From patchwork Tue Feb 19 11:40:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yash Shah X-Patchwork-Id: 10819713 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5D3396C2 for ; Tue, 19 Feb 2019 11:40:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A7362B63D for ; Tue, 19 Feb 2019 11:40:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3EB652B677; Tue, 19 Feb 2019 11:40:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DF3E62B6FA for ; Tue, 19 Feb 2019 11:40:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbfBSLkv (ORCPT ); Tue, 19 Feb 2019 06:40:51 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:46094 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727048AbfBSLkv (ORCPT ); Tue, 19 Feb 2019 06:40:51 -0500 Received: by mail-pl1-f194.google.com with SMTP id o6so10319935pls.13 for ; Tue, 19 Feb 2019 03:40:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=HIz4WqHdWYeQ3lkgJK9b2XM4IGZAxsw+zj/jLhdUw3c=; b=jPXPgTjADVt2+smuFo/EEaOowKhqwX/01aQQpu94dpBEHTRqdZHCopqJ48PyFWUn17 7KY8rIbKUV0L7zhDsDIbs7H3i7rOrmEXdlHQBwYSZ5KJXr3ivJiSOuLxL9VtQploH7vh 7Ens8nI7UIuMaOKegIVWFfkYf62F/5wwxmXF3z7TXW+7WXASELjtG+uSqVbhl8RRYdJe ZowRGNrjstb/mKNMQ7t+il98T+91tjjz/gi3hpA9M11smQuV0WF7E3T9I34qPlxpPCqK mM7OO602/MJCNBkpR1OxbraamnM5CfA4PnM8PXu+68VbiIlNQxOeZ3qoGSFz41kUvv8i nqKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=HIz4WqHdWYeQ3lkgJK9b2XM4IGZAxsw+zj/jLhdUw3c=; b=YW8ha51iYyHQ2LnblX0F0gDOfCkk6OWWM/oIEUNj7FuoK5bHHrjD2hz9J5naXGdPDb xob8GwdQ30u8/6kVDMVSqwJu8cdUWRDwW4ek1TSBN2nJ8ZqVtx20Xu0Ebi2bYnQFkJVq A+fB9lEWtf4D/yGNTUPY8lw1XOX8IXTU9KFSh+JSzN+XeGalIv4TAVpCAOQUneZO4LVB uVHYyZPpVbwG325cR4Y5xkd7T1MX88lsq1Oiree+E1m6WaiwjWzwbCLCRlzD2tkzEnJw DJJIK3UPY4HfSij4J2wO6Tp4SuVzuzcfgEYo9DrltNnnX0PxASuxQEGiXX5h/wsPofbz MIkw== X-Gm-Message-State: AHQUAuaB0ib/yQGAllszm77zaarETVKCukWzieQ/CvLQmUtwsDzBl2IF 7pESNZUT6fan1v5PFyYHUbk5y7puzGk= X-Google-Smtp-Source: AHgI3Ia4opb4C4j1RKzH/PI1euLWE6o1bbHCPXTT8YroDhOvbZoZL+hUVjvkrJu+a5QTkLZ7sMeHrw== X-Received: by 2002:a17:902:a514:: with SMTP id s20mr20268782plq.242.1550576450476; Tue, 19 Feb 2019 03:40:50 -0800 (PST) Received: from buildserver-90.open-silicon.com ([114.143.65.226]) by smtp.googlemail.com with ESMTPSA id t3sm32250678pfa.50.2019.02.19.03.40.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 19 Feb 2019 03:40:49 -0800 (PST) From: Yash Shah To: palmer@sifive.com, linux-spi@vger.kernel.org, linux-riscv@lists.infradead.org, broonie@kernel.org Cc: robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sachin.ghadi@sifive.com, paul.walmsley@sifive.com, Yash Shah Subject: [PATCH 1/2] spi: sifive: Add DT documentation for SiFive SPI controller Date: Tue, 19 Feb 2019 17:10:06 +0530 Message-Id: <1550576407-17778-2-git-send-email-yash.shah@sifive.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1550576407-17778-1-git-send-email-yash.shah@sifive.com> References: <1550576407-17778-1-git-send-email-yash.shah@sifive.