000000;
+       mmc->caps |= MMC_CAP_4_BIT_DATA;
+       mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED;
+       mmc->caps2 |= MMC_CAP2_NO_SDIO;
+       mmc->ocr_avail = MMC_VDD_33_34;
+       mmc->ops = &meson_mmc_ops;
+
+       spin_lock_init(&host->lock);
+
+       INIT_DELAYED_WORK(&host->timeout_work, meson_mmc_timeout);
+
+       pinctrl = devm_pinctrl_get(&pdev->dev);
+       if (IS_ERR(pinctrl)) {
+               ret = PTR_ERR(pinctrl);

drivers/mmc/host/meson-mmc.c new file +56 -1

+       ret = mmc_of_parse(mmc);
+       if (ret)
+               goto error_free_host;
+
+       platform_set_drvdata(pdev, mmc);
+
+       ret = mmc_add_host(mmc);
+       if (ret)
+               goto error_free_host;
+
+       dev_info(&pdev->dev, "base:0x%p irq:%u port:%u\n",
+                host->base, irq, host->port);
+
+       return 0;
+
+error_free_host:
+       mmc_free_host(mmc);
+
+       return ret;
+}
+
+static int meson_mmc_remove(struct platform_device *pdev)
+{
+       struct mmc_host *mmc = platform_get_drvdata(pdev);
+       struct meson_mmc_host *host = mmc_priv(mmc);
+
+       host->dying = true;
+
+       mmc_remove_host(mmc);
+       cancel_delayed_work_sync(&host->timeout_work);
+
+       mmc_free_host(mmc);
+
+       return 0;
+}
+
+static const struct of_device_id meson_mmc_of_match[] = {
+       { .compatible = "amlogic,meson-mmc", },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_mmc_of_match);
+
+static struct platform_driver meson_mmc_driver = {
+       .probe   = meson_mmc_probe,
+       .remove  = meson_mmc_remove,
+       .driver  = {
+               .name = "meson-mmc",
+               .of_match_table = of_match_ptr(meson_mmc_of_match),
+       },
+};
+
+module_platform_driver(meson_mmc_driver);
+
+MODULE_DESCRIPTION("Meson Secure Digital Host Driver");
+MODULE_AUTHOR("Carlo Caione <[email protected]>");
+MODULE_LICENSE("GPL");
--

2.5.0

Quoted 6 lines · Carlo Caione

+Required properties:
+ - compatible : "amlogic,meson-mmc"
+ - reg : mmc controller base registers
+ - interrupts : mmc controller interrupt
+ - clocks : phandle to clock provider
+ - pinctrl-names : should contain "sdio_a" or "sdio_b"

This is weird. I don't think you need this specific states. You should be able to cope with common used "default" state.

Later in the driver code I realize that you have some register bits that is related to either using port a or port b. But I don't think that is the same thing as having different pinctrls states.

If you can't detect whether port a or b is used in runtime by the driver, I suggest you add a separate meson mmc DT binding telling what port is being used.

Quoted 5 lines

+ - pinctrl-0: Should specify pin control groups used for this controller

Documentation/devicetree/bindings/mmc/meson-mmc.txt new file +4 -0

+
+Optional properties:
+ - for cd, bus-width and additional generic mmc parameters
+   please refer to mmc.txt within this directory

Documentation/devicetree/bindings/mmc/meson-mmc.txt line 29

Quoted 10 lines

Documentation/devicetree/bindings/mmc/meson-mmc.txt new file +10 -0

+
+Examples:
+       mmc0: mmc at c1108c20 {
+               pinctrl-names = "sdio_b";
+               pinctrl-0 = <&mmc0_sd_b_pins>;
+               compatible = "amlogic,meson-mmc";
+               reg = <0xc1108c20 0x20>;
+               interrupts = <0 28 1>;
+               clocks = <&clkc CLKID_CLK81>;
+       };

Overall the DT documentation looks okay (beside the comments above). Although, please separate it to become a patch 1/2. The rest below shoud go into a patch 2/2.

For the DT patch please include the DT maintainers when posting the new version.

