libqos/ahci: add ahci command functions

This patch adds the AHCICommand structure, and a set of functions to
operate on the structure.

ahci_command_create - Initialize and create a new AHCICommand in memory
ahci_command_free - Destroy this object.
ahci_command_set_buffer - Set where the guest memory DMA buffer is.
ahci_command_commit - Write this command to the AHCI HBA.
ahci_command_issue - Issue the committed command synchronously.
ahci_command_issue_async - Issue the committed command asynchronously.
ahci_command_wait - Wait for an asynchronous command to finish.
ahci_command_slot - Get the number of the command slot we committed to.

Helpers:
size_to_prdtl       - Calculate the required minimum PRDTL size from
                      a buffer size.
ahci_command_find   - Given an ATA command mnemonic, look it up in the
                      properties table to obtain info about the command.
command_header_init - Initialize the command header with sane values.
command_table_init  - Initialize the command table with sane values.

[Peter Maydell <peter.maydell@linaro.org> reported the following clang
warning:

  tests/libqos/ahci.c:598:3: warning: redefinition
  of typedef 'AHCICommand' is a C11 feature
      [-Wtypedef-redefinition]
  } AHCICommand;

I have replaced typedef struct ... AHCICommand; with struct ... ;
--Stefan]

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1423158090-25580-13-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 237 insertions, 56 deletions

diff --git a/tests/ahci-test.c b/tests/ahci-test.c
index 658956d..0834020 100644
--- a/tests/ahci-test.c
+++ b/tests/ahci-test.c
@@ -657,30 +657,28 @@ static void ahci_test_port_spec(AHCIQState *ahci, uint8_t port)
  */
 static void ahci_test_identify(AHCIQState *ahci)
 {
-    RegH2DFIS fis;
-    AHCICommandHeader cmd;
-    PRD prd;
     uint32_t data_ptr;
     uint16_t buff[256];
     unsigned i;
     int rc;
+    AHCICommand *cmd;
     uint8_t cx;
-    uint64_t table;
 
     g_assert(ahci != NULL);
 
     /* We need to:
-     * (1) Create a Command Table Buffer and update the Command List Slot #0
-     *     to point to this buffer.
-     * (2) Construct an FIS host-to-device command structure, and write it to
+     * (1) Create a data buffer for the IDENTIFY response to be sent to,
+     * (2) Create a Command Table Buffer
+     * (3) Construct an FIS host-to-device command structure, and write it to
      *     the top of the command table buffer.
-     * (3) Create a data buffer for the IDENTIFY response to be sent to
      * (4) Create a Physical Region Descriptor that points to the data buffer,
      *     and write it to the bottom (offset 0x80) of the command table.
-     * (5) Now, PxCLB points to the command list, command 0 points to
+     * (5) Obtain a Command List slot, and update this header to point to
+     *     the Command Table we built above.
+     * (6) Now, PxCLB points to the command list, command 0 points to
      *     our table, and our table contains an FIS instruction and a
      *     PRD that points to our rx buffer.
-     * (6) We inform the HBA via PxCI that there is a command ready in slot #0.
+     * (7) We inform the HBA via PxCI that there is a command ready in slot #0.
      */
 
     /* Pick the first implemented and running port */
@@ -690,61 +688,24 @@ static void ahci_test_identify(AHCIQState *ahci)
     /* Clear out the FIS Receive area and any pending interrupts. */
     ahci_port_clear(ahci, i);
 
-    /* Create a Command Table buffer. 0x80 is the smallest with a PRDTL of 0. */
-    /* We need at least one PRD, so round up to the nearest 0x80 multiple.    */
-    table = ahci_alloc(ahci, CMD_TBL_SIZ(1));
-    g_assert(table);
-    ASSERT_BIT_CLEAR(table, 0x7F);
-
-    /* Create a data buffer ... where we will dump the IDENTIFY data to. */
+    /* Create a data buffer where we will dump the IDENTIFY data to. */
     data_ptr = ahci_alloc(ahci, 512);
     g_assert(data_ptr);
 
