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path: root/drivers/net/wireless/microchip/wilc1000/spi.c
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Diffstat (limited to 'drivers/net/wireless/microchip/wilc1000/spi.c')
-rw-r--r--drivers/net/wireless/microchip/wilc1000/spi.c298
1 files changed, 222 insertions, 76 deletions
diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index be732929322c..1472e9843896 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -7,12 +7,41 @@
#include <linux/clk.h>
#include <linux/spi/spi.h>
#include <linux/crc7.h>
+#include <linux/crc-itu-t.h>
#include "netdev.h"
#include "cfg80211.h"
+static bool enable_crc7; /* protect SPI commands with CRC7 */
+module_param(enable_crc7, bool, 0644);
+MODULE_PARM_DESC(enable_crc7,
+ "Enable CRC7 checksum to protect command transfers\n"
+ "\t\t\tagainst corruption during the SPI transfer.\n"
+ "\t\t\tCommand transfers are short and the CPU-cycle cost\n"
+ "\t\t\tof enabling this is small.");
+
+static bool enable_crc16; /* protect SPI data with CRC16 */
+module_param(enable_crc16, bool, 0644);
+MODULE_PARM_DESC(enable_crc16,
+ "Enable CRC16 checksum to protect data transfers\n"
+ "\t\t\tagainst corruption during the SPI transfer.\n"
+ "\t\t\tData transfers can be large and the CPU-cycle cost\n"
+ "\t\t\tof enabling this may be substantial.");
+
+/*
+ * For CMD_SINGLE_READ and CMD_INTERNAL_READ, WILC may insert one or
+ * more zero bytes between the command response and the DATA Start tag
+ * (0xf3). This behavior appears to be undocumented in "ATWILC1000
+ * USER GUIDE" (https://tinyurl.com/4hhshdts) but we have observed 1-4
+ * zero bytes when the SPI bus operates at 48MHz and none when it
+ * operates at 1MHz.
+ */
+#define WILC_SPI_RSP_HDR_EXTRA_DATA 8
+
struct wilc_spi {
- int crc_off;
+ bool probing_crc; /* true if we're probing chip's CRC config */
+ bool crc7_enabled; /* true if crc7 is currently enabled */
+ bool crc16_enabled; /* true if crc16 is currently enabled */
};
static const struct wilc_hif_func wilc_hif_spi;
@@ -36,12 +65,36 @@ static const struct wilc_hif_func wilc_hif_spi;
#define CMD_RESET 0xcf
#define SPI_ENABLE_VMM_RETRY_LIMIT 2
-#define DATA_PKT_SZ_256 256
-#define DATA_PKT_SZ_512 512
-#define DATA_PKT_SZ_1K 1024
-#define DATA_PKT_SZ_4K (4 * 1024)
-#define DATA_PKT_SZ_8K (8 * 1024)
-#define DATA_PKT_SZ DATA_PKT_SZ_8K
+
+/* SPI response fields (section 11.1.2 in ATWILC1000 User Guide): */
+#define RSP_START_FIELD GENMASK(7, 4)
+#define RSP_TYPE_FIELD GENMASK(3, 0)
+
+/* SPI response values for the response fields: */
+#define RSP_START_TAG 0xc
+#define RSP_TYPE_FIRST_PACKET 0x1
+#define RSP_TYPE_INNER_PACKET 0x2
+#define RSP_TYPE_LAST_PACKET 0x3
+#define RSP_STATE_NO_ERROR 0x00
+
+#define PROTOCOL_REG_PKT_SZ_MASK GENMASK(6, 4)
+#define PROTOCOL_REG_CRC16_MASK GENMASK(3, 3)
+#define PROTOCOL_REG_CRC7_MASK GENMASK(2, 2)
+
+/*
+ * The SPI data packet size may be any integer power of two in the
+ * range from 256 to 8192 bytes.
