[PATCH v3 1/2] drm: renesas: rz-du: Implement MIPI DSI host transfers
Hugo Villeneuve
hugo at hugovil.com
Thu May 22 14:39:10 UTC 2025
From: Hugo Villeneuve <hvilleneuve at dimonoff.com>
Add support for sending MIPI DSI command packets from the host to a
peripheral. This is required for panels that need configuration before
they accept video data.
Based on Renesas Linux kernel v5.10 repos [1].
Link: https://github.com/renesas-rz/rz_linux-cip.git
Cc: Biju Das <biju.das.jz at bp.renesas.com>
Cc: Chris Brandt <chris.brandt at renesas.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve at dimonoff.com>
---
.../gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 176 ++++++++++++++++++
.../drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h | 50 +++++
2 files changed, 226 insertions(+)
diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
index dc6ab012cdb69..a048d473db00b 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -4,8 +4,11 @@
*
* Copyright (C) 2022 Renesas Electronics Corporation
*/
+
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
@@ -23,9 +26,12 @@
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drm_probe_helper.h>
+#include <video/mipi_display.h>
#include "rzg2l_mipi_dsi_regs.h"
+#define RZG2L_DCS_BUF_SIZE 128 /* Maximum DCS buffer size in external memory. */
+
struct rzg2l_mipi_dsi {
struct device *dev;
void __iomem *mmio;
@@ -44,6 +50,10 @@ struct rzg2l_mipi_dsi {
unsigned int num_data_lanes;
unsigned int lanes;
unsigned long mode_flags;
+
+ /* DCS buffer pointers when using external memory. */
+ dma_addr_t dcs_buf_phys;
+ u8 *dcs_buf_virt;
};
static inline struct rzg2l_mipi_dsi *
@@ -651,9 +661,168 @@ static int rzg2l_mipi_dsi_host_detach(struct mipi_dsi_host *host,
return 0;
}
+static ssize_t rzg2l_mipi_dsi_read_response(struct rzg2l_mipi_dsi *dsi,
+ const struct mipi_dsi_msg *msg)
+{
+ u8 *msg_rx = msg->rx_buf;
+ u8 datatype;
+ u32 result;
+ u16 size;
+
+ result = rzg2l_mipi_dsi_link_read(dsi, RXRSS0R);
+ if (result & RXRSS0R_RXPKTDFAIL) {
+ dev_err(dsi->dev, "packet rx data did not save correctly\n");
+ return -EPROTO;
+ }
+
+ if (result & RXRSS0R_RXFAIL) {
+ dev_err(dsi->dev, "packet rx failure\n");
+ return -EPROTO;
+ }
+
+ if (!(result & RXRSS0R_RXSUC))
+ return -EPROTO;
+
+ datatype = FIELD_GET(RXRSS0R_DT, result);
+
+ switch (datatype) {
+ case 0:
+ dev_dbg(dsi->dev, "ACK\n");
+ return 0;
+ case MIPI_DSI_RX_END_OF_TRANSMISSION:
+ dev_dbg(dsi->dev, "EoTp\n");
+ return 0;
+ case MIPI_DSI_RX_ACKNOWLEDGE_AND_ERROR_REPORT:
+ dev_dbg(dsi->dev, "Acknowledge and error report: $%02x%02x\n",
+ (u8)FIELD_GET(RXRSS0R_DATA1, result),
+ (u8)FIELD_GET(RXRSS0R_DATA0, result));
+ return 0;
+ case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_1BYTE:
+ case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_1BYTE:
+ msg_rx[0] = FIELD_GET(RXRSS0R_DATA0, result);
+ return 1;
