From patchwork Wed Feb 24 19:17:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jae Hyun Yoo X-Patchwork-Id: 387012 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2516EC433E0 for ; Wed, 24 Feb 2021 19:08:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF94B64F1B for ; Wed, 24 Feb 2021 19:08:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235187AbhBXTHz (ORCPT ); Wed, 24 Feb 2021 14:07:55 -0500 Received: from mga05.intel.com ([192.55.52.43]:47725 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236014AbhBXTHs (ORCPT ); Wed, 24 Feb 2021 14:07:48 -0500 IronPort-SDR: PHJxm/2K09S4rqOz2wWlhyeRROReuWnpxrAVN6mHsTkwyk/R/eGWSflBWg1vn5DDglTNmf6JGH j6AfOre9PRcw== X-IronPort-AV: E=McAfee;i="6000,8403,9905"; a="270243446" X-IronPort-AV: E=Sophos;i="5.81,203,1610438400"; d="scan'208";a="270243446" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2021 11:04:34 -0800 IronPort-SDR: RGI7Uo3MVhDUBI/KPv/KhjVwX4FPoRivLE2pBqG24WRGafMwhIwko3CNnr0MA94ftYt/NkDwxO Hv80nwZyGWFw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,203,1610438400"; d="scan'208";a="367098945" Received: from maru.jf.intel.com ([10.54.51.77]) by orsmga006.jf.intel.com with ESMTP; 24 Feb 2021 11:04:34 -0800 From: Jae Hyun Yoo To: Brendan Higgins , Wolfram Sang , Benjamin Herrenschmidt , Joel Stanley , Rob Herring , Mark Rutland , Andrew Jeffery , Tao Ren , Cedric Le Goater Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org, openbmc@lists.ozlabs.org, Jae Hyun Yoo Subject: [PATCH v4 4/4] i2c: aspeed: add DMA mode transfer support Date: Wed, 24 Feb 2021 11:17:20 -0800 Message-Id: <20210224191720.7724-5-jae.hyun.yoo@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210224191720.7724-1-jae.hyun.yoo@linux.intel.com> References: <20210224191720.7724-1-jae.hyun.yoo@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org This commit adds DMA mode transfer support. Only AST2500 and later versions support DMA mode. AST2500 has these restrictions: - If one of these controllers is enabled * UHCI host controller * MCTP controller I2C has to use buffer mode or byte mode instead since these controllers run only in DMA mode and I2C is sharing the same DMA H/W with them. - If one of these controllers uses DMA mode, I2C can't use DMA mode * SD/eMMC * Port80 snoop Signed-off-by: Jae Hyun Yoo --- Changes since v3: - None Changes since v2: - Refined SoC family dependent xfer mode configuration functions. Changes since v1: - Updated commit message and comments. - Refined using abstract functions. drivers/i2c/busses/i2c-aspeed.c | 265 ++++++++++++++++++++++++++------ 1 file changed, 216 insertions(+), 49 deletions(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index ffc52937df26..3e3bb014b027 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -10,6 +10,8 @@ #include #include #include +#include +#include #include #include #include @@ -47,6 +49,8 @@ #define ASPEED_I2C_DEV_ADDR_REG 0x18 #define ASPEED_I2C_BUF_CTRL_REG 0x1c #define ASPEED_I2C_BYTE_BUF_REG 0x20 +#define ASPEED_I2C_DMA_ADDR_REG 0x24 +#define ASPEED_I2C_DMA_LEN_REG 0x28 /* Device Register Definition */ /* 0x00 : I2CD Function Control Register */ @@ -111,6 +115,8 @@ #define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11) /* Command