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From 2ade0172154e50c8a2bfd8634c6eff943cffea29 Mon Sep 17 00:00:00 2001
From: "SkyLake.Huang" <skylake.huang@mediatek.com>
Date: Thu, 23 Jun 2022 18:35:52 +0800
Subject: [PATCH 2/6] drivers: spi: Add support for dynamic calibration
Signed-off-by: SkyLake.Huang <skylake.huang@mediatek.com>
---
drivers/spi/spi.c | 137 ++++++++++++++++++++++++++++++++++++++++
include/linux/spi/spi.h | 42 ++++++++++++
2 files changed, 179 insertions(+)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1234,6 +1234,70 @@ static int spi_transfer_wait(struct spi_
return 0;
}
+int spi_do_calibration(struct spi_controller *ctlr, struct spi_device *spi,
+ int (*cal_read)(void *priv, u32 *addr, int addrlen, u8 *buf, int readlen), void *drv_priv)
+{
+ int datalen = ctlr->cal_rule->datalen;
+ int addrlen = ctlr->cal_rule->addrlen;
+ u8 *buf;
+ int ret;
+ int i;
+ struct list_head *cal_head, *listptr;
+ struct spi_cal_target *target;
+
+ /* Calculate calibration result */
+ int hit_val, total_hit, origin;
+ bool hit;
+
+ /* Make sure we can start calibration */
+ if(!ctlr->cal_target || !ctlr->cal_rule || !ctlr->append_caldata)
+ return 0;
+
+ buf = kzalloc(datalen * sizeof(u8), GFP_KERNEL);
+ if(!buf)
+ return -ENOMEM;
+
+ ret = ctlr->append_caldata(ctlr);
+ if (ret)
+ goto cal_end;
+
+ cal_head = ctlr->cal_target;
+ list_for_each(listptr, cal_head) {
+ target = list_entry(listptr, struct spi_cal_target, list);
+
+ hit = false;
+ hit_val = 0;
+ total_hit = 0;
+ origin = *target->cal_item;
+
+ for(i=target->cal_min; i<=target->cal_max; i+=target->step) {
+ *target->cal_item = i;
+ ret = (*cal_read)(drv_priv, ctlr->cal_rule->addr, addrlen, buf, datalen);
+ if(ret)
+ break;
+ dev_dbg(&spi->dev, "controller cal item value: 0x%x\n", i);
+ if(memcmp(ctlr->cal_rule->match_data, buf, datalen * sizeof(u8)) == 0) {
+ hit = true;
+ hit_val += i;
+ total_hit++;
+ dev_dbg(&spi->dev, "golden data matches data read!\n");
+ }
+ }
+ if(hit) {
+ *target->cal_item = DIV_ROUND_CLOSEST(hit_val, total_hit);
+ dev_info(&spi->dev, "calibration result: 0x%x", *target->cal_item);
+ } else {
+ *target->cal_item = origin;
+ dev_warn(&spi->dev, "calibration failed, fallback to default: 0x%x", origin);
+ }
+ }
+
+cal_end:
+ kfree(buf);
+ return ret? ret: 0;
+}
+EXPORT_SYMBOL_GPL(spi_do_calibration);
+
static void _spi_transfer_delay_ns(u32 ns)
{
if (!ns)
@@ -2021,6 +2085,75 @@ void spi_flush_queue(struct spi_controll
/*-------------------------------------------------------------------------*/
#if defined(CONFIG_OF)
+static inline void alloc_cal_data(struct list_head **cal_target,
+ struct spi_cal_rule **cal_rule, bool enable)
+{
+ if(enable) {
+ *cal_target = kmalloc(sizeof(struct list_head), GFP_KERNEL);
+ INIT_LIST_HEAD(*cal_target);
+ *cal_rule = kmalloc(sizeof(struct spi_cal_rule), GFP_KERNEL);
+ } else {
+ kfree(*cal_target);
+ kfree(*cal_rule);
+ }
+}
+
+static int of_spi_parse_cal_dt(struct spi_controller *ctlr, struct spi_device *spi,
+ struct device_node *nc)
+{
+ u32 value;
+ int rc;
+ const char *cal_mode;
+
+ rc = of_property_read_bool(nc, "spi-cal-enable");
+ if (rc)
+ alloc_cal_data(&ctlr->cal_target, &ctlr->cal_rule, true);
+ else
+ return 0;
+