-    /* pick a command slot (should be 0!) */
-    cx = ahci_pick_cmd(ahci, i);
-
-    /* Construct our Command Header (set_command_header handles endianness.) */
-    memset(&cmd, 0x00, sizeof(cmd));
-    cmd.flags = 5;             /* reg_h2d_fis is 5 double-words long */
-    cmd.flags |= CMDH_CLR_BSY; /* clear PxTFD.STS.BSY when done */
-    cmd.prdtl = 1;             /* One PRD table entry. */
-    cmd.prdbc = 0;
-    cmd.ctba = table;
-
-    /* Construct our PRD, noting that DBC is 0-indexed. */
-    prd.dba = cpu_to_le64(data_ptr);
-    prd.res = 0;
-    /* 511+1 bytes, request DPS interrupt */
-    prd.dbc = cpu_to_le32(511 | 0x80000000);
-
-    /* Construct our Command FIS, Based on http://wiki.osdev.org/AHCI */
-    memset(&fis, 0x00, sizeof(fis));
-    fis.fis_type = REG_H2D_FIS;  /* Register Host-to-Device FIS */
-    fis.command = CMD_IDENTIFY;
-    fis.device = 0;
-    fis.flags = REG_H2D_FIS_CMD; /* Indicate this is a command FIS */
-
-    /* We've committed nothing yet, no interrupts should be posted yet. */
-    g_assert_cmphex(ahci_px_rreg(ahci, i, AHCI_PX_IS), ==, 0);
-
-    /* Commit the Command FIS to the Command Table */
-    ahci_write_fis(ahci, &fis, table);
-
-    /* Commit the PRD entry to the Command Table */
-    memwrite(table + 0x80, &prd, sizeof(prd));
-
-    /* Commit Command #cx, pointing to the Table, to the Command List Buffer. */
-    ahci_set_command_header(ahci, i, cx, &cmd);
+    /* Construct the Command Table (FIS and PRDT) and Command Header */
+    cmd = ahci_command_create(CMD_IDENTIFY);
+    ahci_command_set_buffer(cmd, data_ptr);
+    /* Write the command header and PRDT to guest memory */
+    ahci_command_commit(ahci, cmd, i);
 
     /* Everything is in place, but we haven't given the go-ahead yet,
      * so we should find that there are no pending interrupts yet. */
     g_assert_cmphex(ahci_px_rreg(ahci, i, AHCI_PX_IS), ==, 0);
 