Bit */ +#define ASPEED_I2CD_RX_DMA_ENABLE BIT(9) +#define ASPEED_I2CD_TX_DMA_ENABLE BIT(8) #define ASPEED_I2CD_RX_BUFF_ENABLE BIT(7) #define ASPEED_I2CD_TX_BUFF_ENABLE BIT(6) #define ASPEED_I2CD_M_STOP_CMD BIT(5) @@ -136,6 +142,14 @@ #define ASPEED_I2CD_BUF_TX_COUNT_MASK GENMASK(15, 8) #define ASPEED_I2CD_BUF_OFFSET_MASK GENMASK(5, 0) +/* 0x24 : I2CD DMA Mode Buffer Address Register */ +#define ASPEED_I2CD_DMA_ADDR_MASK GENMASK(31, 2) +#define ASPEED_I2CD_DMA_ALIGN 4 + +/* 0x28 : I2CD DMA Transfer Length Register */ +#define ASPEED_I2CD_DMA_LEN_SHIFT 0 +#define ASPEED_I2CD_DMA_LEN_MASK GENMASK(11, 0) + enum aspeed_i2c_master_state { ASPEED_I2C_MASTER_INACTIVE, ASPEED_I2C_MASTER_PENDING, @@ -161,6 +175,7 @@ struct aspeed_i2c_config { u32 (*get_clk_reg_val)(struct device *dev, u32 divisor); int (*enable_sram)(void); int (*set_buf_xfer_mode)(struct device *dev); + int (*set_dma_xfer_mode)(struct device *dev); }; struct aspeed_i2c_bus { @@ -190,6 +205,12 @@ struct aspeed_i2c_bus { void __iomem *buf_base; u8 buf_offset; u8 buf_page; + /* DMA mode */ + struct dma_pool *dma_pool; + dma_addr_t dma_handle; + u8 *dma_buf; + size_t dma_len; + /* Buffer/DMA mode */ size_t buf_size; #if IS_ENABLED(CONFIG_I2C_SLAVE) struct i2c_client *slave; @@ -272,9 +293,13 @@ static inline void aspeed_i2c_slave_handle_rx_done(struct aspeed_i2c_bus *bus, u32 irq_status, u8 *value) { - if (bus->buf_base && + if (bus->dma_buf && bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED && !(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP)) + *value = bus->dma_buf[0]; + else if (bus->buf_base && + bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED && + !(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP)) *value = readb(bus->buf_base); else *value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8; @@ -288,7 +313,18 @@ aspeed_i2c_slave_handle_normal_stop(struct aspeed_i2c_bus *bus, u32 irq_status, if (bus->slave_state == ASPEED_I2C_SLAVE_WRITE_RECEIVED && irq_status & ASPEED_I2CD_INTR_RX_DONE) { - if (bus->buf_base) { + if (bus->dma_buf) { + len = bus->buf_size - + FIELD_GET(ASPEED_I2CD_DMA_LEN_MASK, + readl(bus->base + + ASPEED_I2C_DMA_LEN_REG)); + for (i = 0; i < len; i++) { + *value = bus->dma_buf[i]; + i2c_slave_event(bus->slave, + I2C_SLAVE_WRITE_RECEIVED, + value); + } + } else if (bus->buf_base) { len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK, readl(bus->base + ASPEED_I2C_BUF_CTRL_REG)); @@ -305,7 +341,14 @@ aspeed_i2c_slave_handle_normal_stop(struct aspeed_i2c_bus *bus, u32 irq_status, static inline void aspeed_i2c_slave_handle_write_requested(struct aspeed_i2c_bus *bus, u8 *value) { - if (bus->buf_base) { + if (bus->dma_buf) { + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, bus->buf_size), + bus->base + ASPEED_I2C_DMA_LEN_REG); + writel(ASPEED_I2CD_RX_DMA_ENABLE, + bus->base + ASPEED_I2C_CMD_REG); + } else if (bus->buf_base) { writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK, bus->buf_size - 1) | FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK, @@ -321,7 +364,23 @@ aspeed_i2c_slave_handle_write_received(struct aspeed_i2c_bus *bus, u8 *value) { int i, len; - if (bus->buf_base) { + if (bus->dma_buf) { + len = bus->buf_size - + FIELD_GET(ASPEED_I2CD_DMA_LEN_MASK, + readl(bus->base + + ASPEED_I2C_DMA_LEN_REG)); + for (i = 1; i < len; i++) { + *value = bus->dma_buf[i]; + i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_RECEIVED, + value); + } + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, bus->buf_size), + bus->base + ASPEED_I2C_DMA_LEN_REG); + writel(ASPEED_I2CD_RX_DMA_ENABLE, + bus->base + ASPEED_I2C_CMD_REG); + } else if (bus->buf_base) { len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK, readl(bus->base + ASPEED_I2C_BUF_CTRL_REG)); @@ -451,7 +510,15 @@ aspeed_i2c_prepare_rx_buf(struct aspeed_i2c_bus *bus, struct i2c_msg *msg) command |= ASPEED_I2CD_M_S_RX_CMD_LAST; } - if (bus->buf_base) { + if (bus->dma_buf) { + command |= ASPEED_I2CD_RX_DMA_ENABLE; + + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, len), + bus->base + ASPEED_I2C_DMA_LEN_REG); + bus->dma_len = len; + } else { command |= ASPEED_I2CD_RX_BUFF_ENABLE; writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK, len - 1) | @@ -474,7 +541,18 @@ aspeed_i2c_prepare_tx_buf(struct aspeed_i2c_bus *bus, struct i2c_msg *msg) else len = msg->len + 1; - if (bus->buf_base) { + if (bus->dma_buf) { + command |= ASPEED_I2CD_TX_DMA_ENABLE; + + bus->dma_buf[0] = slave_addr; + memcpy(bus->dma_buf + 1, msg->buf, len); + + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, len), + bus->base + ASPEED_I2C_DMA_LEN_REG); + bus->dma_len = len; + } else { u8 wbuf[4]; int i; @@ -527,18 +605,19 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus) if (msg->flags & I2C_M_RD) { command |= ASPEED_I2CD_M_RX_CMD; if (!(msg->flags & I2C_M_RECV_LEN)) { - if (msg->len && bus->buf_base) + if (msg->len && (bus->dma_buf || bus->buf_base)) command |= aspeed_i2c_prepare_rx_buf(bus, msg); /* Need to let the hardware know to NACK after RX. */ if (msg->len <= 1) command |= ASPEED_I2CD_M_S_RX_CMD_LAST; } - } else if (msg->len && bus->buf_base) { + } else if (msg->len && (bus->dma_buf || bus->buf_base)) { command |= aspeed_i2c_prepare_tx_buf(bus, msg); } - if (!(command & ASPEED_I2CD_TX_BUFF_ENABLE)) + if (!(command & (ASPEED_I2CD_TX_BUFF_ENABLE | + ASPEED_I2CD_TX_DMA_ENABLE))) writel(i2c_8bit_addr_from_msg(msg), bus->base + ASPEED_I2C_BYTE_BUF_REG); writel(command, bus->base + ASPEED_I2C_CMD_REG); @@ -581,42 +660,55 @@ aspeed_i2c_master_handle_tx_first(struct aspeed_i2c_bus *bus, { u32 command = 0; - if (bus->buf_base) { - u8 wbuf[4]; + if (bus->dma_buf || bus->buf_base) { int len; - int i; if (msg->len - bus->buf_index > bus->buf_size) len = bus->buf_size; else len = msg->len - bus->buf_index; - command |= ASPEED_I2CD_TX_BUFF_ENABLE; + if (bus->dma_buf) { + command |= ASPEED_I2CD_TX_DMA_ENABLE; - if (msg->len - bus->buf_index > bus->buf_size) - len = bus->buf_size; - else - len = msg->len - bus->buf_index; + memcpy(bus->dma_buf, msg->buf + bus->buf_index, len); - /* - * Looks bad here again but use dword writings to avoid data - * corruption of byte writing on remapped I2C SRAM. - */ - for (i = 0; i < len; i++) { - wbuf[i % 4] = msg->buf[bus->buf_index + i]; - if (i % 4 == 3) + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, len), + bus->base + ASPEED_I2C_DMA_LEN_REG); + bus->dma_len = len; + } else { + u8 wbuf[4]; + int i; + + command |= ASPEED_I2CD_TX_BUFF_ENABLE; + + if (msg->len - bus->buf_index > bus->buf_size) + len = bus->buf_size; + else + len = msg->len - bus->buf_index; + + /* + * Looks bad here again but use dword writings to avoid + * data corruption of byte writing on remapped I2C SRAM. + */ + for (i = 0; i < len; i++) { + wbuf[i % 4] = msg->buf[bus->buf_index + i]; + if (i % 4 == 3) + writel(*(u32 *)wbuf, + bus->buf_base + i - 3); + } + if (--i % 4 != 3) writel(*(u32 *)wbuf, - bus->buf_base + i - 3); - } - if (--i % 4 != 3) - writel(*(u32 *)wbuf, - bus->buf_base + i - (i % 4)); + bus->buf_base + i - (i % 4)); - writel(FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK, - len - 1) | - FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK, - bus->buf_offset), - bus->base + ASPEED_I2C_BUF_CTRL_REG); + writel(FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK, + len - 1) | + FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK, + bus->buf_offset), + bus->base + ASPEED_I2C_BUF_CTRL_REG); + } bus->buf_index += len; } else { @@ -633,7 +725,14 @@ aspeed_i2c_master_handle_rx(struct aspeed_i2c_bus *bus, struct i2c_msg *msg) u8 recv_byte; int len; - if (bus->buf_base) { + if (bus->dma_buf) { + len = bus->dma_len - + FIELD_GET(ASPEED_I2CD_DMA_LEN_MASK, + readl(bus->base + ASPEED_I2C_DMA_LEN_REG)); + + memcpy(msg->buf + bus->buf_index, bus->dma_buf, len); + bus->buf_index += len; + } else if (bus->buf_base) { len = FIELD_GET(ASPEED_I2CD_BUF_RX_COUNT_MASK, readl(bus->base + ASPEED_I2C_BUF_CTRL_REG)); memcpy_fromio(msg->buf + bus->buf_index, bus->buf_base, len); @@ -650,7 +749,7 @@ aspeed_i2c_master_handle_rx_next(struct aspeed_i2c_bus *bus, { u32 command = 0; - if (bus->buf_base) { + if (bus->dma_buf || bus->buf_base) { int len; if (msg->len - bus->buf_index > bus->buf_size) { @@ -660,14 +759,24 @@ aspeed_i2c_master_handle_rx_next(struct aspeed_i2c_bus *bus, command |= ASPEED_I2CD_M_S_RX_CMD_LAST; } - command |= ASPEED_I2CD_RX_BUFF_ENABLE; + if (bus->dma_buf) { + command |= ASPEED_I2CD_RX_DMA_ENABLE; - writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK, - len - 1) | - FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK, 0) | - FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK, - bus->buf_offset), - bus->base + ASPEED_I2C_BUF_CTRL_REG); + writel(bus->dma_handle & ASPEED_I2CD_DMA_ADDR_MASK, + bus->base + ASPEED_I2C_DMA_ADDR_REG); + writel(FIELD_PREP(ASPEED_I2CD_DMA_LEN_MASK, len), + bus->base + ASPEED_I2C_DMA_LEN_REG); + bus->dma_len = len; + } else { + command |= ASPEED_I2CD_RX_BUFF_ENABLE; + + writel(FIELD_PREP(ASPEED_I2CD_BUF_RX_SIZE_MASK, + len - 1) | + FIELD_PREP(ASPEED_I2CD_BUF_TX_COUNT_MASK, 0) | + FIELD_PREP(ASPEED_I2CD_BUF_OFFSET_MASK, + bus->buf_offset), + bus->base + ASPEED_I2C_BUF_CTRL_REG); + } } else { if (bus->buf_index + 1 == msg->len) command |= ASPEED_I2CD_M_S_RX_CMD_LAST; @@ -1287,22 +1396,63 @@ static int aspeed_i2c_25xx_set_buf_xfer_mode(struct device *dev) return bus->buf_size ? 