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP DT documentation for SPI controller added. Signed-off-by: Palmer Dabbelt Signed-off-by: Emil Renner Berthing Signed-off-by: Yash Shah --- .../devicetree/bindings/spi/spi-sifive.txt | 37 ++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 Documentation/devicetree/bindings/spi/spi-sifive.txt diff --git a/Documentation/devicetree/bindings/spi/spi-sifive.txt b/Documentation/devicetree/bindings/spi/spi-sifive.txt new file mode 100644 index 0000000..3f5c6e4 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi-sifive.txt @@ -0,0 +1,37 @@ +SiFive SPI controller Device Tree Bindings +------------------------------------------ + +Required properties: +- compatible : Should be "sifive,-spi" and "sifive,spi". + Supported compatible strings are: + "sifive,fu540-c000-spi" for the SiFive SPI v0 as integrated + onto the SiFive FU540 chip, and "sifive,spi0" for the SiFive + SPI v0 IP block with no chip integration tweaks. + Please refer to sifive-blocks-ip-versioning.txt for details +- reg : Physical base address and size of SPI registers map + A second (optional) range can indicate memory mapped flash +- interrupts : Must contain one entry +- interrupt-parent : Must be core interrupt controller +- clocks : Must reference the frequency given to the controller +- #address-cells : Must be '1', indicating which CS to use +- #size-cells : Must be '0' + +Optional properties: +- sifive,fifo-depth : Depth of hardware queues; defaults to 8 +- sifive,max-bits-per-word : Maximum bits per word; defaults to 8 + +SPI RTL that corresponds to the IP block version numbers can be found here: +https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/spi + +Example: + spi: spi@10040000 { + compatible = "sifive,fu540-c000-spi", "sifive,spi0"; + reg = <0x0 0x10040000 0x0 0x1000 0x0 0x20000000 0x0 0x10000000>; + interrupt-parent = <&plic>; + interrupts = <51>; + clocks = <&tlclk>; + #address-cells = <1>; + #size-cells = <0>; + sifive,fifo-depth = <8>; + sifive,max-bits-per-word = <8>; + }; From patchwork Tue Feb 19 11:40:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yash Shah X-Patchwork-Id: 10819717 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BE865180E for ; Tue, 19 Feb 2019 11:41:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AB0802B4FA for ; 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Tue, 19 Feb 2019 03:40:56 -0800 (PST) Received: from buildserver-90.open-silicon.com ([114.143.65.226]) by smtp.googlemail.com with ESMTPSA id t3sm32250678pfa.50.2019.02.19.03.40.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 19 Feb 2019 03:40:55 -0800 (PST) From: Yash Shah To: palmer@sifive.com, linux-spi@vger.kernel.org, linux-riscv@lists.infradead.org, broonie@kernel.org Cc: robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sachin.ghadi@sifive.com, paul.walmsley@sifive.com, Yash Shah Subject: [PATCH 2/2] spi: sifive: Add driver for the SiFive SPI controller Date: Tue, 19 Feb 2019 17:10:07 +0530 Message-Id: <1550576407-17778-3-git-send-email-yash.shah@sifive.