Quoted 5 lines

drivers/mmc/host/meson-mmc.c new file +5 -0

+       clk_rate >>= 1;
+       clk_div = clk_rate / clk_ios - !(clk_rate % clk_ios);
+
+       conf_reg = readl(host->base + SDIO_CONF);
+       conf_reg &= ~REG_CONF_CLK_DIV_M;

drivers/mmc/host/meson-mmc.c line 108

Quoted 5 lines

drivers/mmc/host/meson-mmc.c new file +5 -0

+       conf_reg |= clk_div;
+       writel(conf_reg, host->base + SDIO_CONF);
+
+       dev_dbg(mmc_dev(mmc), "clk_ios: %d, clk_div: %d, clk_rate: %ld\n",
+               clk_ios, clk_div, clk_rate);

It's good practice to update mmc->actual_clock, as it's being used from mmc core's debugfs support.

drivers/mmc/host/meson-mmc.c line 419

Quoted 4 lines

drivers/mmc/host/meson-mmc.c new file +4 -0

+
+       host = mmc_priv(mmc);
+       host->mmc = mmc;
+       host->timeout = msecs_to_jiffies(2000);

I don't think this timeout will cover all cases, although I can't really tell what a proper value should be as it's dynamically changning between requests.

Perhaps try to pick a value that's already being used by other hosts is good enough!?

Quoted 16 lines

drivers/mmc/host/meson-mmc.c new file +16 -0

+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       host->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(host->base)) {
+               ret = PTR_ERR(host->base);
+               goto error_free_host;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       ret = devm_request_threaded_irq(&pdev->dev, irq, meson_mmc_irq,
+                                       meson_mmc_irq_thread, 0, "meson_mmc",
+                                       host);
+       if (ret)
+               goto error_free_host;
+
+       host->clk = devm_clk_get(&pdev->dev, NULL);

drivers/mmc/host/meson-mmc.c line 439

Quoted 4 lines

drivers/mmc/host/meson-mmc.c new file +4 -0

+       if (IS_ERR(host->clk)) {
+               ret = PTR_ERR(host->clk);
+               goto error_free_host;
+       }

A clk_prepare_enable() is missing somwhere around here and of course then the clock needs to be gated as well. Both in the error handling of ->probe() but also in meson_mmc_remove().

Quoted 27 lines

drivers/mmc/host/meson-mmc.c new file +27 -0

+
+       /* we do not support scatter lists in hardware */
+       mmc->max_segs = 1;
+       mmc->max_req_size = SDIO_BOUNCE_REQ_SIZE;
+       mmc->max_seg_size = mmc->max_req_size;
+       mmc->max_blk_count = 256;
+       mmc->max_blk_size = mmc->max_req_size / mmc->max_blk_count;
+       mmc->f_min = 300000;
+       mmc->f_max = 50000000;
+       mmc->caps |= MMC_CAP_4_BIT_DATA;
+       mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED;
+       mmc->caps2 |= MMC_CAP2_NO_SDIO;
+       mmc->ocr_avail = MMC_VDD_33_34;
+       mmc->ops = &meson_mmc_ops;
+
+       spin_lock_init(&host->lock);
+
+       INIT_DELAYED_WORK(&host->timeout_work, meson_mmc_timeout);
+
+       pinctrl = devm_pinctrl_get(&pdev->dev);
+       if (IS_ERR(pinctrl)) {
+               ret = PTR_ERR(pinctrl);
+               goto error_free_host;
+       }
+
+       /* We need to know at runtime which port we are using */
+       pins = pinctrl_lookup_state(pinctrl, "sdio_b");

drivers/mmc/host/meson-mmc.c line 471

Quoted 5 lines

drivers/mmc/host/meson-mmc.c new file +5 -0

+       if (!IS_ERR(pins))
+               host->port = 1; /* PORT_B */
+       else
+               host->port = 0; /* PORT_A */
+

I think the pinctrl code can be removed, according to my eariler comments for the DT documentation.

Instead you need a way to find out the currently used port...

I have actually a problem and a question related to this value. On the boards I'm currently using to test this driver I have no CD GPIO. In this case do I have to specify the MMC as "non-removable"? Also if I

try to change an SD card at runtime I have to wait 3 times the timeout before being able to do it successfully.

Quoted 3 lines

I have actually a problem and a question related to this value. On the boards I'm currently using to test this driver I have no CD GPIO. In this case do I have to specify the MMC as "non-removable"? Also if I

"non-removable" is intended to be used for eMMC or other cards (SD/SDIO) that is not possible to remove/insert at runtime.

Quoted 2 lines

try to change an SD card at runtime I have to wait 3 times the timeout before being able to do it successfully.

I guess you are using the "broken-cd" binding, which will enable MMC_CAP_NEEDS_POLL and thus the mmc core will poll to detect cards being inserted or removed.

On Tue, Dec 8, 2015 at 9:35 PM, Ulf Hansson <[email protected]> wrote:

Hi Ulf,
(old thread, I know)

Quoted 7 lines

Quoted 3 lines

I have actually a problem and a question related to this value. On the boards I'm currently using to test this driver I have no CD GPIO. In this case do I have to specify the MMC as "non-removable"? Also if I

"non-removable" is intended to be used for eMMC or other cards (SD/SDIO) that is not possible to remove/insert at runtime.

