[U-Boot] [PATCH v6] spi: pl022_spi: Add support for ARM PL022 spi controller

Jagan Teki
2013-10-04T06:50:11Z

Hi Vipin,

I have few quick comments, please fix it.
Please use the u-boot-spi.git with master-probe branch for testing this driver.
Let me know for any issues/concerns.

On Wed, Jun 12, 2013 at 7:55 PM, Jagan Teki <jagannadh.teki@gmail.com> wrote:
> Thanks for v6 sent.
>
> Have you tested this?
> on which board, include/configs/*.h file?
>
> --
> Thanks,
> Jagan.
>
> On Wed, Jun 12, 2013 at 6:17 PM, Armando Visconti
> <armando.visconti@st.com> wrote:
>> This patch adds the support for the ARM PL022 SPI controller for the standard
>> variant (0x00041022), which has a 16bit wide and 8 locations deep TX/RX FIFO.
>>
>> Signed-off-by: Armando Visconti <armando.visconti@st.com>
>> Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
>> Acked-by: Stefan Roese <sr@denx.de>
>> ---
>> v5->v6
>>
>> 1. Make use of spi_alloc_slave() macro.
>> 2. Changed the identation on 'if statement' as requested
>> by Jagan.
>>
>> drivers/spi/Makefile | 1 +
>> drivers/spi/pl022_spi.c | 308 ++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 309 insertions(+)
>> create mode 100644 drivers/spi/pl022_spi.c
>>
>> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>> index d08609e..b6443b1 100644
>> --- a/drivers/spi/Makefile
>> +++ b/drivers/spi/Makefile
>> @@ -47,6 +47,7 @@ COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
>> COBJS-$(CONFIG_MXS_SPI) += mxs_spi.o
>> COBJS-$(CONFIG_OC_TINY_SPI) += oc_tiny_spi.o
>> COBJS-$(CONFIG_OMAP3_SPI) += omap3_spi.o
>> +COBJS-$(CONFIG_PL022_SPI) += pl022_spi.o
>> COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
>> COBJS-$(CONFIG_SH_SPI) += sh_spi.o
>> COBJS-$(CONFIG_FSL_ESPI) += fsl_espi.o
>> diff --git a/drivers/spi/pl022_spi.c b/drivers/spi/pl022_spi.c
>> new file mode 100644
>> index 0000000..5b47413
>> --- /dev/null
>> +++ b/drivers/spi/pl022_spi.c
>> @@ -0,0 +1,308 @@
>> +/*
>> + * (C) Copyright 2012
>> + * Armando Visconti, ST Microelectronics, armando.visconti at st.com.
>> + *
>> + * Driver for ARM PL022 SPI Controller. Based on atmel_spi.c
>> + * by Atmel Corporation.
>> + *
>> + * 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.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
>> + * MA 02111-1307 USA
>> + */
Use latest SPDX-License-Identifier:
check for any existing one.

>> +
>> +#include <common.h>
>> +#include <malloc.h>
>> +#include <spi.h>
>> +#include <asm/io.h>
>> +#include <asm/arch/hardware.h>
>> +
>> +/* SSP registers mapping */
>> +struct pl022 {
Something like pl022_spi_regs

>> + u32 ssp_cr0; /* 0x000 */
>> + u32 ssp_cr1; /* 0x004 */
>> + u32 ssp_dr; /* 0x008 */
>> + u32 ssp_sr; /* 0x00c */
>> + u32 ssp_cpsr; /* 0x010 */
>> + u32 ssp_imsc; /* 0x014 */
>> + u32 ssp_ris; /* 0x018 */
>> + u32 ssp_mis; /* 0x01c */
>> + u32 ssp_icr; /* 0x020 */
>> + u32 ssp_dmacr; /* 0x024 */
>> + u8 reserved_1[0x080 - 0x028];
>> + u32 ssp_itcr; /* 0x080 */
>> + u32 ssp_itip; /* 0x084 */
>> + u32 ssp_itop; /* 0x088 */
>> + u32 ssp_tdr; /* 0x08c */
>> + u8 reserved_2[0xFE0 - 0x090];
>> + u32 ssp_pid0; /* 0xfe0 */
>> + u32 ssp_pid1; /* 0xfe4 */
>> + u32 ssp_pid2; /* 0xfe8 */
>> + u32 ssp_pid3; /* 0xfec */
>> + u32 ssp_cid0; /* 0xff0 */
>> + u32 ssp_cid1; /* 0xff4 */
>> + u32 ssp_cid2; /* 0xff8 */
>> + u32 ssp_cid3; /* 0xffc */
>> +};
>> +

