[U-Boot] [PATCH v2 1/3] spi: add support for ARM PL022 SPI controller
Quentin Schulz
quentin.schulz at bootlin.com
Fri Aug 31 14:28:29 UTC 2018
This adds support for the ARM PL022 SPI controller for the standard
variant (0x00041022) which has a 16bit wide and 8 locations deep TX/RX
FIFO.
A few parts were borrowed from the Linux kernel driver.
Cc: Armando Visconti <armando.visconti at st.com>
Cc: Vipin Kumar <vipin.kumar at st.com>
Signed-off-by: Quentin Schulz <quentin.schulz at bootlin.com>
---
v2:
- move header file to include/dm/platform_data,
- replace REGA(x) by x + REGA,
- surround DT specific code with #define !defined(CONFIG_OF_PLATDATA),
- fix tmp speed being stored in a u16 which overflowed and returned the
minimum possible rate,
- fix speed computation to be the closest to the requested value, not
only the closest *below* this value,
- init best_* values so that they can safely be used even if no best
value is found,
- flush FIFO RX queue after the controller is enabled makes more sense
to me,
drivers/spi/Kconfig | 8 +-
drivers/spi/Makefile | 1 +-
drivers/spi/pl022_spi.c | 338 ++++++++++++++++++++++++++++-
include/dm/platform_data/pl022_spi.h | 28 ++-
4 files changed, 375 insertions(+)
create mode 100644 drivers/spi/pl022_spi.c
create mode 100644 include/dm/platform_data/pl022_spi.h
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index dcd719f..7d4d47d 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -125,6 +125,14 @@ config PIC32_SPI
to access the SPI NOR flash, MMC-over-SPI on platforms based on
Microchip PIC32 family devices.
+config PL022_SPI
+ bool "ARM AMBA PL022 SSP controller driver"
+ depends on ARM
+ help
+ This selects the ARM(R) AMBA(R) PrimeCell PL022 SSP
+ controller. If you have an embedded system with an AMBA(R)
+ bus and a PL022 controller, say Y or M here.
+
config RENESAS_RPC_SPI
bool "Renesas RPC SPI driver"
depends on RCAR_GEN3
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 728e30c..6679987 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_MXS_SPI) += mxs_spi.o
obj-$(CONFIG_ATCSPI200_SPI) += atcspi200_spi.o
obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
obj-$(CONFIG_PIC32_SPI) += pic32_spi.o
+obj-$(CONFIG_PL022_SPI) += pl022_spi.o
obj-$(CONFIG_RENESAS_RPC_SPI) += renesas_rpc_spi.o
obj-$(CONFIG_ROCKCHIP_SPI) += rk_spi.o
obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
diff --git a/drivers/spi/pl022_spi.c b/drivers/spi/pl022_spi.c
new file mode 100644
index 0000000..86b71d2
--- /dev/null
+++ b/drivers/spi/pl022_spi.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2012
+ * Armando Visconti, ST Microelectronics, armando.visconti at st.com.
+ *
+ * (C) Copyright 2018
+ * Quentin Schulz, Bootlin, quentin.schulz at bootlin.com
+ *
+ * Driver for ARM PL022 SPI Controller.
+ */
+
+#include <asm/io.h>
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/platform_data/pl022_spi.h>
+#include <fdtdec.h>
+#include <linux/bitops.h>
+#include <linux/bug.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <spi.h>
+
+#define SSP_CR0 0x000
+#define SSP_CR1 0x004
+#define SSP_DR 0x008
+#define SSP_SR 0x00C
+#define SSP_CPSR 0x010
+#define SSP_IMSC 0x014
+#define SSP_RIS 0x018
+#define SSP_MIS 0x01C
+#define SSP_ICR 0x020
+#define SSP_DMACR 0x024
+#define SSP_CSR 0x030 /* vendor extension */
+#define SSP_ITCR 0x080
+#define SSP_ITIP 0x084
+#define SSP_ITOP 0x088
+#define SSP_TDR 0x08C
+
+#define SSP_PID0 0xFE0
+#define SSP_PID1 0xFE4
+#define SSP_PID2 0xFE8
+#define SSP_PID3 0xFEC
+
+#define SSP_CID0 0xFF0
+#define SSP_CID1 0xFF4
+#define SSP_CID2 0xFF8