     /* Issue Command #cx via PxCI */
-    ahci_px_wreg(ahci, i, AHCI_PX_CI, (1 << cx));
-    while (BITSET(ahci_px_rreg(ahci, i, AHCI_PX_TFD), AHCI_PX_TFD_STS_BSY)) {
-        usleep(50);
-    }
+    ahci_command_issue(ahci, cmd);
+    cx = ahci_command_slot(cmd);
+
     /* Check registers for post-command consistency */
     ahci_port_check_error(ahci, i);
     /* BUG: we expect AHCI_PX_IS_DPS to be set. */
diff --git a/tests/libqos/ahci.c b/tests/libqos/ahci.c
index 148aa1b..21f86c0 100644
--- a/tests/libqos/ahci.c
+++ b/tests/libqos/ahci.c
@@ -539,3 +539,205 @@ unsigned ahci_pick_cmd(AHCIQState *ahci, uint8_t port)
     g_test_message("All command slots were busy.");
     g_assert_not_reached();
 }
+
+inline unsigned size_to_prdtl(unsigned bytes, unsigned bytes_per_prd)
+{
+    /* Each PRD can describe up to 4MiB */
+    g_assert_cmphex(bytes_per_prd, <=, 4096 * 1024);
+    g_assert_cmphex(bytes_per_prd & 0x01, ==, 0x00);
+    return (bytes + bytes_per_prd - 1) / bytes_per_prd;
+}
+
+struct AHCICommand {
+    /* Test Management Data */
+    uint8_t name;
+    uint8_t port;
+    uint8_t slot;
+    uint32_t interrupts;
+    uint64_t xbytes;
+    uint32_t prd_size;
+    uint64_t buffer;
+    AHCICommandProp *props;
+    /* Data to be transferred to the guest */
+    AHCICommandHeader header;
+    RegH2DFIS fis;
+    void *atapi_cmd;
+};
+
+static AHCICommandProp *ahci_command_find(uint8_t command_name)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(ahci_command_properties); i++) {
+        if (ahci_command_properties[i].cmd == command_name) {
+            return &ahci_command_properties[i];
+        }
+    }
+
+    return NULL;
+}
+
+/**
+ * Initializes a basic command header in memory.
+ * We assume that this is for an ATA command using RegH2DFIS.
+ */
+static void command_header_init(AHCICommand *cmd)
+{
+    AHCICommandHeader *hdr = &cmd->header;
+    AHCICommandProp *props = cmd->props;
+
+    hdr->flags = 5;             /* RegH2DFIS is 5 DW long. Must be < 32 */
+    hdr->flags |= CMDH_CLR_BSY; /* Clear the BSY bit when done */
+    if (props->write) {
+        hdr->flags |= CMDH_WRITE;
+    }
+    if (props->atapi) {
+        hdr->flags |= CMDH_ATAPI;
+    }
+    /* Other flags: PREFETCH, RESET, and BIST */
+    hdr->prdtl = size_to_prdtl(cmd->xbytes, cmd->prd_size);
+    hdr->prdbc = 0;
+    hdr->ctba = 0;
+}
+
+static void command_table_init(AHCICommand *cmd)
+{
+    RegH2DFIS *fis = &(cmd->fis);
+
+    fis->fis_type = REG_H2D_FIS;
+    fis->flags = REG_H2D_FIS_CMD; /* "Command" bit */
+    fis->command = cmd->name;
+    cmd->fis.feature_low = 0x00;
+    cmd->fis.feature_high = 0x00;
+    if (cmd->props->lba28 || cmd->props->lba48) {
+        cmd->fis.device = ATA_DEVICE_LBA;
+    }
+    cmd->fis.count = (cmd->xbytes / AHCI_SECTOR_SIZE);
+    cmd->fis.icc = 0x00;
+    cmd->fis.control = 0x00;
+    memset(cmd->fis.aux, 0x00, ARRAY_SIZE(cmd->fis.aux));
+}
+
+AHCICommand *ahci_command_create(uint8_t command_name)
+{
+    AHCICommandProp *props = ahci_command_find(command_name);
+    AHCICommand *cmd;
+
+    g_assert(props);
+    cmd = g_malloc0(sizeof(AHCICommand));
+    g_assert(!(props->dma && props->pio));
+    g_assert(!(props->lba28 && props->lba48));
+    g_assert(!(props->read && props->write));
+    g_assert(!props->size || props->data);
+
+    /* Defaults and book-keeping */
+    cmd->props = props;
+    cmd->name = command_name;
+    cmd->xbytes = props->size;
+    cmd->prd_size = 4096;
+    cmd->buffer = 0xabad1dea;
+
+    cmd->interrupts = AHCI_PX_IS_DHRS;
+    /* BUG: We expect the DPS interrupt for data commands */
+    /* cmd->interrupts |= props->data ? AHCI_PX_IS_DPS : 0; */
+    /* BUG: We expect the DMA Setup interrupt for DMA commands */
+    /* cmd->interrupts |= props->dma ? AHCI_PX_IS_DSS : 0; */
+    cmd->interrupts |= props->pio ? AHCI_PX_IS_PSS : 0;
+
+    command_header_init(cmd);
+    command_table_init(cmd);
+
+    return cmd;
+}
+
+void ahci_command_free(AHCICommand *cmd)
+{
+    g_free(cmd);
+}
+
+void ahci_command_set_buffer(AHCICommand *cmd, uint64_t buffer)
+{
+    cmd->buffer = buffer;
+}
+
+void ahci_command_commit(AHCIQState *ahci, AHCICommand *cmd, uint8_t port)
+{
+    uint16_t i, prdtl;
+    uint64_t table_size, table_ptr, remaining;
+    PRD prd;
+
+    /* This command is now tied to this port/command slot */
+    cmd->port = port;
+    cmd->slot = ahci_pick_cmd(ahci, port);
+
+    /* Create a buffer for the command table */
+    prdtl = size_to_prdtl(cmd->xbytes, cmd->prd_size);
+    table_size = CMD_TBL_SIZ(prdtl);
+    table_ptr = ahci_alloc(ahci, table_size);
+    g_assert(table_ptr);
+    /* AHCI 1.3: Must be aligned to 0x80 */
+    g_assert((table_ptr & 0x7F) == 0x00);
+    cmd->header.ctba = table_ptr;
+
+    /* Commit the command header and command FIS */
+    ahci_set_command_header(ahci, port, cmd->slot, &(cmd->header));
+    ahci_write_fis(ahci, &(cmd->fis), table_ptr);
+
+    /* Construct and write the PRDs to the command table */
+    g_assert_cmphex(prdtl, ==, cmd->header.prdtl);
+    remaining = cmd->xbytes;
+    for (i = 0; i < prdtl; ++i) {
+        prd.dba = cpu_to_le64(cmd->buffer + (cmd->prd_size * i));
+        prd.res = 0;
+        if (remaining > cmd->prd_size) {
+            /* Note that byte count is 0-based. */
+            prd.dbc = cpu_to_le32(cmd->prd_size - 1);
+            remaining -= cmd->prd_size;
+        } else {
+            /* Again, dbc is 0-based. */
+            prd.dbc = cpu_to_le32(remaining - 1);
+            remaining = 0;
+        }
+        prd.dbc |= cpu_to_le32(0x80000000); /* Request DPS Interrupt */
+
+        /* Commit the PRD entry to the Command Table */
+        memwrite(table_ptr + 0x80 + (i * sizeof(PRD)),
+                 &prd, sizeof(PRD));
+    }
+
+    /* Bookmark the PRDTL and CTBA values */
+    ahci->port[port].ctba[cmd->slot] = table_ptr;
+    ahci->port[port].prdtl[cmd->slot] = prdtl;
+}
+
+void ahci_command_issue_async(AHCIQState *ahci, AHCICommand *cmd)
+{
+    if (cmd->props->ncq) {
+        ahci_px_wreg(ahci, cmd->port, AHCI_PX_SACT, (1 << cmd->slot));
+    }
+
+    ahci_px_wreg(ahci, cmd->port, AHCI_PX_CI, (1 << cmd->slot));
+}
+
+void ahci_command_wait(AHCIQState *ahci, AHCICommand *cmd)
+{
+    /* We can't rely on STS_BSY until the command has started processing.
+     * Therefore, we also use the Command Issue bit as indication of
+     * a command in-flight. */
+    while (BITSET(ahci_px_rreg(ahci, cmd->port, AHCI_PX_TFD),
+                  AHCI_PX_TFD_STS_BSY) ||
+           BITSET(ahci_px_rreg(ahci, cmd->port, AHCI_PX_CI), (1 << cmd->slot))) {
+        usleep(50);
+    }
+}
+
+void ahci_command_issue(AHCIQState *ahci, AHCICommand *cmd)
+{
+    ahci_command_issue_async(ahci, cmd);
+    ahci_command_wait(ahci, cmd);
+}
+
+uint8_t ahci_command_slot(AHCICommand *cmd)
+{
+    return cmd->slot;
+}
diff --git a/tests/libqos/ahci.h b/tests/libqos/ahci.h
index 83a62ac..6ca1a6e 100644
--- a/tests/libqos/ahci.h
+++ b/tests/libqos/ahci.h
@@ -418,6 +418,9 @@ typedef struct PRD {
     uint32_t dbc;  /* Data Byte Count (0-indexed) & Interrupt Flag (bit 2^31) */
 } __attribute__((__packed__)) PRD;
 