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1550576407-17778-1-git-send-email-yash.shah@sifive.com> References: <1550576407-17778-1-git-send-email-yash.shah@sifive.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add driver for the SiFive SPI controller on the HiFive Unleashed board. Signed-off-by: Palmer Dabbelt Signed-off-by: Emil Renner Berthing Signed-off-by: Yash Shah --- drivers/spi/Kconfig | 6 + drivers/spi/Makefile | 1 + drivers/spi/spi-sifive.c | 450 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 457 insertions(+) create mode 100644 drivers/spi/spi-sifive.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 9f89cb1..f129343 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -631,6 +631,12 @@ config SPI_SH_HSPI help SPI driver for SuperH HSPI blocks. +config SPI_SIFIVE + tristate "SiFive SPI controller" + depends on HAS_IOMEM + help + This exposes the SPI controller IP from SiFive. + config SPI_SIRF tristate "CSR SiRFprimaII SPI controller" depends on SIRF_DMA diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index f296270..7afdc97 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_SPI_SH) += spi-sh.o obj-$(CONFIG_SPI_SH_HSPI) += spi-sh-hspi.o obj-$(CONFIG_SPI_SH_MSIOF) += spi-sh-msiof.o obj-$(CONFIG_SPI_SH_SCI) += spi-sh-sci.o +obj-$(CONFIG_SPI_SIFIVE) += spi-sifive.o obj-$(CONFIG_SPI_SIRF) += spi-sirf.o obj-$(CONFIG_SPI_SLAVE_MT27XX) += spi-slave-mt27xx.o obj-$(CONFIG_SPI_SPRD) += spi-sprd.o diff --git a/drivers/spi/spi-sifive.c b/drivers/spi/spi-sifive.c new file mode 100644 index 0000000..961307c --- /dev/null +++ b/drivers/spi/spi-sifive.c @@ -0,0 +1,450 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright 2018 SiFive, Inc. +// +// SiFive SPI controller driver (master mode only) +// +// Author: SiFive, Inc. +// sifive@sifive.com + +#include +#include +#include +#include +#include +#include +#include +#include + +#define SIFIVE_SPI_DRIVER_NAME "sifive_spi" + +#define SIFIVE_SPI_MAX_CS 32 +#define SIFIVE_SPI_DEFAULT_DEPTH 8 +#define SIFIVE_SPI_DEFAULT_MAX_BITS 8 + +/* register offsets */ +#define SIFIVE_SPI_REG_SCKDIV 0x00 /* Serial clock divisor */ +#define SIFIVE_SPI_REG_SCKMODE 0x04 /* Serial clock mode */ +#define SIFIVE_SPI_REG_CSID 0x10 /* Chip select ID */ +#define SIFIVE_SPI_REG_CSDEF 0x14 /* Chip select default */ +#define SIFIVE_SPI_REG_CSMODE 0x18 /* Chip select mode */ +#define SIFIVE_SPI_REG_DELAY0 0x28 /* Delay control 0 */ +#define SIFIVE_SPI_REG_DELAY1 0x2c /* Delay control 1 */ +#define SIFIVE_SPI_REG_FMT 0x40 /* Frame format */ +#define SIFIVE_SPI_REG_TXDATA 0x48 /* Tx FIFO data */ +#define SIFIVE_SPI_REG_RXDATA 0x4c /* Rx FIFO data */ +#define SIFIVE_SPI_REG_TXMARK 0x50 /* Tx FIFO watermark */ +#define SIFIVE_SPI_REG_RXMARK 0x54 /* Rx FIFO watermark */ +#define SIFIVE_SPI_REG_FCTRL 0x60 /* SPI flash interface control */ +#define SIFIVE_SPI_REG_FFMT 0x64 /* SPI flash instruction format */ +#define SIFIVE_SPI_REG_IE 0x70 /* Interrupt Enable Register */ +#define SIFIVE_SPI_REG_IP 0x74 /* Interrupt Pendings Register */ + +/* sckdiv bits */ +#define SIFIVE_SPI_SCKDIV_DIV_MASK 0xfffU + +/* sckmode bits */ +#define SIFIVE_SPI_SCKMODE_PHA BIT(0) +#define SIFIVE_SPI_SCKMODE_POL BIT(1) +#define SIFIVE_SPI_SCKMODE_MODE_MASK (SIFIVE_SPI_SCKMODE_PHA | \ + SIFIVE_SPI_SCKMODE_POL) + +/* csmode bits */ +#define SIFIVE_SPI_CSMODE_MODE_AUTO 0U +#define SIFIVE_SPI_CSMODE_MODE_HOLD 2U +#define SIFIVE_SPI_CSMODE_MODE_OFF 3U + +/* delay0 bits */ +#define SIFIVE_SPI_DELAY0_CSSCK(x) ((u32)(x)) +#define SIFIVE_SPI_DELAY0_CSSCK_MASK 0xffU +#define SIFIVE_SPI_DELAY0_SCKCS(x) ((u32)(x) << 16) +#define SIFIVE_SPI_DELAY0_SCKCS_MASK (0xffU << 16) + +/* delay1 bits */ +#define SIFIVE_SPI_DELAY1_INTERCS(x) ((u32)(x)) +#define SIFIVE_SPI_DELAY1_INTERCS_MASK 0xffU +#define SIFIVE_SPI_DELAY1_INTERXFR(x) ((u32)(x) << 16) +#define SIFIVE_SPI_DELAY1_INTERXFR_MASK (0xffU << 16) + +/* fmt bits */ +#define SIFIVE_SPI_FMT_PROTO_SINGLE 0U +#define SIFIVE_SPI_FMT_PROTO_DUAL 1U +#define SIFIVE_SPI_FMT_PROTO_QUAD 2U +#define SIFIVE_SPI_FMT_PROTO_MASK 3U +#define SIFIVE_SPI_FMT_ENDIAN BIT(2) +#define SIFIVE_SPI_FMT_DIR BIT(3) +#define SIFIVE_SPI_FMT_LEN(x) ((u32)(x) << 16) +#define SIFIVE_SPI_FMT_LEN_MASK (0xfU << 16) + +/* txdata bits */ +#define SIFIVE_SPI_TXDATA_DATA_MASK 0xffU +#define SIFIVE_SPI_TXDATA_FULL BIT(31) + +/* rxdata bits */ +#define SIFIVE_SPI_RXDATA_DATA_MASK 0xffU +#define SIFIVE_SPI_RXDATA_EMPTY BIT(31) + +/* ie and ip bits */ +#define SIFIVE_SPI_IP_TXWM BIT(0) +#define SIFIVE_SPI_IP_RXWM BIT(1) + +struct sifive_spi { + void __iomem *regs; /* virt. address of control registers */ + struct clk *clk; /* bus clock */ + unsigned int fifo_depth; /* fifo depth in words */ + u32 cs_inactive; /* level of the CS pins when inactive */ + struct completion done; /* wake-up from interrupt */ +}; + +static void sifive_spi_write(struct sifive_spi *spi, int offset, u32 value) +{ + iowrite32(value, spi->regs + offset); +} + +static u32 sifive_spi_read(struct sifive_spi *spi, int offset) +{ + return ioread32(spi->regs + offset); +} + +static void sifive_spi_init(struct sifive_spi *spi) +{ + /* Watermark interrupts are disabled by default */ + sifive_spi_write(spi, SIFIVE_SPI_REG_IE, 0); + + /* Default watermark FIFO threshold values */ + sifive_spi_write(spi, SIFIVE_SPI_REG_TXMARK, 1); + sifive_spi_write(spi, SIFIVE_SPI_REG_RXMARK, 0); + + /* Set CS/SCK Delays and Inactive Time to defaults */ + sifive_spi_write(spi, SIFIVE_SPI_REG_DELAY0, + SIFIVE_SPI_DELAY0_CSSCK(1) | + SIFIVE_SPI_DELAY0_SCKCS(1)); + sifive_spi_write(spi, SIFIVE_SPI_REG_DELAY1, + SIFIVE_SPI_DELAY1_INTERCS(1) | + SIFIVE_SPI_DELAY1_INTERXFR(0)); + + /* Exit specialized memory-mapped SPI