+ */
+#define DATA_PKT_LOG_SZ_MIN 8 /* 256 B */
+#define DATA_PKT_LOG_SZ_MAX 13 /* 8 KiB */
+
+/*
+ * Select the data packet size (log2 of number of bytes): Use the
+ * maximum data packet size. We only retransmit complete packets, so
+ * there is no benefit from using smaller data packets.
+ */
+#define DATA_PKT_LOG_SZ DATA_PKT_LOG_SZ_MAX
+#define DATA_PKT_SZ (1 << DATA_PKT_LOG_SZ)
#define USE_SPI_DMA 0
@@ -79,16 +132,15 @@ struct wilc_spi_cmd {
} __packed;
struct wilc_spi_read_rsp_data {
- u8 rsp_cmd_type;
- u8 status;
- u8 resp_header;
- u8 resp_data[4];
+ u8 header;
+ u8 data[4];
u8 crc[];
} __packed;
struct wilc_spi_rsp_data {
u8 rsp_cmd_type;
u8 status;
+ u8 data[];
} __packed;
static int wilc_bus_probe(struct spi_device *spi)
@@ -281,7 +333,8 @@ static int spi_data_write(struct wilc *wilc, u8 *b, u32 sz)
struct wilc_spi *spi_priv = wilc->bus_data;
int ix, nbytes;
int result = 0;
- u8 cmd, order, crc[2] = {0};
+ u8 cmd, order, crc[2];
+ u16 crc_calc;
/*
* Data
@@ -323,9 +376,12 @@ static int spi_data_write(struct wilc *wilc, u8 *b, u32 sz)
}
/*
- * Write Crc
+ * Write CRC
*/
- if (!spi_priv->crc_off) {
+ if (spi_priv->crc16_enabled) {
+ crc_calc = crc_itu_t(0xffff, &b[ix], nbytes);
+ crc[0] = crc_calc >> 8;
+ crc[1] = crc_calc;
if (wilc_spi_tx(wilc, crc, 2)) {
dev_err(&spi->dev, "Failed data block crc write, bus error...\n");
result = -EINVAL;
@@ -359,10 +415,11 @@ static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
struct spi_device *spi = to_spi_device(wilc->dev);
struct wilc_spi *spi_priv = wilc->bus_data;
u8 wb[32], rb[32];
- int cmd_len, resp_len;
- u8 crc[2];
+ int cmd_len, resp_len, i;
+ u16 crc_calc, crc_recv;
struct wilc_spi_cmd *c;
- struct wilc_spi_read_rsp_data *r;
+ struct wilc_spi_rsp_data *r;
+ struct wilc_spi_read_rsp_data *r_data;
memset(wb, 0x0, sizeof(wb));
memset(rb, 0x0, sizeof(rb));
@@ -384,8 +441,9 @@ static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
}
cmd_len = offsetof(struct wilc_spi_cmd, u.simple_cmd.crc);
- resp_len = sizeof(*r);
- if (!spi_priv->crc_off) {
+ resp_len = sizeof(*r) + sizeof(*r_data) + WILC_SPI_RSP_HDR_EXTRA_DATA;
+
+ if (spi_priv->crc7_enabled) {
c->u.simple_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
cmd_len += 1;
resp_len += 2;
@@ -403,11 +461,12 @@ static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
return -EINVAL;
}
- r = (struct wilc_spi_read_rsp_data *)&rb[cmd_len];
+ r = (struct wilc_spi_rsp_data *)&rb[cmd_len];
if (r->rsp_cmd_type != cmd) {
- dev_err(&spi->dev,
- "Failed cmd response, cmd (%02x), resp (%02x)\n",
- cmd, r->rsp_cmd_type);
+ if (!spi_priv->probing_crc)
+ dev_err(&spi->dev,
+ "Failed cmd, cmd (%02x), resp (%02x)\n",
+ cmd, r->rsp_cmd_type);
return -EINVAL;
}
@@ -417,17 +476,30 @@ static int wilc_spi_single_read(struct wilc *wilc, u8 cmd, u32 adr, void *b,
return -EINVAL;
}
- if (WILC_GET_RESP_HDR_START(r->resp_header) != 0xf) {
- dev_err(&spi->dev, "Error, data read response (%02x)\n",
- r->resp_header);
+ for (i = 0; i < WILC_SPI_RSP_HDR_EXTRA_DATA; ++i)
+ if (WILC_GET_RESP_HDR_START(r->data[i]) == 0xf)
+ break;
+
+ if (i >= WILC_SPI_RSP_HDR_EXTRA_DATA) {