-- TAG+
>> +/* SSP Control Register 0 - SSP_CR0 */
>> +#define SSP_CR0_SPO (0x1 << 6)
>> +#define SSP_CR0_SPH (0x1 << 7)
>> +#define SSP_CR0_8BIT_MODE (0x07)
>> +#define SSP_SCR_MAX (0xFF)
>> +#define SSP_SCR_SHFT 8
>> +
>> +/* SSP Control Register 0 - SSP_CR1 */
>> +#define SSP_CR1_MASK_SSE (0x1 << 1)
>> +
>> +#define SSP_CPSR_MAX (0xFE)
>> +
>> +/* SSP Status Register - SSP_SR */
>> +#define SSP_SR_MASK_TFE (0x1 << 0) /* Transmit FIFO empty */
>> +#define SSP_SR_MASK_TNF (0x1 << 1) /* Transmit FIFO not full */
>> +#define SSP_SR_MASK_RNE (0x1 << 2) /* Receive FIFO not empty */
>> +#define SSP_SR_MASK_RFF (0x1 << 3) /* Receive FIFO full */
>> +#define SSP_SR_MASK_BSY (0x1 << 4) /* Busy Flag */
>> +
--- TAG -

Bit mask macros - please place after headers.
We follow a simple format to write spi driver - please check
http://patchwork.ozlabs.org/patch/265683/

And try to verify your code w.r.t above format - let me know any comments.

>> +struct pl022_spi_slave {
>> + struct spi_slave slave;
>> + void *regs;

Please use the structure pointer instead of void.