flash mode */ + sifive_spi_write(spi, SIFIVE_SPI_REG_FCTRL, 0); +} + +static int +sifive_spi_prepare_message(struct spi_master *master, struct spi_message *msg) +{ + struct sifive_spi *spi = spi_master_get_devdata(master); + struct spi_device *device = msg->spi; + + /* Update the chip select polarity */ + if (device->mode & SPI_CS_HIGH) + spi->cs_inactive &= ~BIT(device->chip_select); + else + spi->cs_inactive |= BIT(device->chip_select); + sifive_spi_write(spi, SIFIVE_SPI_REG_CSDEF, spi->cs_inactive); + + /* Select the correct device */ + sifive_spi_write(spi, SIFIVE_SPI_REG_CSID, device->chip_select); + + /* Set clock mode */ + sifive_spi_write(spi, SIFIVE_SPI_REG_SCKMODE, + device->mode & SIFIVE_SPI_SCKMODE_MODE_MASK); + + return 0; +} + +static void sifive_spi_set_cs(struct spi_device *device, bool is_high) +{ + struct sifive_spi *spi = spi_master_get_devdata(device->master); + + /* Reverse polarity is handled by SCMR/CPOL. Not inverted CS. */ + if (device->mode & SPI_CS_HIGH) + is_high = !is_high; + + sifive_spi_write(spi, SIFIVE_SPI_REG_CSMODE, is_high ? + SIFIVE_SPI_CSMODE_MODE_AUTO : + SIFIVE_SPI_CSMODE_MODE_HOLD); +} + +static int +sifive_spi_prep_transfer(struct sifive_spi *spi, struct spi_device *device, + struct spi_transfer *t) +{ + u32 cr; + unsigned int mode; + + /* Calculate and program the clock rate */ + cr = DIV_ROUND_UP(clk_get_rate(spi->clk) >> 1, t->speed_hz) - 1; + cr &= SIFIVE_SPI_SCKDIV_DIV_MASK; + sifive_spi_write(spi, SIFIVE_SPI_REG_SCKDIV, cr); + + mode = max_t(unsigned int, t->rx_nbits, t->tx_nbits); + + /* Set frame format */ + cr = SIFIVE_SPI_FMT_LEN(t->bits_per_word); + switch (mode) { + case SPI_NBITS_QUAD: + cr |= SIFIVE_SPI_FMT_PROTO_QUAD; + break; + case SPI_NBITS_DUAL: + cr |= SIFIVE_SPI_FMT_PROTO_DUAL; + break; + default: + cr |= SIFIVE_SPI_FMT_PROTO_SINGLE; + break; + } + if (device->mode & SPI_LSB_FIRST) + cr |= SIFIVE_SPI_FMT_ENDIAN; + if (!t->rx_buf) + cr |= SIFIVE_SPI_FMT_DIR; + sifive_spi_write(spi, SIFIVE_SPI_REG_FMT, cr); + + /* We will want to poll if the time we need to wait is + * less than the context switching time. + * Let's call that threshold 5us. The operation will take: + * (8/mode) * fifo_depth / hz <= 5 * 10^-6 + * 1600000 * fifo_depth <= hz * mode + */ + return 1600000 * spi->fifo_depth <= t->speed_hz * mode; +} + +static irqreturn_t sifive_spi_irq(int irq, void *dev_id) +{ + struct sifive_spi *spi = dev_id; + u32 ip = sifive_spi_read(spi, SIFIVE_SPI_REG_IP); + + if (ip & (SIFIVE_SPI_IP_TXWM | SIFIVE_SPI_IP_RXWM)) { + /* Disable interrupts until next transfer */ + sifive_spi_write(spi, SIFIVE_SPI_REG_IE, 0); + complete(&spi->done); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static void sifive_spi_wait(struct sifive_spi *spi, u32 bit, int poll) +{ + if (poll) { + u32 cr; + + do { + cr = sifive_spi_read(spi, SIFIVE_SPI_REG_IP); + } while (!