+ dev_err(&spi->dev, "Error, data start missing\n");
return -EINVAL;
}
- if (b)
- memcpy(b, r->resp_data, 4);
+ r_data = (struct wilc_spi_read_rsp_data *)&r->data[i];
- if (!spi_priv->crc_off)
- memcpy(crc, r->crc, 2);
+ if (b)
+ memcpy(b, r_data->data, 4);
+
+ if (!clockless && spi_priv->crc16_enabled) {
+ crc_recv = (r_data->crc[0] << 8) | r_data->crc[1];
+ crc_calc = crc_itu_t(0xffff, r_data->data, 4);
+ if (crc_recv != crc_calc) {
+ dev_err(&spi->dev, "%s: bad CRC 0x%04x "
+ "(calculated 0x%04x)\n", __func__,
+ crc_recv, crc_calc);
+ return -EINVAL;
+ }
+ }
return 0;
}
@@ -454,7 +526,7 @@ static int wilc_spi_write_cmd(struct wilc *wilc, u8 cmd, u32 adr, u32 data,
c->u.internal_w_cmd.addr[1] = adr;
c->u.internal_w_cmd.data = cpu_to_be32(data);
cmd_len = offsetof(struct wilc_spi_cmd, u.internal_w_cmd.crc);
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
c->u.internal_w_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
} else if (cmd == CMD_SINGLE_WRITE) {
c->u.w_cmd.addr[0] = adr >> 16;
@@ -462,14 +534,14 @@ static int wilc_spi_write_cmd(struct wilc *wilc, u8 cmd, u32 adr, u32 data,
c->u.w_cmd.addr[2] = adr;
c->u.w_cmd.data = cpu_to_be32(data);
cmd_len = offsetof(struct wilc_spi_cmd, u.w_cmd.crc);
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
c->u.w_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
} else {
dev_err(&spi->dev, "write cmd [%x] not supported\n", cmd);
return -EINVAL;
}
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
cmd_len += 1;
resp_len = sizeof(*r);
@@ -507,6 +579,7 @@ static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
{
struct spi_device *spi = to_spi_device(wilc->dev);
struct wilc_spi *spi_priv = wilc->bus_data;
+ u16 crc_recv, crc_calc;
u8 wb[32], rb[32];
int cmd_len, resp_len;
int retry, ix = 0;
@@ -525,7 +598,7 @@ static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
c->u.dma_cmd.size[0] = sz >> 8;
c->u.dma_cmd.size[1] = sz;
cmd_len = offsetof(struct wilc_spi_cmd, u.dma_cmd.crc);
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
c->u.dma_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
} else if (cmd == CMD_DMA_EXT_WRITE || cmd == CMD_DMA_EXT_READ) {
c->u.dma_cmd_ext.addr[0] = adr >> 16;
@@ -535,14 +608,14 @@ static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
c->u.dma_cmd_ext.size[1] = sz >> 8;
c->u.dma_cmd_ext.size[2] = sz;
cmd_len = offsetof(struct wilc_spi_cmd, u.dma_cmd_ext.crc);
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
c->u.dma_cmd_ext.crc[0] = wilc_get_crc7(wb, cmd_len);
} else {
dev_err(&spi->dev, "dma read write cmd [%x] not supported\n",
cmd);
return -EINVAL;
}
- if (!spi_priv->crc_off)
+ if (spi_priv->crc7_enabled)
cmd_len += 1;
resp_len = sizeof(*r);
@@ -608,12 +681,22 @@ static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
}
/*
- * Read Crc
+ * Read CRC
*/
- if (!spi_priv->crc_off && wilc_spi_rx(wilc, crc, 2)) {
- dev_err(&spi->dev,
- "Failed block crc read, bus err\n");
- return -EINVAL;
+ if (spi_priv->crc16_enabled) {
+ if (wilc_spi_rx(wilc, crc, 2)) {
+ dev_err(&spi->dev,
+ "Failed block CRC read, bus err\n");
+ return -EINVAL;
+ }
+ crc_recv = (crc[0] << 8) | crc[1];
