[PATCH v5 4/6] spi: sh-msiof: Add slave mode support

From: Geert Uytterhoeven
Date: Mon May 22 2017 - 09:12:37 EST

From: Hisashi Nakamura <hisashi.nakamura.ak@xxxxxxxxxxx>

Add slave mode support to the MSIOF driver, in both PIO and DMA mode.

For now this only supports the transmission of messages with a size
that is known in advance.

Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@xxxxxxxxxxx>
Signed-off-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@xxxxxxxxxxx>
[geert: Timeout handling cleanup, spi core integration, cancellation,
rewording]
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
---
v5:
- No changes,

v4:
- Add Acked-by,
- Use slave_aborted flag and complete() instead of messing with
internal completion and thread state,

v3:
- Clear TIF_SIGPENDING when interrupted to fix cancellation,
- Extract sh_msiof_wait_for_completion(),
- Add #include <linux/sched/signal.h>,
- Convert to use spi_alloc_slave(),

v2:
- Document "spi-slave" property in DT bindings,
- Use spi_controller_is_slave() helper,
- Check for "spi-slave" property instead of "slave" child node,
- Replace SPI_MASTER_IS_SLAVE by SPI_CONTROLLER_IS_SLAVE,
- Implement cancellation.
---
Documentation/devicetree/bindings/spi/sh-msiof.txt | 2 +
drivers/spi/spi-sh-msiof.c | 111 +++++++++++++++------
include/linux/spi/sh_msiof.h | 6 ++
3 files changed, 86 insertions(+), 33 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/sh-msiof.txt b/Documentation/devicetree/bindings/spi/sh-msiof.txt
index dc975064fa273c36..64ee489571c42f88 100644
--- a/Documentation/devicetree/bindings/spi/sh-msiof.txt
+++ b/Documentation/devicetree/bindings/spi/sh-msiof.txt
@@ -38,6 +38,8 @@ Optional properties:
specifiers, one for transmission, and one for
reception.
- dma-names : Must contain a list of two DMA names, "tx" and "rx".
+- spi-slave : Empty property indicating the SPI controller is used
+ in slave mode.
- renesas,dtdl : delay sync signal (setup) in transmit mode.
Must contain one of the following values:
0 (no bit delay)
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index 2ce15ca977828668..c304c7167866d2db 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -2,7 +2,8 @@
* SuperH MSIOF SPI Master Interface
*
* Copyright (c) 2009 Magnus Damm
- * Copyright (C) 2014 Glider bvba
+ * Copyright (C) 2014 Renesas Electronics Corporation
+ * Copyright (C) 2014-2017 Glider bvba
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -33,7 +34,6 @@

#include <asm/unaligned.h>

-
struct sh_msiof_chipdata {
u16 tx_fifo_size;
u16 rx_fifo_size;
@@ -53,6 +53,7 @@ struct sh_msiof_spi_priv {
void *rx_dma_page;
dma_addr_t tx_dma_addr;
dma_addr_t rx_dma_addr;
+ bool slave_aborted;
};

#define TMDR1 0x00 /* Transmit Mode Register 1 */
@@ -337,7 +338,10 @@ static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
tmp |= !cs_high << MDR1_SYNCAC_SHIFT;
tmp |= lsb_first << MDR1_BITLSB_SHIFT;
tmp |= sh_msiof_spi_get_dtdl_and_syncdl(p);
- sh_msiof_write(p, TMDR1, tmp | MDR1_TRMD | TMDR1_PCON);
+ if (spi_controller_is_slave(p->master))
+ sh_msiof_write(p, TMDR1, tmp | TMDR1_PCON);
+ else
+ sh_msiof_write(p, TMDR1, tmp | MDR1_TRMD | TMDR1_PCON);
if (p->master->flags & SPI_MASTER_MUST_TX) {
/* These bits are reserved if RX needs TX */
tmp &= ~0x0000ffff;
@@ -564,17 +568,19 @@ static int sh_msiof_prepare_message(struct spi_master *master,

static int sh_msiof_spi_start(struct sh_msiof_spi_priv *p, void *rx_buf)
{
- int ret;
+ bool slave = spi_controller_is_slave(p->master);
+ int ret = 0;

/* setup clock and rx/tx signals */
- ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
+ if (!slave)
+ ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
if (rx_buf && !ret)
ret = sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
if (!ret)
ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);

/* start by setting frame bit */
- if (!ret)
+ if (!ret && !slave)
ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);

return ret;
@@ -582,20 +588,49 @@ static int sh_msiof_spi_start(struct sh_msiof_spi_priv *p, void *rx_buf)

static int sh_msiof_spi_stop(struct sh_msiof_spi_priv *p, void *rx_buf)
{
- int ret;
+ bool slave = spi_controller_is_slave(p->master);
+ int ret = 0;

/* shut down frame, rx/tx and clock signals */
- ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
+ if (!slave)
+ ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
if (!ret)
ret = sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
if (rx_buf && !ret)
ret = sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
- if (!ret)
+ if (!ret && !slave)
ret = sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);

return ret;
}

+static int sh_msiof_slave_abort(struct spi_master *master)
+{
+ struct sh_msiof_spi_priv *p = spi_master_get_devdata(master);
+
+ p->slave_aborted = true;
+ complete(&p->done);
+ return 0;
+}
+
+static int sh_msiof_wait_for_completion(struct sh_msiof_spi_priv *p)
+{
+ if (spi_controller_is_slave(p->master)) {
+ if (wait_for_completion_interruptible(&p->done) ||
+ p->slave_aborted) {
+ dev_dbg(&p->pdev->dev, "interrupted\n");
+ return -EINTR;
+ }
+ } else {
+ if (!wait_for_completion_timeout(&p->done, HZ)) {
+ dev_err(&p->pdev->dev, "timeout\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ return 0;
+}
+
static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
void (*tx_fifo)(struct sh_msiof_spi_priv *,
const void *, int, int),
@@ -628,6 +663,7 @@ static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
tx_fifo(p, tx_buf, words, fifo_shift);

reinit_completion(&p->done);
+ p->slave_aborted = false;

ret = sh_msiof_spi_start(p, rx_buf);
if (ret) {
@@ -636,11 +672,9 @@ static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
}