+ case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_2BYTE:
+ case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_2BYTE:
+ msg_rx[0] = FIELD_GET(RXRSS0R_DATA0, result);
+ msg_rx[1] = FIELD_GET(RXRSS0R_DATA1, result);
+ return 2;
+ case MIPI_DSI_RX_GENERIC_LONG_READ_RESPONSE:
+ case MIPI_DSI_RX_DCS_LONG_READ_RESPONSE:
+ size = FIELD_GET(RXRSS0R_WC, result);
+
+ if (size > msg->rx_len) {
+ dev_err(dsi->dev, "rx buffer too small");
+ return -ENOSPC;
+ }
+
+ memcpy(msg_rx, dsi->dcs_buf_virt, size);
+ return size;
+ default:
+ dev_err(dsi->dev, "unhandled response type: %02x\n", datatype);
+ return -EPROTO;
+ }
+}
+
+static ssize_t rzg2l_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
+ const struct mipi_dsi_msg *msg)
+{
+ struct rzg2l_mipi_dsi *dsi = host_to_rzg2l_mipi_dsi(host);
+ struct mipi_dsi_packet packet;
+ bool need_bta;
+ u32 value;
+ int ret;
+
+ ret = mipi_dsi_create_packet(&packet, msg);
+ if (ret < 0)
+ return ret;
+
+ /* Terminate operation after this descriptor is finished */
+ value = SQCH0DSC0AR_NXACT_TERM;
+
+ if (msg->flags & MIPI_DSI_MSG_REQ_ACK) {
+ need_bta = true; /* Message with explicitly requested ACK */
+ value |= FIELD_PREP(SQCH0DSC0AR_BTA, SQCH0DSC0AR_BTA_NON_READ);
+ } else if (msg->rx_buf && msg->rx_len > 0) {
+ need_bta = true; /* Read request */
+ value |= FIELD_PREP(SQCH0DSC0AR_BTA, SQCH0DSC0AR_BTA_READ);
+ } else {
+ need_bta = false;
+ value |= FIELD_PREP(SQCH0DSC0AR_BTA, SQCH0DSC0AR_BTA_NONE);
+ }
+
+ /* Set transmission speed */
+ if (msg->flags & MIPI_DSI_MSG_USE_LPM)
+ value |= SQCH0DSC0AR_SPD_LOW;
+ else
+ value |= SQCH0DSC0AR_SPD_HIGH;
+
+ /* Write TX packet header */
+ value |= FIELD_PREP(SQCH0DSC0AR_DT, packet.header[0]) |
+ FIELD_PREP(SQCH0DSC0AR_DATA0, packet.header[1]) |
+ FIELD_PREP(SQCH0DSC0AR_DATA1, packet.header[2]);
+
+ if (mipi_dsi_packet_format_is_long(msg->type)) {
+ value |= SQCH0DSC0AR_FMT_LONG;
+
+ if (packet.payload_length > RZG2L_DCS_BUF_SIZE) {
+ dev_err(dsi->dev, "Packet Tx payload size (%d) too large",
+ (unsigned int)packet.payload_length);
+ return -ENOSPC;
+ }
+
+ /* Copy TX packet payload data to memory space */
+ memcpy(dsi->dcs_buf_virt, packet.payload, packet.payload_length);
+ } else {
+ value |= SQCH0DSC0AR_FMT_SHORT;
+ }
+
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0DSC0AR, value);
+
+ /*
+ * Write: specify payload data source location, only used for
+ * long packet.
+ * Read: specify payload data storage location of response
+ * packet. Note: a read packet is always a short packet.
+ * If the response packet is a short packet or a long packet
+ * with WC = 0 (no payload), DTSEL is meaningless.
+ */
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0DSC0BR, SQCH0DSC0BR_DTSEL_MEM_SPACE);
+
+ /*
+ * Set SQCHxSR.AACTFIN bit when descriptor actions are finished.
+ * Read: set Rx result save slot number to 0 (ACTCODE).