+ crc_calc = crc_itu_t(0xffff, &b[ix], nbytes);
+ if (crc_recv != crc_calc) {
+ dev_err(&spi->dev, "%s: bad CRC 0x%04x "
+ "(calculated 0x%04x)\n", __func__,
+ crc_recv, crc_calc);
+ return -EINVAL;
+ }
}
ix += nbytes;
@@ -680,11 +763,13 @@ static int spi_internal_write(struct wilc *wilc, u32 adr, u32 dat)
static int spi_internal_read(struct wilc *wilc, u32 adr, u32 *data)
{
struct spi_device *spi = to_spi_device(wilc->dev);
+ struct wilc_spi *spi_priv = wilc->bus_data;
int result;
result = wilc_spi_single_read(wilc, CMD_INTERNAL_READ, adr, data, 0);
if (result) {
- dev_err(&spi->dev, "Failed internal read cmd...\n");
+ if (!spi_priv->probing_crc)
+ dev_err(&spi->dev, "Failed internal read cmd...\n");
return result;
}
@@ -721,6 +806,52 @@ static int wilc_spi_write_reg(struct wilc *wilc, u32 addr, u32 data)
return 0;
}
+static int spi_data_rsp(struct wilc *wilc, u8 cmd)
+{
+ struct spi_device *spi = to_spi_device(wilc->dev);
+ int result, i;
+ u8 rsp[4];
+
+ /*
+ * The response to data packets is two bytes long. For
+ * efficiency's sake, wilc_spi_write() wisely ignores the
+ * responses for all packets but the final one. The downside
+ * of that optimization is that when the final data packet is
+ * short, we may receive (part of) the response to the
+ * second-to-last packet before the one for the final packet.
+ * To handle this, we always read 4 bytes and then search for
+ * the last byte that contains the "Response Start" code (0xc
+ * in the top 4 bits). We then know that this byte is the
+ * first response byte of the final data packet.
+ */
+ result = wilc_spi_rx(wilc, rsp, sizeof(rsp));
+ if (result) {
+ dev_err(&spi->dev, "Failed bus error...\n");
+ return result;
+ }
+
+ for (i = sizeof(rsp) - 2; i >= 0; --i)
+ if (FIELD_GET(RSP_START_FIELD, rsp[i]) == RSP_START_TAG)
+ break;
+
+ if (i < 0) {
+ dev_err(&spi->dev,
+ "Data packet response missing (%02x %02x %02x %02x)\n",
+ rsp[0], rsp[1], rsp[2], rsp[3]);
+ return -1;
+ }
+
+ /* rsp[i] is the last response start byte */
+
+ if (FIELD_GET(RSP_TYPE_FIELD, rsp[i]) != RSP_TYPE_LAST_PACKET
+ || rsp[i + 1] != RSP_STATE_NO_ERROR) {
+ dev_err(&spi->dev, "Data response error (%02x %02x)\n",
+ rsp[i], rsp[i + 1]);
+ return -1;
+ }
+ return 0;
+}
+
static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
{
struct spi_device *spi = to_spi_device(wilc->dev);
@@ -748,7 +879,10 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
return result;
}
- return 0;
+ /*
+ * Data response
+ */
+ return spi_data_rsp(wilc, CMD_DMA_EXT_WRITE);
}
/********************************************
@@ -772,7 +906,7 @@ static int wilc_spi_init(struct wilc *wilc, bool resume)
u32 reg;
u32 chipid;
static int isinit;
- int ret;
+ int ret, i;
if (isinit) {
ret = wilc_spi_read_reg(wilc, WILC_CHIPID, &chipid);
@@ -787,42 +921,54 @@ static int wilc_spi_init(struct wilc *wilc, bool resume)
*/
/*
- * TODO: We can remove the CRC trials if there is a definite
- * way to reset
+ * Infer the CRC settings that are currently in effect. This
+ * is necessary because we can't be sure that the chip has
+ * been RESET (e.g, after module unload and reload).