/* wait for tx fifo to be emptied / rx fifo to be filled */
- if (!wait_for_completion_timeout(&p->done, HZ)) {
- dev_err(&p->pdev->dev, "PIO timeout\n");
- ret = -ETIMEDOUT;
+ ret = sh_msiof_wait_for_completion(p);
+ if (ret)
goto stop_reset;
- }

/* read rx fifo */
if (rx_buf)
@@ -732,6 +766,7 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
sh_msiof_write(p, IER, ier_bits);

reinit_completion(&p->done);
+ p->slave_aborted = false;

/* Now start DMA */
if (rx)
@@ -746,11 +781,9 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
}

/* wait for tx fifo to be emptied / rx fifo to be filled */
- if (!wait_for_completion_timeout(&p->done, HZ)) {
- dev_err(&p->pdev->dev, "DMA timeout\n");
- ret = -ETIMEDOUT;
+ ret = sh_msiof_wait_for_completion(p);
+ if (ret)
goto stop_reset;
- }

/* clear status bits */
sh_msiof_reset_str(p);
@@ -843,7 +876,8 @@ static int sh_msiof_transfer_one(struct spi_master *master,
int ret;

/* setup clocks (clock already enabled in chipselect()) */
- sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk), t->speed_hz);
+ if (!spi_controller_is_slave(p->master))
+ sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk), t->speed_hz);

while (master->dma_tx && len > 15) {
/*
@@ -998,8 +1032,12 @@ static struct sh_msiof_spi_info *sh_msiof_spi_parse_dt(struct device *dev)
if (!info)
return NULL;

+ info->mode = of_property_read_bool(np, "spi-slave") ? MSIOF_SPI_SLAVE
+ : MSIOF_SPI_MASTER;
+
/* Parse the MSIOF properties */
- of_property_read_u32(np, "num-cs", &num_cs);
+ if (info->mode == MSIOF_SPI_MASTER)
+ of_property_read_u32(np, "num-cs", &num_cs);
of_property_read_u32(np, "renesas,tx-fifo-size",
&info->tx_fifo_override);
of_property_read_u32(np, "renesas,rx-fifo-size",
@@ -1159,34 +1197,40 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
struct spi_master *master;
const struct sh_msiof_chipdata *chipdata;
const struct of_device_id *of_id;
+ struct sh_msiof_spi_info *info;
struct sh_msiof_spi_priv *p;
int i;
int ret;

- master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
- if (master == NULL)
- return -ENOMEM;
-
- p = spi_master_get_devdata(master);
-
- platform_set_drvdata(pdev, p);
- p->master = master;
-
of_id = of_match_device(sh_msiof_match, &pdev->dev);
if (of_id) {
chipdata = of_id->data;
- p->info = sh_msiof_spi_parse_dt(&pdev->dev);
+ info = sh_msiof_spi_parse_dt(&pdev->dev);
} else {
chipdata = (const void *)pdev->id_entry->driver_data;
- p->info = dev_get_platdata(&pdev->dev);
+ info = dev_get_platdata(&pdev->dev);
}

- if (!p->info) {
+ if (!info) {
dev_err(&pdev->dev, "failed to obtain device info\n");
- ret = -ENXIO;
- goto err1;
+ return -ENXIO;
}

+ if (info->mode == MSIOF_SPI_SLAVE)
+ master = spi_alloc_slave(&pdev->dev,
+ sizeof(struct sh_msiof_spi_priv));
+ else
+ master = spi_alloc_master(&pdev->dev,
+ sizeof(struct sh_msiof_spi_priv));
+ if (master == NULL)
+ return -ENOMEM;
+
+ p = spi_master_get_devdata(master);
+
+ platform_set_drvdata(pdev, p);
+ p->master = master;
+ p->info = info;
+
init_completion(&p->done);

p->clk = devm_clk_get(&pdev->dev, NULL);
@@ -1237,6 +1281,7 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
master->num_chipselect = p->info->num_chipselect;
master->setup = sh_msiof_spi_setup;
master->prepare_message = sh_msiof_prepare_message;
+ master->slave_abort = sh_msiof_slave_abort;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
master->auto_runtime_pm = true;
master->transfer_one = sh_msiof_transfer_one;
diff --git a/include/linux/spi/sh_msiof.h b/include/linux/spi/sh_msiof.h
index b087a85f5f72a351..f74b581f242f8c43 100644
--- a/include/linux/spi/sh_msiof.h
+++ b/include/linux/spi/sh_msiof.h
@@ -1,10 +1,16 @@
#ifndef __SPI_SH_MSIOF_H__
#define __SPI_SH_MSIOF_H__

+enum {
+ MSIOF_SPI_MASTER,
+ MSIOF_SPI_SLAVE,
+};
+
struct sh_msiof_spi_info {
int tx_fifo_override;
int rx_fifo_override;
u16 num_chipselect;
+ int mode;
unsigned int dma_tx_id;
unsigned int dma_rx_id;
u32 dtdl;
--
2.7.4