(cr & bit)); + } else { + reinit_completion(&spi->done); + sifive_spi_write(spi, SIFIVE_SPI_REG_IE, bit); + wait_for_completion(&spi->done); + } +} + +static void sifive_spi_tx(struct sifive_spi *spi, const u8 *tx_ptr) +{ + WARN_ON_ONCE((sifive_spi_read(spi, SIFIVE_SPI_REG_TXDATA) + & SIFIVE_SPI_TXDATA_FULL) != 0); + sifive_spi_write(spi, SIFIVE_SPI_REG_TXDATA, + *tx_ptr & SIFIVE_SPI_TXDATA_DATA_MASK); +} + +static void sifive_spi_rx(struct sifive_spi *spi, u8 *rx_ptr) +{ + u32 data = sifive_spi_read(spi, SIFIVE_SPI_REG_RXDATA); + + WARN_ON_ONCE((data & SIFIVE_SPI_RXDATA_EMPTY) != 0); + *rx_ptr = data & SIFIVE_SPI_RXDATA_DATA_MASK; +} + +static int +sifive_spi_transfer_one(struct spi_master *master, struct spi_device *device, + struct spi_transfer *t) +{ + struct sifive_spi *spi = spi_master_get_devdata(master); + int poll = sifive_spi_prep_transfer(spi, device, t); + const u8 *tx_ptr = t->tx_buf; + u8 *rx_ptr = t->rx_buf; + unsigned int remaining_words = t->len; + + while (remaining_words) { + unsigned int n_words = min(remaining_words, spi->fifo_depth); + unsigned int i; + + /* Enqueue n_words for transmission */ + for (i = 0; i < n_words; i++) + sifive_spi_tx(spi, tx_ptr++); + + if (rx_ptr) { + /* Wait for transmission + reception to complete */ + sifive_spi_write(spi, SIFIVE_SPI_REG_RXMARK, + n_words - 1); + sifive_spi_wait(spi, SIFIVE_SPI_IP_RXWM, poll); + + /* Read out all the data from the RX FIFO */ + for (i = 0; i < n_words; i++) + sifive_spi_rx(spi, rx_ptr++); + } else { + /* Wait for transmission to complete */ + sifive_spi_wait(spi, SIFIVE_SPI_IP_TXWM, poll); + } + + remaining_words -= n_words; + } + + return 0; +} + +static int sifive_spi_probe(struct platform_device *pdev) +{ + struct sifive_spi *spi; + struct resource *res; + int ret, irq, num_cs; + u32 cs_bits, max_bits_per_word; + struct spi_master *master; + + master = spi_alloc_master(&pdev->dev, sizeof(struct sifive_spi)); + if (!master) { + dev_err(&pdev->dev, "out of memory\n"); + return -ENOMEM; + } + + spi = spi_master_get_devdata(master); + init_completion(&spi->done); + platform_set_drvdata(pdev, master); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + spi->regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(spi->regs)) { + dev_err(&pdev->dev, "Unable to map IO resources\n"); + ret = PTR_ERR(spi->regs); + goto put_master; + } + + spi->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(spi->clk)) { + dev_err(&pdev->dev, "Unable to find bus clock\n"); + ret = PTR_ERR(spi->clk); + goto put_master; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "Unable to find interrupt\n"); + ret = irq; + goto put_master; + } + + /* Optional parameters */ + ret = + of_property_read_u32(pdev->dev.of_node, "sifive,fifo-depth", + &spi->fifo_depth); + if (ret < 0) + spi->fifo_depth = SIFIVE_SPI_DEFAULT_DEPTH; + + ret = + of_property_read_u32(pdev->dev.of_node, "sifive,max-bits-per-word", + &max_bits_per_word); + + if (!ret && max_bits_per_word < 