*/
- /* the SPI to it's initial value. */
- ret = spi_internal_read(wilc, WILC_SPI_PROTOCOL_OFFSET, &reg);
- if (ret) {
- /*
- * Read failed. Try with CRC off. This might happen when module
- * is removed but chip isn't reset
- */
- spi_priv->crc_off = 1;
- dev_err(&spi->dev,
- "Failed read with CRC on, retrying with CRC off\n");
+ spi_priv->probing_crc = true;
+ spi_priv->crc7_enabled = enable_crc7;
+ spi_priv->crc16_enabled = false; /* don't check CRC16 during probing */
+ for (i = 0; i < 2; ++i) {
ret = spi_internal_read(wilc, WILC_SPI_PROTOCOL_OFFSET, &reg);
- if (ret) {
- /*
- * Read failed with both CRC on and off,
- * something went bad
- */
- dev_err(&spi->dev, "Failed internal read protocol\n");
- return ret;
- }
+ if (ret == 0)
+ break;
+ spi_priv->crc7_enabled = !enable_crc7;
}
- if (spi_priv->crc_off == 0) {
- reg &= ~0xc; /* disable crc checking */
- reg &= ~0x70;
- reg |= (0x5 << 4);
- ret = spi_internal_write(wilc, WILC_SPI_PROTOCOL_OFFSET, reg);
- if (ret) {
- dev_err(&spi->dev,
- "[wilc spi %d]: Failed internal write reg\n",
- __LINE__);
- return ret;
- }
- spi_priv->crc_off = 1;
+ if (ret) {
+ dev_err(&spi->dev, "Failed with CRC7 on and off.\n");
+ return ret;
+ }
+
+ /* set up the desired CRC configuration: */
+ reg &= ~(PROTOCOL_REG_CRC7_MASK | PROTOCOL_REG_CRC16_MASK);
+ if (enable_crc7)
+ reg |= PROTOCOL_REG_CRC7_MASK;
+ if (enable_crc16)
+ reg |= PROTOCOL_REG_CRC16_MASK;
+
+ /* set up the data packet size: */
+ BUILD_BUG_ON(DATA_PKT_LOG_SZ < DATA_PKT_LOG_SZ_MIN
+ || DATA_PKT_LOG_SZ > DATA_PKT_LOG_SZ_MAX);
+ reg &= ~PROTOCOL_REG_PKT_SZ_MASK;
+ reg |= FIELD_PREP(PROTOCOL_REG_PKT_SZ_MASK,
+ DATA_PKT_LOG_SZ - DATA_PKT_LOG_SZ_MIN);
+
+ /* establish the new setup: */
+ ret = spi_internal_write(wilc, WILC_SPI_PROTOCOL_OFFSET, reg);
+ if (ret) {
+ dev_err(&spi->dev,
+ "[wilc spi %d]: Failed internal write reg\n",
+ __LINE__);
+ return ret;
}
+ /* update our state to match new protocol settings: */
+ spi_priv->crc7_enabled = enable_crc7;
+ spi_priv->crc16_enabled = enable_crc16;
+
+ /* re-read to make sure new settings are in effect: */
+ spi_internal_read(wilc, WILC_SPI_PROTOCOL_OFFSET, &reg);
+
+ spi_priv->probing_crc = false;
/*
* make sure can read back chip id correctly
generated by cgit v1.2.3 (git 2.39.0) at 2025-10-31 17:13:09 +0300