+#define SSP_CID3 0xFFC
+
+/* SSP Control Register 0 - SSP_CR0 */
+#define SSP_CR0_SPO (0x1 << 6)
+#define SSP_CR0_SPH (0x1 << 7)
+#define SSP_CR0_BIT_MODE(x) ((x) - 1)
+#define SSP_SCR_MIN (0x00)
+#define SSP_SCR_MAX (0xFF)
+#define SSP_SCR_SHFT 8
+#define DFLT_CLKRATE 2
+
+/* SSP Control Register 1 - SSP_CR1 */
+#define SSP_CR1_MASK_SSE (0x1 << 1)
+
+#define SSP_CPSR_MIN (0x02)
+#define SSP_CPSR_MAX (0xFE)
+#define DFLT_PRESCALE (0x40)
+
+/* 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 {
+ void *base;
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ struct clk clk;
+#else
+ unsigned int freq;
+#endif
+};
+
+/*
+ * 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)
+{
+ /* PL022 version is 0x00041022 */
+ if ((readw(ps->base + SSP_PID0) == 0x22) &&
+ (readw(ps->base + SSP_PID1) == 0x10) &&
+ ((readw(ps->base + SSP_PID2) & 0xf) == 0x04) &&
+ (readw(ps->base + SSP_PID3) == 0x00))
+ return 1;
+
+ return 0;
+}
+
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+static int pl022_spi_ofdata_to_platdata(struct udevice *bus)
+{
+ struct pl022_spi_pdata *plat = bus->platdata;
+ const void *fdt = gd->fdt_blob;
+ int node = dev_of_offset(bus);
+
+ plat->addr = fdtdec_get_addr_size(fdt, node, "reg", &plat->size);
+
+ return clk_get_by_index(bus, 0, &plat->clk);
+}
+#endif
+
+static int pl022_spi_probe(struct udevice *bus)
+{
+ struct pl022_spi_pdata *plat = dev_get_platdata(bus);
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+
+ ps->base = ioremap(plat->addr, plat->size);
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ ps->clk = plat->clk;
+#else
+ ps->freq = plat->freq;
+#endif
+
+ /* Check the PL022 version */
+ if (!pl022_is_supported(ps))
+ return -ENOTSUPP;
+
+ /* 8 bits per word, high polarity and default clock rate */
+ writew(SSP_CR0_BIT_MODE(8), ps->base + SSP_CR0);
+ writew(DFLT_PRESCALE, ps->base + SSP_CPSR);
+
+ return 0;
+}
+
+static void flush(struct pl022_spi_slave *ps)
+{
+ do {
+ while (readw(ps->base + SSP_SR) & SSP_SR_MASK_RNE)
+ readw(ps->base + SSP_DR);
+ } while (readw(ps->base + SSP_SR) & SSP_SR_MASK_BSY);
+}
+
+static int pl022_spi_claim_bus(struct udevice *dev)
+{
+ struct udevice *bus = dev->parent;
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+ u16 reg;
+
+ /* Enable the SPI hardware */
+ reg = readw(ps->base + SSP_CR1);
+ reg |= SSP_CR1_MASK_SSE;
+ writew(reg, ps->base + SSP_CR1);
+
+ flush(ps);
+
+ return 0;
+}
+
+static int pl022_spi_release_bus(struct udevice *dev)
+{
+ struct udevice *bus = dev->parent;
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+ u16 reg;
+
+ flush(ps);
+
+ /* Disable the SPI hardware */
+ reg = readw(ps->base + SSP_CR1);
+ reg &= ~SSP_CR1_MASK_SSE;
+ writew(reg, ps->base + SSP_CR1);
+
+ return 0;
+}
+
+static int pl022_spi_xfer(struct udevice *dev, unsigned int bitlen,
+ const void *dout, void *din, unsigned long flags)
+{
+ struct udevice *bus = dev->parent;
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+ 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 */
+ return 0;
+
+ /*
+ * 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) {
+ /* Errors always terminate an ongoing transfer */
+ flags |= SPI_XFER_END;
+ return -1;
+ }
+
+ len = bitlen / 8;
+
+ while (len_tx < len) {
+ if (readw(ps->base + SSP_SR) & SSP_SR_MASK_TNF) {
+ value = txp ? *txp++ : 0;
+ writew(value, ps->base + SSP_DR);
+ len_tx++;
+ }
+
+ if (readw(ps->base + SSP_SR) & SSP_SR_MASK_RNE) {
+ value = readw(ps->base + SSP_DR);
+ if (rxp)
+ *rxp++ = value;
+ len_rx++;
+ }
+ }
+
+ while (len_rx < len_tx) {
+ if (readw(ps->base + SSP_SR) & SSP_SR_MASK_RNE) {