Quoted 6 lines

Quoted 2 lines

try to change an SD card at runtime I have to wait 3 times the timeout before being able to do it successfully.

I guess you are using the "broken-cd" binding, which will enable MMC_CAP_NEEDS_POLL and thus the mmc core will poll to detect cards being inserted or removed.

I still fail to see what the correct behaviour should be. Using the v4 of this driver with a "broken-cd" binding and a timeout of 10s my SD card takes 30s to be identified as removed after I take it out from the SD slot.
Also, if I take it out and insert it again, I still have to wait 30s to be able to access it again. Is this a limitation / bug of my driver or is this the expected behaviour when we do not have a dedicated GPIO for card detection?

Quoted 1 line · Carlo Caione

On Tue, Dec 8, 2015 at 9:35 PM, Ulf Hansson <[email protected]> wrote:

Quoted 8 lines

I still fail to see what the correct behaviour should be. Using the v4 of this driver with a "broken-cd" binding and a timeout of 10s my SD card takes 30s to be identified as removed after I take it out from the SD slot.
Also, if I take it out and insert it again, I still have to wait 30s to be able to access it again. Is this a limitation / bug of my driver or is this the expected behaviour when we do not have a dedicated GPIO for card detection?

It's *not* an expected a behaviour.

Using MMC_CAP_NEEDS_POLL, means that the mmc core will send CMD13 commands in a polling manner to find out whether a card has been removed.

It seems like when the card is removed, the host driver doesn't get an IRQ which indicates a command timeout. Instead it waits for the 10 s timeout to expire.

My question is then; why don't the driver get an IRQ for the command timeout? Is that because of non-correct setup of the IRQ masks or because the controller HW doesn't support this?

Quoted 2 lines · Ulf Hansson

Quoted 1 line · Carlo Caione

On Tue, Dec 8, 2015 at 9:35 PM, Ulf Hansson <[email protected]> wrote:

[cut]

Quoted 19 lines

Quoted 8 lines

I still fail to see what the correct behaviour should be. Using the v4 of this driver with a "broken-cd" binding and a timeout of 10s my SD card takes 30s to be identified as removed after I take it out from the SD slot.
Also, if I take it out and insert it again, I still have to wait 30s to be able to access it again. Is this a limitation / bug of my driver or is this the expected behaviour when we do not have a dedicated GPIO for card detection?

It's *not* an expected a behaviour.

Using MMC_CAP_NEEDS_POLL, means that the mmc core will send CMD13 commands in a polling manner to find out whether a card has been removed.

It seems like when the card is removed, the host driver doesn't get an IRQ which indicates a command timeout. Instead it waits for the 10 s timeout to expire.

Quoted 3 lines

My question is then; why don't the driver get an IRQ for the command timeout? Is that because of non-correct setup of the IRQ masks or because the controller HW doesn't support this?

I just verified that apparently the HW doesn't support this (no register for commands timeout and no IRQ generated). Anything wrong with implementing this in software with a timer on mrq->data->timeout_ns?

On 2 February 2016 at 22:54, Carlo Caione <[email protected]> wrote:

Huh, another broken MMC controller. :-)

In some cases there are no data in the request, it's just a command being sent. So to deal with this issue, you will have to adjust the timer depending on the request we send to the controller.

Quoted 1 line · Ulf Hansson

On 2 February 2016 at 22:54, Carlo Caione <[email protected]> wrote:

[cut]

Quoted 1 line

Huh, another broken MMC controller. :-)

Oh, actually I found in the datasheet a couple of undocumented registers (also not used in the original Amlogic SDK code) that seems to have something to do with timeout (hard to say without proper documentation but they are called "Timeout counter for preload setting and present status" and "Timeout Counter Interrupt Enable for ARC/ARM" so I guess I'm on the right track here).
I briefly tried yesterday to enable this timeout interrupt with a dummy value in the counter register (I have no idea how get this value from the clocking) and it seems working (the counter value is decremented when reading the register upon command completion).

Quoted 4 lines

In some cases there are no data in the request, it's just a command being sent. So to deal with this issue, you will have to adjust the timer depending on the request we send to the controller.

I see that the CMD13 used to poll the card has no data so in that case should we use a fixed / dummy value to use as timeout counter? I'm kind of confused here since the MMC drivers I'm looking at use the hardware timeout register only when the data->timeout_ns is actually present.

From: Carlo Caione <[email protected]>

Add a driver for the SD/MMC host found on the Amlogic MesonX SoCs. This is an MMC controller which provides an interface between the application processor and various memory cards. It supports the SD specification v2.0 and the eMMC specification v4.41.

This patch adds also the binding documentation.