>> + unsigned int freq;
>> +};
>> +
>> +static inline struct pl022_spi_slave *to_pl022_spi(struct spi_slave *slave)
>> +{
>> + return container_of(slave, struct pl022_spi_slave, slave);
>> +}
>> +
>> +/*
>> + * Following three functions should be provided by the
>> + * board support package.
>> + */
>> +int __weak spi_cs_is_valid(unsigned int bus, unsigned int cs)
>> +{
>> + return 1;
>> +}
>> +
>> +void __weak spi_cs_activate(struct spi_slave *slave)
>> +{
>> + /* do nothing */
>> +}
>> +
>> +void __weak spi_cs_deactivate(struct spi_slave *slave)
>> +{
>> + /* do nothing */
>> +}
>> +
>> +void spi_init(void)
>> +{
>> + /* do nothing */
>> +}
>> +
>> +/*
>> + * ARM PL022 exists in different 'flavors'.
>> + * This drivers currently support the standard variant (0x00041022), that has a
>> + * 16bit wide and 8 locations deep TX/RX FIFO.
>> + */
>> +static int pl022_is_supported(struct pl022_spi_slave *ps)
>> +{
>> + struct pl022 *pl022 = (struct pl022 *)ps->regs;
>> +
>> + /* PL022 version is 0x00041022 */
>> + if ((readl(&pl022->ssp_pid0) == 0x22) &&
>> + (readl(&pl022->ssp_pid1) == 0x10) &&
>> + ((readl(&pl022->ssp_pid2) & 0xf) == 0x04) &&
>> + (readl(&pl022->ssp_pid3) == 0x00))
>> + return 1;
>> +
>> + return 0;
>> +}
>> +
>> +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
>> + unsigned int max_hz, unsigned int mode)
>> +{
>> + struct pl022_spi_slave *ps;
>> + struct pl022 *pl022;
>> + u16 scr = 1, prescaler, cr0 = 0, cpsr = 0;
>> +
>> + if (!spi_cs_is_valid(bus, cs))
>> + return NULL;
>> +
>> + ps = spi_alloc_slave(struct pl022_spi_slave, bus, cs);
>> + if (!ps)
>> + return NULL;
>> +
>> + ps->freq = max_hz;
>> +
>> + switch (bus) {
>> + case 0:
>> + ps->regs = (void *)CONFIG_SYS_SPI_BASE;
>> + break;
>> +#ifdef CONFIG_SYS_SPI_BASE1
>> + case 1:
>> + ps->regs = (void *)CONFIG_SYS_SPI_BASE1;
>> + break;
>> +#endif
>> +#ifdef CONFIG_SYS_SPI_BASE2
>> + case 2:
>> + ps->regs = (void *)CONFIG_SYS_SPI_BASE2;
>> + break;
>> +#endif
>> +#ifdef CONFIG_SYS_SPI_BASE3
>> + case 3:
>> + ps->regs = (void *)CONFIG_SYS_SPI_BASE3;
>> + break;
>> +#endif
>> + default:
>> + free(ps);
>> + return NULL;
>> + }
>> +
>> + pl022 = (struct pl022 *)ps->regs;
>> +
>> + /* Check the PL022 version */
>> + if (!pl022_is_supported(ps)) {
>> + free(ps);
>> + return NULL;
>> + }
>> +
>> + /* Set requested polarity and 8bit mode */
>> + cr0 = SSP_CR0_8BIT_MODE;
>> + cr0 |= (mode & SPI_CPHA) ? SSP_CR0_SPH : 0;
>> + cr0 |= (mode & SPI_CPOL) ? SSP_CR0_SPO : 0;
>> +
>> + writel(cr0, &pl022->ssp_cr0);
>> +
>> + /* Program the SSPClk frequency */
>> + prescaler = CONFIG_SYS_SPI_CLK / ps->freq;
>> +
>> + if (prescaler <= 0xFF) {
>> + cpsr = prescaler;
>> + } else {
>> + for (scr = 1; scr <= SSP_SCR_MAX; scr++) {
>> + if (!(prescaler % scr)) {
>> + cpsr = prescaler / scr;
>> + if (cpsr <= SSP_CPSR_MAX)
>> + break;
>> + }
>> + }
>> +
>> + if (scr > SSP_SCR_MAX) {
>> + scr = SSP_SCR_MAX;
>> + cpsr = prescaler / scr;
>> + cpsr &= SSP_CPSR_MAX;
>> + }
>> + }
>> +
>> + if (cpsr & 0x1)
>> + cpsr++;
>> +
>> + writel(cpsr, &pl022->ssp_cpsr);
>> + cr0 = readl(&pl022->ssp_cr0);
>> + writel(cr0 | (scr - 1) << SSP_SCR_SHFT, &pl022->ssp_cr0);
>> +
>> + return &ps->slave;
>> +}
>> +
>> +void spi_free_slave(struct spi_slave *slave)
>> +{
>> + struct pl022_spi_slave *ps = to_pl022_spi(slave);
>> +
>> + free(ps);
>> +}
>> +
>> +int spi_claim_bus(struct spi_slave *slave)
>> +{
>> + struct pl022_spi_slave *ps = to_pl022_spi(slave);
>> + struct pl022 *pl022 = (struct pl022 *)ps->regs;
>> +
>> + /* Enable the SPI hardware */
>> + setbits_le32(&pl022->ssp_cr1, SSP_CR1_MASK_SSE);
>> +
>> + return 0;
>> +}
>> +
>> +void spi_release_bus(struct spi_slave *slave)
>> +{
>> + struct pl022_spi_slave *ps = to_pl022_spi(slave);
>> + struct pl022 *pl022 = (struct pl022 *)ps->regs;
>> +
>> + /* Disable the SPI hardware */
>> + writel(0x0, &pl022->ssp_cr1);
>> +}
>> +
>> +int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
>> + const void *dout, void *din, unsigned long flags)
>> +{
>> + struct pl022_spi_slave *ps = to_pl022_spi(slave);
>> + struct pl022 *pl022 = (struct pl022 *)ps->regs;
>> + u32 len_tx = 0, len_rx = 0, len;
>> + u32 ret = 0;
>> + const u8 *txp = dout;
>> + u8 *rxp = din, value;
>> +
>> + if (bitlen == 0)
>> + /* Finish any previously submitted transfers */
>> + goto out;
>> +
>> + /*
>> + * TODO: The controller can do non-multiple-of-8 bit
>> + * transfers, but this driver currently doesn't support it.
>> + *
>> + * It's also not clear how such transfers are supposed to be
>> + * represented as a stream of bytes...this is a limitation of
>> + * the current SPI interface.
>> + */
>> + if (bitlen % 8) {
>> + ret = -1;
>> +
>> + /* Errors always terminate an ongoing transfer */
>> + flags |= SPI_XFER_END;
>> + goto out;
>> + }
>> +
>> + len = bitlen / 8;
>> +
>> + if (flags & SPI_XFER_BEGIN)
>> + spi_cs_activate(slave);
>> +
>> + while (len_tx < len) {
>> + if (readl(&pl022->ssp_sr) & SSP_SR_MASK_TNF) {
>> + value = (txp != NULL) ? *txp++ : 0;
>> + writel(value, &pl022->ssp_dr);
>> + len_tx++;
>> + }
>> +
>> + if (readl(&pl022->ssp_sr) & SSP_SR_MASK_RNE) {
>> + value = readl(&pl022->ssp_dr);
>> + if (rxp)
>> + *rxp++ = value;
>> + len_rx++;
>> + }
>> + }
>> +
>> + while (len_rx < len_tx) {
>> + if (readl(&pl022->ssp_sr) & SSP_SR_MASK_RNE) {
>> + value = readl(&pl022->ssp_dr);
>> + if (rxp)
>> + *rxp++ = value;
>> + len_rx++;
>> + }
>> + }
>> +
>> +out:
>> + if (flags & SPI_XFER_END)
>> + spi_cs_deactivate(slave);
>> +
>> + return ret;
>> +}
>> --
>> 1.7.11.7
>>

--
Thanks,
Jagan.
--------
Jagannadha Sutradharudu Teki,
E: jagannadh.teki at gmail.com, P: +91-9676773388
Engineer - System Software Hacker
U-boot - SPI Custodian and Zynq APSOC
Ln: http://www.linkedin.com/in/jaganteki