+ value = readw(ps->base + SSP_DR);
+ if (rxp)
+ *rxp++ = value;
+ len_rx++;
+ }
+ }
+
+ return ret;
+}
+
+static inline u32 spi_rate(u32 rate, u16 cpsdvsr, u16 scr)
+{
+ return rate / (cpsdvsr * (1 + scr));
+}
+
+static int pl022_spi_set_speed(struct udevice *bus, uint speed)
+{
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+ u16 scr = SSP_SCR_MIN, cr0 = 0, cpsr = SSP_CPSR_MIN, best_scr = scr,
+ best_cpsr = cpsr;
+ u32 min, max, best_freq = 0, tmp;
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ u32 rate = clk_get_rate(&ps->clk);
+#else
+ u32 rate = ps->freq;
+#endif
+ bool found = false;
+
+ max = spi_rate(rate, SSP_CPSR_MIN, SSP_SCR_MIN);
+ min = spi_rate(rate, SSP_CPSR_MAX, SSP_SCR_MAX);
+
+ if (speed > max || speed < min) {
+ pr_err("Tried to set speed to %dHz but min=%d and max=%d\n",
+ speed, min, max);
+ return -EINVAL;
+ }
+
+ while (cpsr <= SSP_CPSR_MAX && !found) {
+ while (scr <= SSP_SCR_MAX) {
+ tmp = spi_rate(rate, cpsr, scr);
+
+ if (abs(speed - tmp) < abs(speed - best_freq)) {
+ best_freq = tmp;
+ best_cpsr = cpsr;
+ best_scr = scr;
+
+ if (tmp == speed) {
+ found = true;
+ break;
+ }
+ }
+
+ scr++;
+ }
+ cpsr += 2;
+ scr = SSP_SCR_MIN;
+ }
+
+ writew(best_cpsr, ps->base + SSP_CPSR);
+ cr0 = readw(ps->base + SSP_CR0);
+ writew(cr0 | (best_scr << SSP_SCR_SHFT), ps->base + SSP_CR0);
+
+ return 0;
+}
+
+static int pl022_spi_set_mode(struct udevice *bus, uint mode)
+{
+ struct pl022_spi_slave *ps = dev_get_priv(bus);
+ u16 reg;
+
+ reg = readw(ps->base + SSP_CR0);
+ reg &= ~(SSP_CR0_SPH | SSP_CR0_SPO);
+ if (mode & SPI_CPHA)
+ reg |= SSP_CR0_SPH;
+ if (mode & SPI_CPOL)
+ reg |= SSP_CR0_SPO;
+ writew(reg, ps->base + SSP_CR0);
+
+ return 0;
+}
+
+static int pl022_cs_info(struct udevice *bus, uint cs,
+ struct spi_cs_info *info)
+{
+ return 0;
+}
+
+static const struct dm_spi_ops pl022_spi_ops = {
+ .claim_bus = pl022_spi_claim_bus,
+ .release_bus = pl022_spi_release_bus,
+ .xfer = pl022_spi_xfer,
+ .set_speed = pl022_spi_set_speed,
+ .set_mode = pl022_spi_set_mode,
+ .cs_info = pl022_cs_info,
+};
+
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+static const struct udevice_id pl022_spi_ids[] = {
+ { .compatible = "arm,pl022-spi" },
+ { }
+};
+#endif
+
+U_BOOT_DRIVER(pl022_spi) = {
+ .name = "pl022_spi",
+ .id = UCLASS_SPI,
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ .of_match = pl022_spi_ids,
+#endif
+ .ops = &pl022_spi_ops,
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ .ofdata_to_platdata = pl022_spi_ofdata_to_platdata,
+#endif
+ .platdata_auto_alloc_size = sizeof(struct pl022_spi_pdata),
+ .priv_auto_alloc_size = sizeof(struct pl022_spi_slave),
+ .probe = pl022_spi_probe,
+};
diff --git a/include/dm/platform_data/pl022_spi.h b/include/dm/platform_data/pl022_spi.h
new file mode 100644
index 0000000..77fe6da
--- /dev/null
+++ b/include/dm/platform_data/pl022_spi.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2018
+ * Quentin Schulz, Bootlin, quentin.schulz at bootlin.com
+ *
+ * Structure for use with U_BOOT_DEVICE for pl022 SPI devices or to use
+ * in ofdata_to_platdata.
+ */
+
+#ifndef __PL022_SPI_H__
+#define __PL022_SPI_H__
+
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+#include <clk.h>
+#endif
+#include <fdtdec.h>
+
+struct pl022_spi_pdata {
+ fdt_addr_t addr;
+ fdt_size_t size;
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+ struct clk clk;
+#else
+ unsigned int freq;
+#endif
+};
+
+#endif
base-commit: b3e29c65aa7bda80cba063433878ebfcd3bb7601
--
git-series 0.9.1
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