From: Armando Visconti armando.visconti@st.com
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 --- drivers/spi/Makefile | 1 + drivers/spi/pl022_spi.c | 310 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 311 insertions(+) create mode 100644 drivers/spi/pl022_spi.c
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 824d357..3a4e4b0 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -42,6 +42,7 @@ 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..ba018b8 --- /dev/null +++ b/drivers/spi/pl022_spi.c @@ -0,0 +1,310 @@ +/* + * (C) Copyright 2012 + * Armando Visconti, ST Microelectronics, armando.visconti@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 + */ + +#include <common.h> +#include <malloc.h> +#include <spi.h> +#include <asm/io.h> +#include <asm/arch/hardware.h> + +/* SSP registers mapping */ +struct pl022 { + 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 */ +}; + +/* 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 */ + +struct pl022_spi_slave { + struct spi_slave slave; + void *regs; + 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() +{ + /* 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 ((readw(pl022->ssp_pid0) == 0x22) && + (readw(pl022->ssp_pid1) == 0x10) && + ((readw(pl022->ssp_pid2) & 0xf) == 0x04) && + (readw(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 = malloc(sizeof(*ps)); + if (!ps) + return NULL; + + ps->slave.bus = bus; + ps->slave.cs = cs; + 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; + + writew(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++; + + writew(cpsr, pl022->ssp_cpsr); + cr0 = readw(pl022->ssp_cr0); + writew(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_le16(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 */ + writew(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 (readw(pl022->ssp_sr) & SSP_SR_MASK_TNF) { + value = (txp != NULL) ? *txp++ : 0; + writew(value, pl022->ssp_dr); + len_tx++; + } + + if (readw(pl022->ssp_sr) & SSP_SR_MASK_RNE) { + value = readw(pl022->ssp_dr); + if (rxp) + *rxp++ = value; + len_rx++; + } + } + + while (len_rx < len_tx) { + if (readw(pl022->ssp_sr) & SSP_SR_MASK_RNE) { + value = readw(pl022->ssp_dr); + if (rxp) + *rxp++ = value; + len_rx++; + } + } + +out: + if (flags & SPI_XFER_END) + spi_cs_deactivate(slave); + + return ret; +}