+/* Opaque, defined within ahci.c */
+typedef struct AHCICommand AHCICommand;
+
 /*** Macro Utilities ***/
 #define BITANY(data, mask) (((data) & (mask)) != 0)
 #define BITSET(data, mask) (((data) & (mask)) == (mask))
@@ -517,5 +520,20 @@ void ahci_set_command_header(AHCIQState *ahci, uint8_t port,
 void ahci_destroy_command(AHCIQState *ahci, uint8_t port, uint8_t slot);
 void ahci_write_fis(AHCIQState *ahci, RegH2DFIS *fis, uint64_t addr);
 unsigned ahci_pick_cmd(AHCIQState *ahci, uint8_t port);
+unsigned size_to_prdtl(unsigned bytes, unsigned bytes_per_prd);
+
+/* Command Lifecycle */
+AHCICommand *ahci_command_create(uint8_t command_name);
+void ahci_command_commit(AHCIQState *ahci, AHCICommand *cmd, uint8_t port);
+void ahci_command_issue(AHCIQState *ahci, AHCICommand *cmd);
+void ahci_command_issue_async(AHCIQState *ahci, AHCICommand *cmd);
+void ahci_command_wait(AHCIQState *ahci, AHCICommand *cmd);
+void ahci_command_free(AHCICommand *cmd);
+
+/* Command adjustments */
+void ahci_command_set_buffer(AHCICommand *cmd, uint64_t buffer);
+
+/* Command Misc */
+uint8_t ahci_command_slot(AHCICommand *cmd);
 
 #endif