+ */
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0DSC0CR, SQCH0DSC0CR_FINACT);
+
+ /* Set rx/tx payload data address, only relevant for long packet. */
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0DSC0DR, (u32)dsi->dcs_buf_phys);
+
+ /* Start sequence 0 operation */
+ value = rzg2l_mipi_dsi_link_read(dsi, SQCH0SET0R);
+ value |= SQCH0SET0R_START;
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0SET0R, value);
+
+ /* Wait for operation to finish */
+ ret = read_poll_timeout(rzg2l_mipi_dsi_link_read,
+ value, value & SQCH0SR_ADESFIN,
+ 2000, 20000, false, dsi, SQCH0SR);
+ if (ret == 0) {
+ /* Success: clear status bit */
+ rzg2l_mipi_dsi_link_write(dsi, SQCH0SCR, SQCH0SCR_ADESFIN);
+
+ if (need_bta)
+ ret = rzg2l_mipi_dsi_read_response(dsi, msg);
+ else
+ ret = packet.payload_length;
+ }
+
+ return ret;
+}
+
static const struct mipi_dsi_host_ops rzg2l_mipi_dsi_host_ops = {
.attach = rzg2l_mipi_dsi_host_attach,
.detach = rzg2l_mipi_dsi_host_detach,
+ .transfer = rzg2l_mipi_dsi_host_transfer,
};
/* -----------------------------------------------------------------------------
@@ -771,6 +940,11 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
if (ret < 0)
goto err_pm_disable;
+ dsi->dcs_buf_virt = dma_alloc_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE,
+ &dsi->dcs_buf_phys, GFP_KERNEL);
+ if (!dsi->dcs_buf_virt)
+ return -ENOMEM;
+
return 0;
err_phy:
@@ -785,6 +959,8 @@ static void rzg2l_mipi_dsi_remove(struct platform_device *pdev)
{
struct rzg2l_mipi_dsi *dsi = platform_get_drvdata(pdev);
+ dma_free_coherent(dsi->host.dev, RZG2L_DCS_BUF_SIZE, dsi->dcs_buf_virt,
+ dsi->dcs_buf_phys);
mipi_dsi_host_unregister(&dsi->host);
pm_runtime_disable(&pdev->dev);
}
diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
index 1dbc16ec64a4b..0e432b04188d0 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi_regs.h
@@ -81,6 +81,16 @@
#define RSTSR_SWRSTLP (1 << 1)
#define RSTSR_SWRSTHS (1 << 0)
+/* Rx Result Save Slot 0 Register */
+#define RXRSS0R 0x240
+#define RXRSS0R_RXPKTDFAIL BIT(28)
+#define RXRSS0R_RXFAIL BIT(27)
+#define RXRSS0R_RXSUC BIT(25)
+#define RXRSS0R_DT GENMASK(21, 16)
+#define RXRSS0R_DATA1 GENMASK(15, 8)
+#define RXRSS0R_DATA0 GENMASK(7, 0)
+#define RXRSS0R_WC GENMASK(15, 0) /* Word count for long packet. */
+
/* Clock Lane Stop Time Set Register */
#define CLSTPTSETR 0x314
#define CLSTPTSETR_CLKKPT(x) ((x) << 24)
@@ -148,4 +158,44 @@
#define VICH1HPSETR_HFP(x) (((x) & 0x1fff) << 16)
#define VICH1HPSETR_HBP(x) (((x) & 0x1fff) << 0)
+/* Sequence Channel 0 Set 0 Register */
+#define SQCH0SET0R 0x5c0
+#define SQCH0SET0R_START BIT(0)
+
+/* Sequence Channel 0 Status Register */
+#define SQCH0SR 0x5d0
+#define SQCH0SR_ADESFIN BIT(8)
+
+/* Sequence Channel 0 Status Clear Register */
+#define SQCH0SCR 0x5d4
+#define SQCH0SCR_ADESFIN BIT(8)
+
+/* Sequence Channel 0 Descriptor 0-A Register */
+#define SQCH0DSC0AR 0x780
+#define SQCH0DSC0AR_NXACT_TERM 0 /* Bit 28 */
+#define SQCH0DSC0AR_BTA GENMASK(27, 26)
+#define SQCH0DSC0AR_BTA_NONE 0
+#define SQCH0DSC0AR_BTA_NON_READ 1
+#define SQCH0DSC0AR_BTA_READ 2
+#define SQCH0DSC0AR_BTA_ONLY 3
+#define SQCH0DSC0AR_SPD_HIGH 0
+#define SQCH0DSC0AR_SPD_LOW BIT(25)
+#define SQCH0DSC0AR_FMT_SHORT 0
+#define SQCH0DSC0AR_FMT_LONG BIT(24)
+#define SQCH0DSC0AR_DT GENMASK(21, 16)
+#define SQCH0DSC0AR_DATA1 GENMASK(15, 8)
+#define SQCH0DSC0AR_DATA0 GENMASK(7, 0)
+
+/* Sequence Channel 0 Descriptor 0-B Register */
+#define SQCH0DSC0BR 0x784
+#define SQCH0DSC0BR_DTSEL_MEM_SPACE BIT(24) /* Use external memory */
+
+/* Sequence Channel 0 Descriptor 0-C Register */
+#define SQCH0DSC0CR 0x788
+#define SQCH0DSC0CR_FINACT BIT(0)
+#define SQCH0DSC0CR_AUXOP BIT(22)
+
+/* Sequence Channel 0 Descriptor 0-D Register */
+#define SQCH0DSC0DR 0x78c
+
#endif /* __RZG2L_MIPI_DSI_REGS_H__ */
--
2.39.5
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