8) { + dev_err(&pdev->dev, "Only 8bit SPI words supported by the driver\n"); + ret = -EINVAL; + goto put_master; + } + + /* Spin up the bus clock before hitting registers */ + ret = clk_prepare_enable(spi->clk); + if (ret) { + dev_err(&pdev->dev, "Unable to enable bus clock\n"); + goto put_master; + } + + /* probe the number of CS lines */ + spi->cs_inactive = sifive_spi_read(spi, SIFIVE_SPI_REG_CSDEF); + sifive_spi_write(spi, SIFIVE_SPI_REG_CSDEF, 0xffffffffU); + cs_bits = sifive_spi_read(spi, SIFIVE_SPI_REG_CSDEF); + sifive_spi_write(spi, SIFIVE_SPI_REG_CSDEF, spi->cs_inactive); + if (!cs_bits) { + dev_err(&pdev->dev, "Could not auto probe CS lines\n"); + ret = -EINVAL; + goto put_master; + } + + num_cs = ilog2(cs_bits) + 1; + if (num_cs > SIFIVE_SPI_MAX_CS) { + dev_err(&pdev->dev, "Invalid number of spi slaves\n"); + ret = -EINVAL; + goto put_master; + } + + /* Define our master */ + master->dev.of_node = pdev->dev.of_node; + master->bus_num = pdev->id; + master->num_chipselect = num_cs; + master->mode_bits = SPI_CPHA | SPI_CPOL + | SPI_CS_HIGH | SPI_LSB_FIRST + | SPI_TX_DUAL | SPI_TX_QUAD + | SPI_RX_DUAL | SPI_RX_QUAD; + /* TODO: add driver support for bits_per_word < 8 + * we need to "left-align" the bits (unless SPI_LSB_FIRST) + */ + master->bits_per_word_mask = SPI_BPW_MASK(8); + master->flags = SPI_CONTROLLER_MUST_TX | SPI_MASTER_GPIO_SS; + master->prepare_message = sifive_spi_prepare_message; + master->set_cs = sifive_spi_set_cs; + master->transfer_one = sifive_spi_transfer_one; + + pdev->dev.dma_mask = NULL; + /* Configure the SPI master hardware */ + sifive_spi_init(spi); + + /* Register for SPI Interrupt */ + ret = devm_request_irq(&pdev->dev, irq, sifive_spi_irq, 0, + dev_name(&pdev->dev), spi); + if (ret) { + dev_err(&pdev->dev, "Unable to bind to interrupt\n"); + goto put_master; + } + + dev_info(&pdev->dev, "mapped; irq=%d, cs=%d\n", + irq, master->num_chipselect); + + ret = devm_spi_register_master(&pdev->dev, master); + if (ret < 0) { + dev_err(&pdev->dev, "spi_register_master failed\n"); + goto put_master; + } + + return 0; + +put_master: + spi_master_put(master); + + return ret; +} + +static int sifive_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct sifive_spi *spi = spi_master_get_devdata(master); + + /* Disable all the interrupts just in case */ + sifive_spi_write(spi, SIFIVE_SPI_REG_IE, 0); + spi_master_put(master); + + return 0; +} + +static const struct of_device_id sifive_spi_of_match[] = { + { .compatible = "sifive,spi0", }, + {} +}; +MODULE_DEVICE_TABLE(of, sifive_spi_of_match); + +static struct platform_driver sifive_spi_driver = { + .probe = sifive_spi_probe, + .remove = sifive_spi_remove, + .driver = { + .name = SIFIVE_SPI_DRIVER_NAME, + .of_match_table = sifive_spi_of_match, + }, +}; +module_platform_driver(sifive_spi_driver); + +MODULE_AUTHOR("SiFive, Inc. "); +MODULE_DESCRIPTION("SiFive SPI driver"); +MODULE_LICENSE("GPL");