0 : -EINVAL; } +static int aspeed_i2c_24xx_set_dma_xfer_mode(struct device *dev) +{ + /* AST24xx doesn't support DMA mode */ + + return -EBADR; +} + +static int aspeed_i2c_25xx_set_dma_xfer_mode(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev); + int ret; + + ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); + if (!ret) { + bus->buf_size = ASPEED_I2CD_DMA_LEN_MASK >> + ASPEED_I2CD_DMA_LEN_SHIFT; + bus->dma_pool = dma_pool_create("i2c-aspeed", + &pdev->dev, + bus->buf_size, + ASPEED_I2CD_DMA_ALIGN, + 0); + if (bus->dma_pool) + bus->dma_buf = dma_pool_alloc(bus->dma_pool, + GFP_KERNEL, + &bus->dma_handle); + + if (!bus->dma_buf) { + ret = -ENOMEM; + bus->buf_size = 0; + dev_dbg(&pdev->dev, "Cannot allocate DMA buffer\n"); + dma_pool_destroy(bus->dma_pool); + } + } + + return ret; +} + static const struct aspeed_i2c_config ast24xx_config = { .get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val, .enable_sram = aspeed_i2c_24xx_enable_sram, .set_buf_xfer_mode = aspeed_i2c_24xx_set_buf_xfer_mode, + .set_dma_xfer_mode = aspeed_i2c_24xx_set_dma_xfer_mode, }; static const struct aspeed_i2c_config ast25xx_config = { .get_clk_reg_val = aspeed_i2c_25xx_get_clk_reg_val, .enable_sram = aspeed_i2c_25xx_enable_sram, .set_buf_xfer_mode = aspeed_i2c_25xx_set_buf_xfer_mode, + .set_dma_xfer_mode = aspeed_i2c_25xx_set_dma_xfer_mode, }; static const struct aspeed_i2c_config ast26xx_config = { .get_clk_reg_val = aspeed_i2c_25xx_get_clk_reg_val, .enable_sram = aspeed_i2c_24xx_enable_sram, .set_buf_xfer_mode = aspeed_i2c_25xx_set_buf_xfer_mode, + .set_dma_xfer_mode = aspeed_i2c_25xx_set_dma_xfer_mode, }; static const struct of_device_id aspeed_i2c_bus_of_table[] = { @@ -1324,8 +1474,12 @@ static void aspeed_i2c_set_xfer_mode(struct aspeed_i2c_bus *bus) return; ret = bus->config->enable_sram(); - if (!ret && !strncasecmp(mode, "buf", 3)) - ret = bus->config->set_buf_xfer_mode(bus->dev); + if (!ret) { + if (!strncasecmp(mode, "buf", 3)) + ret = bus->config->set_buf_xfer_mode(bus->dev); + else if (!strncasecmp(mode, "dma", 3)) + ret = bus->config->set_dma_xfer_mode(bus->dev); + } if (ret) dev_dbg(&pdev->dev, "Use default (byte) xfer mode\n"); @@ -1400,22 +1554,31 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) */ ret = aspeed_i2c_init(bus, pdev); if (ret < 0) - return ret; + goto out_free_dma_buf; irq = irq_of_parse_and_map(pdev->dev.of_node, 0); ret = devm_request_irq(&pdev->dev, irq, aspeed_i2c_bus_irq, 0, dev_name(&pdev->dev), bus); if (ret < 0) - return ret; + goto out_free_dma_buf; ret = i2c_add_adapter(&bus->adap); if (ret < 0) - return ret; + goto out_free_dma_buf; dev_info(bus->dev, "i2c bus %d registered (%s mode), irq %d\n", - bus->adap.nr, bus->buf_base ? "buf" : "byte", irq); + bus->adap.nr, bus->dma_buf ? "dma" : + bus->buf_base ? "buf" : "byte", + irq); return 0; + +out_free_dma_buf: + if (bus->dma_buf) + dma_pool_free(bus->dma_pool, bus->dma_buf, bus->dma_handle); + dma_pool_destroy(bus->dma_pool); + + return ret; } static int aspeed_i2c_remove_bus(struct platform_device *pdev) @@ -1433,6 +1596,10 @@ static int aspeed_i2c_remove_bus(struct platform_device *pdev) reset_control_assert(bus->rst); + if (bus->dma_buf) + dma_pool_free(bus->dma_pool, bus->dma_buf, bus->dma_handle); + dma_pool_destroy(bus->dma_pool); + i2c_del_adapter(&bus->adap); return 0;