Commit ec17f143 authored by Adrian Ng Ho Yin's avatar Adrian Ng Ho Yin Committed by Alexandre Belloni
Browse files

i3c: dw: Add support for Device NACK Retry configuration 



The DesignWare I3C controller supports automatically retrying transactions
when a device NACKs. This is useful for slave devices that may be
temporarily busy and not ready to respond immediately.

Add new ops to configure all active DAT entry with dev_nack_retry during
runtime. Returns error when value exceeds hw specified limit.

Signed-off-by: default avatarAdrian Ng Ho Yin <adrianhoyin.ng@altera.com>
Reviewed-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/f09ee67e61d31f0a12a0bf48f01e9057ca9e2fb7.1765529948.git.adrianhoyin.ng@altera.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent b58f47eb

drivers/i3c/master/dw-i3c-master.c

+40 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Author: Vitor Soares <vitor.soares@synopsys.com>

 */



#include <linux/bitfield.h>

#include <linux/bitops.h>

#include <linux/clk.h>

#include <linux/completion.h>
@@ -204,8 +205,12 @@ 
#define EXTENDED_CAPABILITY		0xe8

#define SLAVE_CONFIG			0xec



#define DW_I3C_DEV_NACK_RETRY_CNT_MAX	0x3

#define DEV_ADDR_TABLE_DEV_NACK_RETRY_MASK   GENMASK(30, 29)

#define DEV_ADDR_TABLE_IBI_MDB		BIT(12)

#define DEV_ADDR_TABLE_SIR_REJECT	BIT(13)

#define DEV_ADDR_TABLE_DEV_NACK_RETRY_CNT(x) \

	FIELD_PREP(DEV_ADDR_TABLE_DEV_NACK_RETRY_MASK, (x))

#define DEV_ADDR_TABLE_LEGACY_I2C_DEV	BIT(31)

#define DEV_ADDR_TABLE_DYNAMIC_ADDR(x)	(((x) << 16) & GENMASK(23, 16))

#define DEV_ADDR_TABLE_STATIC_ADDR(x)	((x) & GENMASK(6, 0))
@@ -1489,6 +1494,40 @@ static irqreturn_t dw_i3c_master_irq_handler(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



static int dw_i3c_master_set_dev_nack_retry(struct i3c_master_controller *m,

					    unsigned long dev_nack_retry_cnt)

{

	struct dw_i3c_master *master = to_dw_i3c_master(m);

	u32 reg;

	int i;



	if (dev_nack_retry_cnt > DW_I3C_DEV_NACK_RETRY_CNT_MAX) {

		dev_err(&master->base.dev,

			"Value %ld exceeds maximum %d\n",

			dev_nack_retry_cnt, DW_I3C_DEV_NACK_RETRY_CNT_MAX);

		return -ERANGE;

	}



	/*

	 * Update DAT entries for all currently attached devices.

	 * We directly iterate through the master's device array.

	 */

	for (i = 0; i < master->maxdevs; i++) {

		/* Skip free/empty slots */

		if (master->free_pos & BIT(i))

			continue;



		reg = readl(master->regs +

				DEV_ADDR_TABLE_LOC(master->datstartaddr, i));

		reg &= ~DEV_ADDR_TABLE_DEV_NACK_RETRY_MASK;

		reg |= DEV_ADDR_TABLE_DEV_NACK_RETRY_CNT(dev_nack_retry_cnt);

		writel(reg, master->regs +

			DEV_ADDR_TABLE_LOC(master->datstartaddr, i));

	}



	return 0;

}



static const struct i3c_master_controller_ops dw_mipi_i3c_ops = {

	.bus_init = dw_i3c_master_bus_init,

	.bus_cleanup = dw_i3c_master_bus_cleanup,
@@ -1509,6 +1548,7 @@ static const struct i3c_master_controller_ops dw_mipi_i3c_ops = { 
	.recycle_ibi_slot = dw_i3c_master_recycle_ibi_slot,

	.enable_hotjoin = dw_i3c_master_enable_hotjoin,

	.disable_hotjoin = dw_i3c_master_disable_hotjoin,

	.set_dev_nack_retry = dw_i3c_master_set_dev_nack_retry,

};



/* default platform ops implementations */