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fsi/gpio: Use relative-addressing commands 

FSI CFAMs support shorter commands that use a relative (or same) address
as the last. This change introduces a last_addr to the master state, and
uses it for subsequent reads/writes, and performs relative addressing
when a subsequent read/write is in range.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
This commit is contained in:
Jeremy Kerr 2018-05-10 17:22:05 +08:00 committed by Benjamin Herrenschmidt
parent 8193fb4451
commit 0e82e5c1fa
1 changed files with 93 additions and 13 deletions
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106
drivers/fsi/fsi-master-gpio.c
View File

@ -28,6 +28,8 @@
#define FSI_GPIO_CMD_DPOLL 0x2
#define FSI_GPIO_CMD_TERM 0x3f
#define FSI_GPIO_CMD_ABS_AR 0x4
#define FSI_GPIO_CMD_REL_AR 0x5
#define FSI_GPIO_CMD_SAME_AR 0x3 /* but only a 2-bit opcode... */
#define FSI_GPIO_DPOLL_CLOCKS 50 /* < 21 will cause slave to hang */
@ -52,6 +54,8 @@
#define FSI_GPIO_MSG_RESPID_SIZE 2
#define FSI_GPIO_PRIME_SLAVE_CLOCKS 20
#define LAST_ADDR_INVALID 0x1
struct fsi_master_gpio {
struct fsi_master master;
struct device *dev;
@ -64,6 +68,7 @@ struct fsi_master_gpio {
struct gpio_desc *gpio_mux; /* Mux control */
bool external_mode;
bool no_delays;
uint32_t last_addr;
};
#define CREATE_TRACE_POINTS
@ -205,22 +210,89 @@ static void msg_push_crc(struct fsi_gpio_msg *msg)
msg_push_bits(msg, crc, 4);
}
/*
* Encode an Absolute Address command
*/
static void build_abs_ar_command(struct fsi_gpio_msg *cmd,
uint8_t id, uint32_t addr, size_t size, const void *data)
static bool check_same_address(struct fsi_master_gpio *master, int id,
uint32_t addr)
{
/* this will also handle LAST_ADDR_INVALID */
return master->last_addr == (((id & 0x3) << 21) | (addr & ~0x3));
}
static bool check_relative_address(struct fsi_master_gpio *master, int id,
uint32_t addr, uint32_t *rel_addrp)
{
uint32_t last_addr = master->last_addr;
int32_t rel_addr;
if (last_addr == LAST_ADDR_INVALID)
return false;
/* We may be in 23-bit addressing mode, which uses the id as the
* top two address bits. So, if we're referencing a different ID,
* use absolute addresses.
*/
if (((last_addr >> 21) & 0x3) != id)
return false;
/* remove the top two bits from any 23-bit addressing */
last_addr &= (1 << 21) - 1;
/* We know that the addresses are limited to 21 bits, so this won't
* overflow the signed rel_addr */
rel_addr = addr - last_addr;
if (rel_addr > 255 || rel_addr < -256)
return false;
*rel_addrp = (uint32_t)rel_addr;
return true;
}
static void last_address_update(struct fsi_master_gpio *master,
int id, bool valid, uint32_t addr)
{
if (!valid)
master->last_addr = LAST_ADDR_INVALID;
else
master->last_addr = ((id & 0x3) << 21) | (addr & ~0x3);
}
/*
* Encode an Absolute/Relative/Same Address command
*/
static void build_ar_command(struct fsi_master_gpio *master,
struct fsi_gpio_msg *cmd, uint8_t id,
uint32_t addr, size_t size, const void *data)
{
int i, addr_bits, opcode_bits;
bool write = !!data;
uint8_t ds;
int i;
uint8_t ds, opcode;
uint32_t rel_addr;
cmd->bits = 0;
cmd->msg = 0;
msg_push_bits(cmd, id, 2);
msg_push_bits(cmd, FSI_GPIO_CMD_ABS_AR, 3);
msg_push_bits(cmd, write ? 0 : 1, 1);
/* we have 21 bits of address max */
addr &= ((1 << 21) - 1);
/* cmd opcodes are variable length - SAME_AR is only two bits */
opcode_bits = 3;
if (check_same_address(master, id, addr)) {
/* we still address the byte offset within the word */
addr_bits = 2;
opcode_bits = 2;
opcode = FSI_GPIO_CMD_SAME_AR;
} else if (check_relative_address(master, id, addr, &rel_addr)) {
/* 8 bits plus sign */
addr_bits = 9;
addr = rel_addr;
opcode = FSI_GPIO_CMD_REL_AR;
} else {
addr_bits = 21;
opcode = FSI_GPIO_CMD_ABS_AR;
}
/*
* The read/write size is encoded in the lower bits of the address
@ -237,7 +309,10 @@ static void build_abs_ar_command(struct fsi_gpio_msg *cmd,
if (size == 4)
addr |= 1;
msg_push_bits(cmd, addr & ((1 << 21) - 1), 21);
msg_push_bits(cmd, id, 2);
msg_push_bits(cmd, opcode, opcode_bits);
msg_push_bits(cmd, write ? 0 : 1, 1);
msg_push_bits(cmd, addr, addr_bits);
msg_push_bits(cmd, ds, 1);
for (i = 0; write && i < size; i++)
msg_push_bits(cmd, ((uint8_t *)data)[i], 8);
@ -481,8 +556,9 @@ static int fsi_master_gpio_read(struct fsi_master *_master, int link,
return -ENODEV;
mutex_lock(&master->cmd_lock);
build_abs_ar_command(&cmd, id, addr, size, NULL);
build_ar_command(master, &cmd, id, addr, size, NULL);
rc = fsi_master_gpio_xfer(master, id, &cmd, size, val);
last_address_update(master, id, rc == 0, addr);
mutex_unlock(&master->cmd_lock);
return rc;
@ -499,8 +575,9 @@ static int fsi_master_gpio_write(struct fsi_master *_master, int link,
return -ENODEV;
mutex_lock(&master->cmd_lock);
build_abs_ar_command(&cmd, id, addr, size, val);
build_ar_command(master, &cmd, id, addr, size, val);
rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
last_address_update(master, id, rc == 0, addr);
mutex_unlock(&master->cmd_lock);
return rc;
@ -519,6 +596,7 @@ static int fsi_master_gpio_term(struct fsi_master *_master,
mutex_lock(&master->cmd_lock);
build_term_command(&cmd, id);
rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
last_address_update(master, id, false, 0);
mutex_unlock(&master->cmd_lock);
return rc;
@ -552,6 +630,7 @@ static int fsi_master_gpio_break(struct fsi_master *_master, int link)
clock_toggle(master, FSI_POST_BREAK_CLOCKS);
spin_unlock_irqrestore(&master->bit_lock, flags);
last_address_update(master, 0, false, 0);
mutex_unlock(&master->cmd_lock);
/* Wait for logic reset to take effect */
@ -662,6 +741,7 @@ static int fsi_master_gpio_probe(struct platform_device *pdev)
master->dev = &pdev->dev;
master->master.dev.parent = master->dev;
master->master.dev.of_node = of_node_get(dev_of_node(master->dev));
master->last_addr = LAST_ADDR_INVALID;
gpio = devm_gpiod_get(&pdev->dev, "clock", 0);
if (IS_ERR(gpio)) {