+ rc = of_property_read_string(nc, "spi-cal-mode", &cal_mode);
+ if(!rc) {
+ if(strcmp("read-data", cal_mode) == 0){
+ ctlr->cal_rule->mode = SPI_CAL_READ_DATA;
+ } else if(strcmp("read-pp", cal_mode) == 0) {
+ ctlr->cal_rule->mode = SPI_CAL_READ_PP;
+ return 0;
+ } else if(strcmp("read-sfdp", cal_mode) == 0){
+ ctlr->cal_rule->mode = SPI_CAL_READ_SFDP;
+ return 0;
+ }
+ } else
+ goto err;
+
+ ctlr->cal_rule->datalen = 0;
+ rc = of_property_read_u32(nc, "spi-cal-datalen", &value);
+ if(!rc && value > 0) {
+ ctlr->cal_rule->datalen = value;
+
+ ctlr->cal_rule->match_data = kzalloc(value * sizeof(u8), GFP_KERNEL);
+ rc = of_property_read_u8_array(nc, "spi-cal-data",
+ ctlr->cal_rule->match_data, value);
+ if(rc)
+ kfree(ctlr->cal_rule->match_data);
+ }
+
+ rc = of_property_read_u32(nc, "spi-cal-addrlen", &value);
+ if(!rc && value > 0) {
+ ctlr->cal_rule->addrlen = value;
+
+ ctlr->cal_rule->addr = kzalloc(value * sizeof(u32), GFP_KERNEL);
+ rc = of_property_read_u32_array(nc, "spi-cal-addr",
+ ctlr->cal_rule->addr, value);
+ if(rc)
+ kfree(ctlr->cal_rule->addr);
+ }
+ return 0;
+
+err:
+ alloc_cal_data(&ctlr->cal_target, &ctlr->cal_rule, false);
+ return 0;
+}
+
static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
struct device_node *nc)
{
@@ -2139,6 +2272,10 @@ of_register_spi_device(struct spi_contro
if (rc)
goto err_out;
+ rc = of_spi_parse_cal_dt(ctlr, spi, nc);
+ if (rc)
+ goto err_out;
+
/* Store a pointer to the node in the device structure */
of_node_get(nc);
spi->dev.of_node = nc;
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -290,6 +290,40 @@ struct spi_driver {
struct device_driver driver;
};
+enum {
+ SPI_CAL_READ_DATA = 0,
+ SPI_CAL_READ_PP = 1, /* only for SPI-NAND */
+ SPI_CAL_READ_SFDP = 2, /* only for SPI-NOR */
+};
+
+struct nand_addr {
+ unsigned int lun;
+ unsigned int plane;
+ unsigned int eraseblock;
+ unsigned int page;
+ unsigned int dataoffs;
+};
+
+/**
+ * Read calibration rule from device dts node.
+ * Once calibration result matches the rule, we regard is as success.
+ */
+struct spi_cal_rule {
+ int datalen;
+ u8 *match_data;
+ int addrlen;
+ u32 *addr;
+ int mode;
+};
+
+struct spi_cal_target {
+ u32 *cal_item;
+ int cal_min; /* min of cal_item */
+ int cal_max; /* max of cal_item */
+ int step; /* Increase/decrease cal_item */
+ struct list_head list;
+};
+
static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
{
return drv ? container_of(drv, struct spi_driver, driver) : NULL;
@@ -665,6 +699,11 @@ struct spi_controller {
void *dummy_rx;
void *dummy_tx;
+ /* For calibration */
+ int (*append_caldata)(struct spi_controller *ctlr);
+ struct list_head *cal_target;
+ struct spi_cal_rule *cal_rule;
+
int (*fw_translate_cs)(struct spi_controller *ctlr, unsigned cs);
/*
@@ -1477,6 +1516,9 @@ spi_register_board_info(struct spi_board
{ return 0; }
#endif
+extern int spi_do_calibration(struct spi_controller *ctlr,
+ struct spi_device *spi, int (*cal_read)(void *, u32 *, int, u8 *, int), void *drv_priv);
+
/* If you're hotplugging an adapter with devices (parport, usb, etc)
* use spi_new_device() to describe each device. You can also call
* spi_unregister_device() to start making that device vanish, but
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